Loomis Sayles Funds I

Loomis, Sayles & Company, L.P., which has been an investment adviser since 1926, is the investment adviser of the Funds.

The Securities and Exchange Commission has not approved or disapproved any Fund’s shares or determined whether this Prospectus is truthful or complete. Any representation to the contrary is a crime.

To learn more about the possible risks of investing in the Funds, please refer to the section “Summary of Principal Risks.” This section details the risks of practices in which the Funds may engage. Please read this section carefully before you invest.

Fund shares are not bank deposits and are not guaranteed, endorsed or insured by the Federal Deposit Insurance Corporation or any other government agency, and are subject to investment risks, including possible loss of the principal invested.

Investment Objective The Fund’s investment objective is high current income. Capital appreciation is the Fund’s secondary objective. The Fund’s investment objectives are fundamental and may not be changed without the approval of shareholders.

Principal Investment Strategies Under normal market conditions, the Fund will invest substantially all of its assets, and may invest up to 100% of its assets, in high income securities. “High Income Securities” are fixed-income securities that Loomis, Sayles & Company, L.P. (“Loomis Sayles”) believes have the potential to generate relatively high levels of current income. High Income Securities may include debt securities that are rated below investment grade quality at the time of investment (i.e., none of the three major ratings agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Rating Group) have rated the securities in one of their respective top four ratings categories) or, if unrated, are determined to be of comparable quality by Loomis Sayles. These high yield debt securities are commonly called “junk bonds.” High Income Securities may also include investment grade fixed-income securities. The Fund may invest approximately 20% of its assets in investment grade fixed-income securities. High Income Securities may be convertible into, or exchangeable for, equity securities or they may carry with them the right to acquire equity securities evidenced by warrants attached to the debt security or acquired as part of a unit with the debt security. The High Income Securities in which the Fund invests may have fixed or variable principal payments and all types of interest rate and dividend and reset terms, including fixed rate, adjustable rate, zero-coupon, contingent, deferred, pay-in-kind and auction rate. The Fund may invest a portion of its assets in senior floating rate loans made to U.S. and foreign borrowers. A significant portion of the securities purchased by the Fund may be issued by smaller-capitalization companies.

Under normal market conditions, the Fund may invest up to 40% of its assets in debt obligations of foreign companies, foreign governments and their subdivisions, agencies, instrumentalities and sponsored entities (“Foreign Securities”), including emerging markets securities. The Fund’s investments in Foreign Securities will be denominated in U.S. dollars and the Fund may invest without limit in obligations of supranational entities (e.g., the World Bank). The Fund may also invest in derivatives, including swaps (including credit default swaps) purchasing or selling options or futures contracts to hedge interest rate risk, and engaging in other derivative transactions.

The Fund’s investments may include corporate debt securities, U.S. Government obligations, U.S. dollar-denominated foreign securities, zero-coupon and pay-in-kind securities, loan assignments and participations, delayed funding loans and revolving credit facilities, commercial paper, mortgage-backed securities, collateralized mortgage obligations, mortgage dollar rolls, collateralized debt and loan obligations and other asset-backed securities, Rule 144A securities, when-issued securities, municipal bonds, repurchase agreements, debt-linked and equity-linked securities, convertible securities, preferred shares and illiquid securities. The Fund may also engage in short sales.

Loomis Sayles’ staff monitors the credit quality of the securities owned by the Fund. Although Loomis Sayles considers public credit ratings when making investment decisions, it performs its own credit and investment analysis and does not rely primarily on the ratings assigned by ratings services.

The Fund may purchase unrated securities (securities that are not rated by a rating agency) if Loomis Sayles determines that the securities are of comparable quality to rated securities that the Fund may purchase. An unrated security may be less liquid than a comparable rated security and involves the risk that Loomis Sayles may not accurately evaluate the security’s comparative credit rating. Analysis of the creditworthiness of issuers of high yield securities may be more complex than for issuers of higher-quality debt obligations. To the extent that the Fund invests in high yield and/or unrated securities, the Fund’s success in achieving its investment objectives may depend more heavily on Loomis Sayles’ creditworthiness analysis than if the Fund invested exclusively in higher-quality and rated securities.

Loomis Sayles believes that high total returns may be obtained through fundamental analysis. In deciding which High Income Securities to buy and sell, Loomis Sayles will consider, among other things, the financial strength of the issuer, yield, coupon rate, current interest rates and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return of those types of investments. As part of its investment approach, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles Loomis Sayles believes have the potential to stabilize or improve. With respect to investments in Foreign Securities, Loomis Sayles will consider the global economic environment, and the economic environment of the relevant country, taking into account factors such as GDP growth, inflation and other economic conditions, monetary policy, fiscal policy, leadership and social stability.

Loomis Sayles makes significant use of non-market related securities, which are securities that may not have a direct correlation with changes in interest rates. Loomis Sayles believes the Fund may generate positive returns by having a portion of the Fund’s assets invested in non-market related securities, rather than

relying primarily on changes in interest rates to produce returns. Loomis Sayles also analyzes different sectors of the economy and differences in the yields of various fixed-income securities in an effort to find fixed-income securities that Loomis Sayles believes may provide attractive returns for the Fund in comparison to their risk.

The Fund is “non-diversified.” As a non-diversified fund, the Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers, as compared with other mutual funds that are diversified.

The Fund may also invest in swaps (including credit default swaps) and other derivatives.

As a temporary defensive measure, the Fund may invest any portion of its assets in cash (U.S. dollars, foreign currencies or multinational currency units) and/or invest up to 100% of its assets in high quality debt securities or money market instruments of U.S. or foreign issuers. The Fund may miss certain investment opportunities if it uses defensive strategies and thus may not achieve its investment objective.

Principal Risks The principal risks of investing in the Fund are described below. There are other circumstances (including non-principal risks that are not described here) which could prevent the Fund from achieving its investment goals. You may lose money by investing in the Fund.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially, or be otherwise unwilling or unable to meet their obligations to the Fund. This risk is generally more pronounced for funds that may invest a significant portion of their assets in non-investment grade securities, such as the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Derivatives Risk is the risk that the value of the Fund’s derivative investments will fall, for example, because of changes in the value of the underlying reference instruments, pricing difficulties or lack of correlation with the underlying investment.

Emerging Markets Risk is the risk that the Fund’s investments may face greater foreign securities risk since emerging markets countries may be more likely to experience political or economic instability than larger, more established foreign countries.

Extension Risk is the risk that an unexpected rise in interest rates will extend the life of a mortgage- or asset-backed security beyond the expected prepayment time, typically reducing the security’s value.

Foreign Securities Risk is the risk that the value of the Fund’s foreign investments will fall as a result of foreign political, social, economic or currency changes or other issues related to foreign investing generally. Although the Fund will invest only in U.S. dollar-denominated securities, the value of these investments may be affected by changes in currency exchange rates. The Fund’s investments in foreign securities may be subject to foreign withholding taxes. In that case, the Fund’s yield on those securities would be decreased.

High Yield Securities Risk is the risk associated with investing in high yield securities and unrated securities of similar quality (commonly known as “junk bonds”), which may be subject to greater levels of interest rate, credit and liquidity risk than other securities. These securities are considered predominantly speculative with respect to the issuer’s continuing ability to make principal and interest payments. In addition, an economic downturn or period of rising interest rates could adversely affect the market for these securities and reduce the Fund’s ability to sell them.

Inflation/Deflation Risk is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases the present value of future payments. Deflation risk is the risk that prices throughout the economy decline over time — the opposite of inflation. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund’s portfolio.

Interest Rate Risk is the risk that the value of the Fund’s investments will fall if interest rates rise. Interest rate risk generally is greater for funds that invest in fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations.

Issuer Risk is the risk that the value of securities may decline due to a number of reasons relating to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Lower-Quality Fixed-Income Securities Risk is the risk that the Fund’s investments in lower-quality fixed-income securities may be subject to greater risks than other fixed-income securities. The ability of the issuer to make principal and interest payments is predominantly speculative for lower-quality fixed-income securities.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Market Risk is the risk that the market value of a security may move up and down, sometimes rapidly and unpredictably, based upon a change in an issuer’s financial condition, as well as overall market and economic conditions.

Mortgage-Related Securities Risk is the risk that the securities may be prepaid and result in the reinvestment of the prepaid amounts in securities with lower yields than the prepaid obligations. The Fund may also incur a loss when there is a prepayment of securities that were purchased at a premium. The market for mortgage-backed securities (and other asset-backed securities) has experienced high volatility and a lack of liquidity. As a result, the value of many of these securities has significantly declined. There can be no assurance that these markets will become more liquid or less volatile, and it is possible that the value of these securities could decline further.

Non-Diversification Risk is the risk that the Fund, when compared with other mutual funds, may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, the Fund may have more risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund’s net asset value.

Small Capitalization Companies Risk is the risk that small-cap companies tend to have more limited markets and resources, and less liquidity, than companies with larger market capitalizations, therefore, the performance of securities issued by small-cap companies can be more volatile than, and perform differently from, larger capitalization securities.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year and since inception periods compared to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each calendar year since its first full year of operations.

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]%, ([ ]quarter of [ ]), and the Fund’s worst quarter was down [ ]%, ([ ] quarter of [ ]).

Performance Table The table below shows how the average annual total returns for Institutional Class shares of the Fund (before and after taxes) for the one year and since inception periods compare to those of the Barclays Capital High Yield Index (formerly known as “Lehman High Yield Index”), an unmanaged, market-weighted index of fixed-rate, non-investment grade debt (the Fund’s primary broad-based index). The returns of the Fund are also compared to the returns of the Lipper High Current Yield Funds Index, an unmanaged, equally weighted index of typically the 30 largest mutual funds that have high current yield as an investment objective. You may not invest directly in an index. The Fund’s returns have also been calculated to reflect returns after taxes on distributions only and also returns after taxes on distributions and sale of Fund shares. The Barclays Capital High Yield Index and the Lipper High Current Yield Funds Index returns have not been adjusted for ongoing, management, distribution and operating expenses applicable to mutual fund shares.

Investment Objective The Fund’s investment objective is to seek a high level of current income consistent with capital preservation.

Principal Investment Strategies The Fund’s investment adviser, Loomis, Sayles & Company, L.P. (“Loomis Sayles”) seeks to achieve the Fund’s objective by investing at least 80% of the Fund’s net assets (plus any borrowings made for investment purposes) in a diversified portfolio of securitized assets, such as mortgage-backed and other asset-backed securities. In accordance with applicable Securities and Exchange Commission (“SEC”) requirements, the Fund will notify shareholders prior to any change to such policy taking effect. Although under normal circumstances the Fund’s investments are expected to consist primarily of mortgage-backed and other asset-backed securities similar to those in the Barclays Capital Securitized Index (formerly known as “Lehman Brothers Securitized Index”), the Fund may invest in any type of asset-backed security. The Fund may only buy securities that are rated investment grade at the time of purchase by at least one of the three major rating agencies (such as Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Rating Group) or, if unrated, are determined by Loomis Sayles to be of comparable quality. It is expected that a majority of the Fund’s securities will be rated AAA or Aaa by at least one of the rating agencies. The Fund may continue to hold securities that are downgraded in quality subsequent to their purchase if Loomis Sayles believes it would be advantageous to do so. The Fund may invest in both fixed and floating rate instruments.

The following is a list of securities in which, among others, the Fund may invest:

Loomis Sayles uses a bottom-up, fundamental research process to select individual securities for the Fund. Loomis Sayles will seek to construct a portfolio with risk characteristics similar but not identical to the securities in the Barclays Capital Securitized Index (the “Index”). Examples of typical risk characteristics that Loomis Sayles might consider include average life, credit quality, effective duration, yield curve exposure and sector exposure, among others. The portfolio

will not necessarily exhibit similarities with the Index for some or all risk characteristics. It is currently anticipated that the Fund’s effective duration will be within +/- 1 year of the effective duration of the Index.

The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts (including on a “to be announced” basis) or by using investment techniques such as buybacks and dollar rolls.

The Fund’s investments may also include the following: U.S. Government securities, corporate debt securities, zero-coupon securities, step coupon securities, commercial paper, structured notes, other mortgage-related securities (including adjustable rate mortgage securities, stripped mortgage-backed securities and mortgage dollar rolls), when-issued securities, and repurchase agreements. The Fund may also invest in options, futures, swaps (including credit default swaps) and other derivatives transactions.

The Fund may engage in active and frequent trading of securities. Frequent trading may produce high transaction costs and a high level of taxable capital gains, which may lower the Fund’s return.

As a temporary defensive measure, the Fund may invest any portion of its assets in cash (U.S. Dollars, foreign currencies or multinational currency units), and/or invest up to 100% of its assets in high quality debt securities or money market instruments of U.S. or foreign issuers. The Fund may miss certain investment opportunities if it uses defensive strategies and thus may not achieve its investment objective.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each calendar year since its first full year of operations.

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]%, ([ ] quarter of [ ]), and the Fund’s worst quarter was down [ ]%, ([ ] quarter of [ ]).

Performance Table The table below shows how the average annual total returns for Institutional Class shares of the Fund (before and after taxes) for the one-year and since inception periods compare to those of the Barclays Capital Securitized Index, an unmanaged index of asset-backed securities, collateralized mortgage-backed securities (Employee Retirement Income Security Act (“ERISA”) eligible) and fixed rate mortgage-backed securities (the Fund’s primary broad-based index). The returns of the Fund are also compared to the returns of the Lipper US Mortgage Funds Index, an unmanaged, equally weighted index of typically the 30 largest US mortgage funds as tracked by Lipper Inc. You may not invest directly in an index. The Fund’s returns have also been calculated to reflect return after taxes on distributions only and also return after taxes on distributions and sale of Fund shares. The Barclays Capital Securitized Index and the Lipper US Mortgage Funds Index returns have not been adjusted for ongoing, management, distribution and operating expenses applicable to mutual fund shares.

The following table describes the fees and expenses that you may pay if you buy and hold shares of a Fund.

None of the Funds impose a sales charge, a redemption fee, or an exchange fee.¹

ANNUAL FUND OPERATING EXPENSES (expenses that are deducted from each fund’s assets, as a percentage of daily net assets)

The example, which is based upon the expenses shown in the “Total Annual Fund Operating Expenses” column, is intended to help you compare the cost of investing in the Funds with the cost of investing in other mutual funds.

The example assumes that you invest $10,000 in the Funds for the time periods indicated; your investment has a 5% return each year; the Funds’ operating expenses remain the same; and all dividends and distributions are reinvested.

Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

This section provides more information on the principal risks that may affect a Fund’s portfolio. In seeking to achieve their investment goals, the Funds may also invest in various types of securities and engage in various investment practices which are not a principal focus of the Funds and therefore are not described in this Prospectus. These securities and investment practices and their associated risks are discussed in the Funds’ Statement of Additional Information (“SAI”), which is available without charge upon request (see back cover).

Each Fund may borrow money for temporary or emergency purposes in accordance with its investment restrictions.

This is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to an over-the-counter transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. Each Fund may be subject to credit risk to the extent that it invests in fixed-income securities or is a party to over-the-counter transactions.

A Fund that invests in lower-rated fixed-income securities (“junk bonds”) are subject to greater credit risk and market risk than a fund that invests in higher-quality fixed-income securities. Lower-rated fixed-income securities are considered predominantly speculative with respect to the ability of the issuer to make timely principal and interest payments.

A Fund that invests in fixed-income securities issued in connection with corporate restructurings by highly-leveraged issuers or in fixed-income securities that are not current in the payment of interest or principal (i.e., in default) will be subject to greater credit risk.

A Fund that invests in non-U.S. securities is subject to increased credit risk, for example, because of the difficulties of requiring non-U.S. entities to honor their contractual commitments and because a number of non-U.S. governments and other issuers are already in default.

This is the risk that fluctuations in exchange rates between the U.S. dollar and non-U.S. currencies may cause the value of a Fund’s investments to decline. A Fund that may invest in securities denominated in, or receive revenues in, non-U.S. currency are subject to currency risk.

Each Fund may use derivatives, which are financial contracts whose value depends upon or is derived from the value of an underlying asset, reference rate, or index. Examples of derivatives include options, futures and swap transactions (including credit default swaps), foreign transactions and foreign currency transactions. The Funds may (but are not required to) use derivatives as part of a strategy designed to reduce exposure to other risks, such as risks associated with changes in interest rates or currency risk (“hedging”). The Funds may also use derivatives for leverage, which increases opportunities for gain but also involves greater risk of loss due to leveraging risk, and to earn income, enhance yield, or broaden the Fund’s diversification by gaining exposure to issuers, indices, sectors, currencies and/or geographic regions. This use of derivatives for these purposes entails greater risk than using derivatives solely for hedging purposes.

Funds that use derivatives also face additional risks, such as liquidity risk, market risk, management risk, the credit risk relating to the other party to a derivative contract, the risk of difficulties in pricing and valuation, the risk of ambiguous documentation and the risk that changes in the value of a derivative may not correlate perfectly with relevant assets, rates or indices. This could, for example, cause a derivative transaction to imperfectly hedge the risk which it was intended to hedge. A Fund’s use of derivative instruments may involve risks greater than the risks associated with investing directly in securities and other traditional investments, may cause the Fund to lose more than the principal amount invested and may subject a Fund to the potential for unlimited loss. A Fund may be required to sell other securities at inopportune times to meet collateral requirements on its derivatives transactions. In addition, a Fund’s use of derivatives may increase or accelerate the amount of taxes payable by shareholders. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that a Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial or that, if used, such strategies will be successful.

Recently, several broker-dealers and other financial institutions have experienced extreme financial difficulty, sometimes resulting in bankruptcy of the institution. Although the Fund’s adviser monitors the creditworthiness of the Fund’s derivative counterparties, there can be no assurance that the Fund’s counterparties will not experience similar difficulties, possibly resulting in losses to the Fund. Losses resulting from the use of derivatives will reduce the Fund’s net asset value, and possibly income, and the losses may be significantly greater than if derivatives had not been used.

Economic and Political Risks. Emerging market countries often experience instability in their political and economic structures. Government actions could have a significant impact on the economic conditions in such countries, which in turn would affect the value and liquidity of the assets of a Fund invested in emerging markets securities. Specific risks that could decrease a Fund’s return include seizure of a company’s assets, restrictions imposed on payments as a result of blockages on foreign currency exchanges and unanticipated social or political occurrences.

The ability of the government of an emerging market country to make timely payments on its debt obligations will depend on many factors, including the extent of its reserves, fluctuations in interest rates, and access to international credit and investments. A country that has non-diversified exports or relies on certain key imports will be subject to greater fluctuations in the pricing of those commodities. Failure to generate sufficient earnings from foreign trade will make it difficult for an emerging market country to service its foreign debt.

Companies trading in developing securities markets are generally smaller and have shorter operating histories than companies trading in developed markets. Foreign investors may be required to register the proceeds of sales. Settlement of securities transactions in emerging markets may be subject to risk of loss and may be delayed more often than transactions settled in the U.S. Disruptions resulting from social and political factors may cause the securities markets to close. If extended closings were to occur, the liquidity and value of the Fund’s assets invested in corporate debt obligations of emerging market companies would decline.

Investment Controls; Repatriation. Foreign investment in emerging market country debt securities is restricted or controlled to varying degrees. These restrictions may at times limit or preclude foreign investment in certain emerging market country debt securities. Certain emerging market countries require government approval before investments by foreign persons, limit the amount of investments by foreign persons in a particular issuer, limit investments by foreign persons only to a specific class of securities of an issuer that may have less advantageous rights than the classes available for purchase by domiciliaries of the countries and/or impose additional taxes on foreign investors. Certain emerging market countries may also restrict investment opportunities in issuers in industries deemed important to national interests.

to grant, any required governmental approval for repatriation of capital, as well as by the application to a Fund of any restrictions on investments. Investing in local markets in emerging market countries may require a Fund to adopt special procedures, seek local governmental approvals or take other actions, each of which may involve additional costs to a Fund.

This is the risk that the value of fixed income securities in the Fund’s portfolio may decline for a number of reasons which relate directly to the issuer. This may include, among other things, management performance, the effects of financial leverage and reduced demand for a company’s goods and services. Fixed income securities are also subject to credit risk, interest rate risk and liquidity risk.

This is the risk associated with investments in issuers located or that do business in foreign countries. The High Income Opportunities Fund is subject to this risk because it may invest up to 40% of its assets in securities of non-U.S. issuers. The Fund’s investments in foreign securities may be less liquid and may experience more rapid and extreme changes in value than investments in securities of U.S. companies.

The securities markets of many foreign countries are relatively small, with a limited number of issuers and a small number of securities. In addition, foreign companies often are not subject to the same degree of regulation as U.S. companies. Reporting, accounting, and auditing standards of foreign countries differ, in some cases significantly, from U.S. standards. Among other things, nationalization, expropriation or confiscatory taxation, currency blockage, political changes, or diplomatic developments can cause the value of the Fund’s investments in a foreign country to decline. In the event of nationalization, expropriation, or other confiscation, a fund that invests in foreign securities could lose its entire investment.

As described further under “Emerging Markets Risk” above, funds that invest in emerging markets may face greater foreign risk since emerging markets countries may be more likely to experience political and economic instability, and generally are subject to a greater degree to the risks generally applicable to foreign securities.

Although the Funds will invest only in U.S. dollar-denominated securities, the value of these securities may be adversely affected by changes in currency exchange rates.

Compared with other mutual funds, each Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, each Fund may be subject to greater risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund’s net asset value.

High yield securities are generally below investment grade quality. To be considered below investment grade quality, none of the three major rating agencies (Moody’s, Fitch & S&P) must have rated the security in one of their respective top four rating categories at the time a Fund acquires the security or, if the security is unrated, Loomis Sayles must have determined it to be of comparable quality. These lower-rated securities, commonly known as “junk bonds,” may be considered speculative with respect to the issuer’s continuing ability to make principal and interest payments. Analysis of the creditworthiness of issuers of lower-rated securities may be more complex than for issuers of higher quality debt securities, and the Fund’s ability to achieve its investment objectives may, to the extent the Fund invests in lower-rated securities, be more dependent upon Loomis Sayles’ credit analysis than would be the case if the Fund were investing in higher quality securities. The issuers of these securities may be in default or have a currently identifiable vulnerability to default on their payments of principal and interest, or may otherwise be subject to present elements of danger with respect to payments of principal or interest. However, the Funds will not invest in securities that are in default as to payment of principal and interest at the time of purchase.

Lower-rated securities may be more susceptible to real or perceived adverse economic and competitive industry conditions than higher grade securities.

The prices of lower-rated securities have been found to generally be less sensitive to interest-rate changes than more highly rated investments, but more sensitive to adverse economic downturns or individual corporate developments. Yields on lower-rated securities will fluctuate. If the issuer of lower-rated securities defaults, the Funds may incur additional expenses to seek recovery.

The secondary markets in which lower-rated securities are traded may be less liquid than the market for higher grade securities. A lack of liquidity in the secondary trading markets could adversely affect the price at which a Fund could sell a particular lower-rated security when necessary to meet liquidity needs or in response to a specific economic event, such as a deterioration in the creditworthiness of the issuer, and could adversely affect and cause large fluctuations in the net asset value of the Fund’s shares. Adverse publicity and investor perceptions may decrease the values and liquidity of high yield securities generally.

It is reasonable to expect that any adverse economic condition could disrupt the market for lower-rated securities, have an adverse impact on the value of such securities, and adversely affect the ability of the issuers of such securities to repay principal and pay interest thereon. New laws and proposed new laws may adversely impact the market for lower-rated securities.

Inflation risk is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases the present value of future payments. Deflation risk is the risk that prices throughout the economy decline over time (the opposite of inflation). Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of a Fund’s portfolio.

Even funds that generally invest a significant portion of their assets in high quality fixed-income securities are subject to interest rate risk. Interest rate risk is greater for funds, such as the Funds, that generally invest a significant portion of their respective assets in lower rated fixed-income securities or comparable unrated securities (commonly known as “junk bonds”).

The Funds will be subject to increased interest rate risk to the extent that they invest in fixed-income securities with longer maturities or durations, as compared to if they invested in fixed-income securities with shorter maturities or durations.

Interest rate risk is compounded for funds that invest a significant portion of their assets in mortgage-related or other asset-backed securities because the value of mortgage-related securities and asset-backed securities generally is more sensitive to changes in interest rates than other types of fixed-income securities. When interest rates rise, the maturities of mortgage-related and asset-backed securities tend to lengthen, and the value of the securities decreases more significantly. In addition, these types of securities are subject to prepayment when interest rates fall, which generally results in lower returns because funds that hold these types of securities must reinvest assets, previously invested in these types of securities in fixed-income securities with lower interest rates.

The Funds also face increased interest rate risk when they invest in interest-only securities or fixed-income securities paying no current interest, such as zero-coupon securities, principal-only securities, and fixed-income securities paying non-cash interest in the form of other fixed-income securities.

The value of a Fund’s investments may decline for a number of reasons which directly relate to an issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. Because asset-backed securities are typically pools of other securities or assets, this risk also relates to the issuer of securities backing the asset-backed securities in which a Fund invests.

When a Fund borrows money or otherwise leverages its portfolio, the value of an investment in the Fund will be more volatile, and all other risks are generally compounded. Funds face this risk if they create leverage by using investments such as reverse repurchase agreements, inverse floating rate instruments or derivatives, or by borrowing money.

Liquidity risk exists when particular investments are difficult to purchase or sell, possibly preventing a Fund from selling these illiquid securities at the price or at the time desired. Liquidity issues can also make it difficult to value a Fund’s investments, which also could have a negative impact on net asset value. Derivatives and securities that involve substantial interest rate risk or credit risk tend to involve greater liquidity risk. In addition, liquidity risk tends to increase to the extent the Fund invests in securities whose sale may be restricted by law or by contract, such as Rule 144A securities.

Management risk is the risk that Loomis Sayles’ investment techniques could fail to achieve a Fund’s objective and could cause your investment in a Fund to lose value. The Funds are subject to management risk because they are actively managed by Loomis Sayles. Loomis Sayles will apply its investment techniques and risk analyses in making investment decisions for each Fund, but there can be no guarantee that Loomis Sayles’ decisions will produce the desired results. For example, securities that Loomis Sayles expects may appreciate in value may in fact decline. Similarly, in some cases derivative and other investment techniques may be unavailable or Loomis Sayles may determine not to use them, even under market conditions where their use could have benefited a Fund.

Market risk is the risk that the value of a Fund’s investments will change as financial markets fluctuate and that prices overall may decline. The value of a company’s securities may fall as a result of factors that directly relate to that company, such as decisions made by its management or lower demand for the company’s products or services. A security’s value also may fall because of factors affecting not just the issuer of a security, but other companies in its industry or in a number of different industries, such as increases in production costs. The value of a Fund’s securities also may be affected by changes in financial market or other economic conditions, such as changes in interest rates or currency exchange rates. In addition, a company’s stock generally pays dividends only after the company makes required payments to holders of its bonds or other debt. For this reason, the value of the stock will usually react more strongly than bonds and other fixed-income securities to actual or perceived changes in the company’s financial condition or prospects. Market risk tends to be greater when a Fund invests in fixed-income securities with longer maturities.

Securities issued in initial public offerings (“IPOs”) tend to involve greater market risk than other equity securities due, in part, to public perception and the lack of publicly available information and trading history. This may impact a Fund’s performance and result in higher portfolio turnover, which may increase the tax liability to shareholders and the brokerage expenses incurred by the Fund.

Mortgage-related securities, such as Government National Mortgage Association certificates or securities issued by the Federal National Mortgage Association, differ from traditional fixed-income securities. Among the major differences are that interest and principal payments are made more frequently, usually monthly, and that principal may be prepaid at any time because the underlying mortgage loans generally may be prepaid at any time. As a result, if a Fund purchases these assets at a premium, a faster-than-expected prepayment rate will reduce yield to maturity, and a slower-than-expected prepayment rate will increase yield to maturity. If a Fund purchases mortgage-related securities at a discount, faster-than-expected prepayments will increase, and slower-than-expected prepayments will reduce, yield to maturity. Prepayments, and resulting amounts available for reinvestment by the Fund, are likely to be greater during a period of declining interest rates and, as a result, are likely to be reinvested at lower interest rates. Accelerated prepayments on securities purchased at a premium may result in a loss of principal if the premium has not been fully amortized at the time of prepayment. These securities will decrease in value as a result of increases in interest rates generally, and they are likely to appreciate less than other fixed-income securities when interest rates decline because of the risk of prepayments.

The value of some mortgage-backed securities in which a Fund invests may be particularly sensitive to changes in prevailing interest rates, and the ability of a Fund to successfully utilize these instruments may depend in part upon the ability of the Fund’s adviser to forecast interest rates and other economic factors correctly. The risk of non-payment is greater for mortgage-related securities that are backed by mortgage pools that contain “subprime” or “Alt-A” loans (loans made to borrowers with weakened credit histories or with a lower capacity to make timely payments on their loans), but a level of risk exists for all loans. Market factors adversely affecting mortgage loan repayments may include a general economic turndown, high unemployment, a general slowdown in the real estate market, a drop in the market prices of real estate, or an increase in interest rates resulting in higher mortgage payments by holders of adjustable rate mortgages.

A mortgage dollar roll involves the sale of a security by a Fund and its agreement to repurchase the instrument at a specified time and price, and may be considered a form of borrowing for some purposes. A Fund will segregate assets determined to be liquid in an amount sufficient to meet its obligations under the transactions. A dollar roll involves potential risks of loss that are different from those related to the securities underlying the transactions. A Fund may be required to purchase securities at a higher price than may otherwise be available on the open market. Since the counterparty in the transaction is required to deliver a similar, but not identical, security to a Fund, the security that a Fund is required to buy under the dollar roll may be worth less than an identical security. There is no assurance that a Fund’s use of the cash that it receives from a dollar roll will provide a return that exceeds borrowing costs.

Under a repurchase agreement, a Fund purchases a security and obtains a simultaneous commitment from the seller (a bank or, to the extent permitted by the 1940 Act, a recognized securities dealer) to repurchase the security at an agreed upon price and date (usually seven days or less from the date of original purchase). The resale price is in excess of the purchase price and reflects an agreed upon market rate of interest unrelated to the coupon rate on the purchased security. Such transactions afford the Fund the opportunity to earn a return on its cash at what is expected to be minimal market risk. There is a risk that the seller may fail to repurchase the underlying security. In such event, the Fund would attempt to exercise rights with respect to the underlying security, including possible disposition in the market. However, the Fund may be subject to various delays and risks of loss, including possible declines in the value of the underlying security, possible reduced levels of income, inability to enforce rights and expenses involved in attempted enforcement. Repurchase agreements maturing in more than seven days may be considered illiquid securities.

The general risks associated with corporate income-producing securities are particularly pronounced for securities issued by companies with smaller market capitalizations. These companies may have limited product lines, markets or financial resources or they may depend on a few key employees. As a result, they may be subject to greater levels of credit, market and issuer risk. Securities of smaller companies may trade less frequently and in lesser volume than more widely held securities and their values may fluctuate more sharply than other securities. Further, securities of smaller companies may perform differently in different cycles than larger company securities. Companies with medium-sized market capitalizations may have risks similar to those of smaller companies.

The Funds may lend a portion of their portfolio securities to brokers, dealers, and other financial institutions provided a number of conditions are satisfied, including that the loan is fully collateralized. Please see “Investment Strategies” in the SAI for details. When a Fund lends portfolio securities, its investment performance will continue to reflect changes in the value of the securities loaned, and the Fund will also receive a fee or interest on the collateral. Securities lending involves the risk of loss of rights in the collateral or delay in recovery of the collateral if the borrower fails to return the security loaned or becomes insolvent.

In addition, any investment of cash collateral is generally at the sole risk of the Funds. Any income or gains and losses from investing and reinvesting any cash collateral delivered by a borrower pursuant to a loan are generally at the Fund’s risk, and to the extent any such losses reduce the amount of cash below the amount required to be returned to the borrower upon the termination of any loan, the Fund may be required by the securities lending agent to pay or cause to be paid to such borrower an amount equal to such shortfall in cash, possibly requiring it to liquidate other portfolio securities to satisfy its obligations. A Fund may pay lending fees to the party arranging the loan.

in the principal amount payable with respect to, or the interest rate of, a structured note may be a multiple of the percentage change (positive or negative) in the value of the underlying reference instrument or instruments. Structured notes can be used to increase a Fund’s exposure to changes in the value of assets or to hedge the risks of other investments that a Fund holds.

Investment in structured notes involves certain risks, including the risk that the issuer may be unable or unwilling to satisfy its obligations to pay principal or interest, which are separate from the risk that the note’s reference instruments may move in a manner that is disadvantageous to the holder of the note. Structured notes, which are often illiquid, are also subject to additional risk such as market risk, liquidity risk, and interest rate risk. The terms of certain structured notes may provide that a decline in the reference instrument may result in the interest rate or principal amount being reduced to zero. Structured notes may be more volatile than the underlying reference instruments or traditional debt instruments.

Pursuant to SEC exemptive relief, each Fund may be permitted to invest its daily cash balances in shares of money market and short-term bond funds advised by Natixis Asset Management Advisors, L.P. (“Natixis Advisors”) (an affiliate of Loomis Sayles) or its affiliates (the “Central Funds”). The Central Funds currently include two money market funds: Natixis Cash Management Trust — Money Market Series (the “Money Market Fund”) and Daily Income Fund. The Money Market Fund is advised by Natixis Advisors and subadvised by Reich & Tang and the Daily Income Fund is advised by Reich & Tang. Because Loomis Sayles, Natixis Advisors and Reich & Tang are each subsidiaries of Natixis Global Asset Management, L.P. (“Natixis US”), the Funds and the Central Funds may be considered to be related companies comprising a “group of investment companies” under the 1940 Act.

Each of these advisers and subadvisers (except for BlackRock and Dreman) are subsidiaries of Natixis US and are thus “affiliated persons” under the 1940 Act by reason of being under common control by Natixis US. In addition, because the Funds, and other funds, are advised by firms that are affiliated with one another, they may be considered to be related companies comprising a “group of investment companies” under the 1940 Act. The Central Funds will participate in the credit facility only as lenders. Participation in such an interfund lending program would be voluntary for both borrowing and lending funds, and a Fund would participate in an interfund lending program only if the Board of Trustees determined that doing so would benefit a Fund. Should a Fund participate in such an interfund lending program, the Board of Trustees would establish procedures for the operation of the program by the advisers or an affiliate. The Funds may engage in the transactions described above without further notice to shareholders. The Funds may also make investments in related investment companies to the extent permitted by SEC regulations.

Loomis Sayles, located at One Financial Center, Boston, Massachusetts 02111, serves as the investment adviser to the Funds. Loomis Sayles is a subsidiary of Natixis Asset Management US Group which is part of Natixis Asset Management Group, an international asset management group based in Paris, France. Founded in 1926, Loomis Sayles is one of the oldest investment firms in the U.S. with over $ billion in assets under management as of December 31, 2008. Loomis Sayles is well known for its professional research staff, which is one of the largest in the industry. Loomis Sayles is responsible for making investment decisions for each Fund and for providing general business management and administration to each Fund.

As previously described in the “Expenses of the Funds” section, an investor will either pay a “wrap” fee to the program sponsor and such sponsor will pay a fee to Natixis Advisors, or the investor, such as an institutional client of Loomis Sayles or Natixis Advisors, will pay a fee to Loomis Sayles or Natixis Advisors under a separate client agreement for advisory services. The Funds do not pay Loomis Sayles a monthly investment advisory fee, also known as management fees, for investment advisory services and, except as described below, Loomis Sayles pays the other ordinary expenses of the Funds.

The Funds are each a series of Loomis Sayles Funds I (the “Trust”). The Trust and not Loomis Sayles or its affiliates, will pay the following expenses: taxes payable by the Trust to federal, state or other governmental agencies; extraordinary expenses as may arise, including expenses incurred in connection with litigation, proceedings, other claims and the legal obligations of the Trust or the Funds to indemnify its trustees, officers, employees, shareholders, distributors, and agents with respect thereto; brokerage fees and commissions (including dealer markups) and transfer taxes chargeable to the Trust in connection with the purchase and sale of portfolio securities for the Funds; costs, including any interest expenses, of borrowing money; costs of hedging transactions; costs of lending portfolio securities; and any expenses indirectly incurred through investments in other pooled investment vehicles.

A discussion of the factors considered by the Funds’ Board of Trustees in approving the Funds’ investment advisory contracts is available in the Funds’ annual reports for the fiscal year ended September 30, 2008.

The following persons have had primary responsibility for the day-to-day management of each indicated Fund’s portfolio since the date stated below. Except where noted, each portfolio manager has been employed by Loomis Sayles for at least five years.

Matthew J. Eagan has served as portfolio manager of the Loomis Sayles High Income Opportunities Fund since its inception. Mr. Eagan serves as Vice President and Portfolio Manager of Loomis Sayles. He has over 20 years of investment experience. Mr. Eagan joined Loomis Sayles in 1997. Mr. Eagan received a B.A. from Northeastern University and an M.B.A. from Boston University and holds the designation of Chartered Financial Analyst.

Daniel J. Fuss has served as portfolio manager of the Loomis Sayles High Income Opportunities Fund since its inception. Mr. Fuss has been at Loomis Sayles since 1976 and is currently a Vice Chairman, Director and Managing Partner. He has over 51 years of investment experience. He graduated from Marquette University (B.S. and M.B.A.) and holds the designation of Chartered Financial Analyst.

Kathleen C. Gaffney has served as portfolio manager of the Loomis Sayles High Income Opportunities Fund since its inception. Ms. Gaffney joined Loomis Sayles in 1984. She received a B.A. from the University of Massachusetts at Amherst and has over 25 years of investment experience. She also holds the designation of Chartered Financial Analyst.

Fan Hu has served as portfolio manager of the Loomis Sayles Securitized Asset Fund since April 2006. Ms. Hu, Vice President of Loomis Sayles, began her investment career in 1997 and joined Loomis Sayles in 2006. Prior to joining Loomis Sayles, Ms. Hu was Vice President and mortgage-backed securities strategist at Columbia Management Group (or its predecessor) from 1998 to 2006. She received a B.A. from Nankai University in Tianjin, China, an M.S. from Montana State University and a Ph.D. from North Carolina State University. Ms. Hu is a Chartered Financial Analyst and has over 12 years of investment experience.

Clifton V. Rowe has served as portfolio manager of the Loomis Sayles Securitized Asset Fund since its inception. Mr. Rowe joined Loomis Sayles in 1992 and has over 18 years of investment experience. Prior to serving as a portfolio manager, Mr. Rowe was a trader with Loomis Sayles. Mr. Rowe received a B.B.A. from James Madison University and an M.B.A. from the University of Chicago. He holds the designation of Chartered Financial Analyst.

Elaine M. Stokes has served as portfolio manager of the Loomis Sayles High Income Opportunities Fund since its inception. Ms. Stokes serves as a Vice President and Portfolio Manager of Loomis Sayles. She has over 22 years of investment experience. Ms. Stokes joined Loomis Sayles in 1988. She received a B.S. from St. Michael’s College.

Please see the SAI or information on Portfolio Manager compensation, other accounts under management by the Portfolio Managers and the Portfolio Managers’ ownership of securities in the Funds.

Net asset value (“NAV”) is the price of one share of a Fund without a sales charge and is calculated each business day using this formula:

The net asset value of Fund shares is determined pursuant to policies and procedures approved by the Fund’s Board of Trustees as summarized below:

Generally, during times of substantial economic or market change, it may be difficult to place your order by phone. During these times, you may deliver your order in person to the Fund or send your order by mail as described in the sections “How to Purchase Shares” and “How to Redeem Shares.”

Equity securities. Last sale price on the exchange or market where primarily traded or if there are no reported sales during the day, the closing bid price.

Debt securities (other than short-term obligations). Based upon pricing service valuations, which determine valuations for normal, institutional-size trading units of such securities using market information, transactions for comparable securities and various relationships between securities which are generally recognized by institutional traders.

Short-term obligations (purchased with an original or remaining maturity of 60 days or less). Amortized cost (which approximates market value).

Securities traded on foreign exchanges. Market price on the non-U.S. exchange, unless the Fund believes that an occurrence after the close of that exchange will materially affect the security’s value. In that case, the security may be fair valued at the time the Fund determines its net asset value by or pursuant to procedures approved by the Board of Trustees. When fair valuing securities, the Funds may, among other things, use modeling tools or other processes that may take into account factors such as securities market activity and/or significant events that occur after the close of the local market and before the time a Fund’s net asset value is calculated.

Options. The Funds generally value exchange-traded options at the average of the closing bid and asked quotations.

Futures. Unrealized gain or loss on the contract using current settlement price. When a settlement price is not used, futures contracts will be valued at their fair value as determined by or pursuant to procedures approved by the Board of Trustees.

Credit default swaps. Market value based on prices supplied by a pricing service, if available, or quotations obtained from broker dealers.

Foreign Currency Forward Contracts. Interpolated prices determined from information provided by an independent pricing service.

All other securities. Fair market value as determined by the adviser of the Fund pursuant to procedures approved by the Board of Trustees.

As described above, if market prices are not readily available for a security, securities may not be priced on the basis of quotations from the primary market in which they are traded but rather may be priced by another method that the Board of Trustees believes is more likely to result in a price that reflects fair value (which is the amount that a Fund might reasonably expect to receive from a current sale of the security in the ordinary course of business). A Fund may also value securities at fair value or estimate their value pursuant to procedures approved by the Board of Trustees in other circumstances such as when extraordinary events occur after the close of the relevant market but prior to the close of the NYSE. This may include situations relating to a single issuer (such as a declaration of bankruptcy or a delisting of the issuer’s security from the primary market on which it has traded) as well as events affecting the securities markets in general (such as market disruptions or closings and significant fluctuations in U.S. and/or foreign markets). Fair value pricing may require subjective determinations about the value of a security, and fair values used to determine a Fund’s net asset value may differ from quoted or published prices, or from prices that are used by others, for the same securities. In addition, the use of fair value pricing may not always result in adjustments to the prices of securities held by a Fund.

An investor may purchase Fund shares at net asset value without a sales charge or other fee.

Shares of the Funds are offered exclusively to investors in “wrap fee” programs approved by Natixis Advisors and/or Loomis Sayles and to institutional advisory clients of Loomis Sayles or Natixis Advisors that, in each case, meet the Funds’ policies as established by Loomis Sayles.

A purchase order received by Boston Financial Data Services, Inc., the Funds’ transfer agent (the “Transfer Agent”), prior to the close of regular trading on the NYSE (normally 4:00 p.m. Eastern time), on a day the Funds are open for business, will be effected at that day’s net asset value. An order received after the close of regular trading on the NYSE will be effected at the net asset value determined on the next business day. The Funds are “open for business” on each day the NYSE is open for trading. Purchase orders will be accepted only on days on which the Funds are open for business.

Additional shares can be purchased if authorized by Natixis Advisors or Loomis Sayles and payment must be wired in federal funds to the Transfer Agent except when shares are purchased in exchange for securities acceptable to the Fund.

Purchases of a Fund’s shares will normally be made only in full shares, but may be made in fractional shares under certain circumstances. Certificates for shares will not be issued. The payment for shares to be purchased shall be wired to the Transfer Agent.

Subject to the approval of each Fund, an investor may purchase Institutional Class shares of the Fund with liquid securities and other assets that are eligible for purchase by the Fund (consistent with the Fund’s investment policies and restrictions) and that have a value that is readily ascertainable in accordance with the Fund’s valuation policies. These transactions will be effected only if Loomis Sayles deems the security to be an appropriate investment for a Fund. Assets purchased by a Fund in such a transaction will be valued in accordance with procedures adopted by the Fund. Each Fund reserves the right to amend or terminate this practice at any time.

Please see the section “Restrictions on Buying and Selling Shares” below for more information.

Shares normally can be redeemed only through the shareholder’s wrap program sponsor for shareholders owning shares through wrap accounts or by contacting Loomis Sayles, Natixis Advisors or the Transfer Agent for non-wrap program shareholders.

Redemption requests for Fund shares are effected at the net asset value per share next determined after receipt of a redemption request by the Transfer Agent. A redemption request received by the Transfer Agent prior to the close of regular trading on the NYSE, on a day the Funds are open for business, is effected at that day’s net asset value. A redemption request received after that time is effected at the next business day’s net asset value per share. Redemption proceeds normally will be wired within one business day after the redemption request, but may take up to seven business days. Redemption proceeds will be sent by wire only. The Funds may suspend the right of redemption or postpone the payment date at times when the NYSE is closed, or during certain other periods as permitted under the federal securities laws.

The Funds and the Distributor reserve the right to redeem shares of any shareholder investing through a wrap program at the then-current value of such shares (which will be paid promptly to the shareholder) if the wrap sponsor is no longer approved by Loomis Sayles or Natixis Advisors. The sponsor will receive advance notice of any such mandatory redemption. Similarly, the Funds and the Distributor may redeem shares of any shareholder who no longer participates in an approved wrap program (for example, by withdrawing from the program). The Funds and the Distributor each reserve the right to redeem any shareholder for which Loomis Sayles or Natixis Advisors ceases to act as investment adviser. In addition, the Funds and the Distributor each reserve the right to redeem any shareholder if the shareholder’s continued investment in the Funds becomes inconsistent with each Fund’s policies, as established by Loomis Sayles.

It is highly unlikely that shares would ever be redeemed in-kind. However, in consideration of the best interests of the remaining investors, each Fund reserves the right to pay any redemption proceeds exceeding this amount in whole or in part by a distribution in-kind of securities held by the Funds in lieu of cash. When shares are redeemed in-kind, the redeeming registered investment adviser should expect to incur transaction costs upon the disposition of the securities received in the distribution. Each Fund agrees to redeem shares solely in cash up to the lesser of $250,000 or 1% of each Fund’s net assets during any 90-day period for any one registered investment adviser.

Each Fund reserves the right to create investment minimums in its sole discretion.

The Funds will accept accounts only from U.S. citizens with a U.S. address or resident aliens with a U.S. address and a U.S. taxpayer identification number.

The Funds are required by federal regulations to obtain certain personal information from an investor and to use that information to verify an investor’s identity. A Fund may not be able to open an investor’s account if the requested information is not provided to the Fund or its delegate. The Funds reserve the right to refuse to open an account, close an account and redeem your shares at the then current price or take other such steps that the Funds deem necessary to comply with federal regulations if an investor’s identity is not verified.

Frequent purchases and redemptions of Fund shares by shareholders may present certain risks for other shareholders in a Fund. This includes the risk of diluting the value of Fund shares held by long-term shareholders, interfering with the efficient management of a Fund’s portfolio, and increasing brokerage and administrative costs. A Fund investing in securities that require special valuation processes (such as foreign securities, high yield securities, or small cap securities) may also have increased exposure to these risks. Each Fund discourages excessive, short-term trading that may be detrimental to the Fund and its shareholders. The Funds’ Board of Trustees has adopted the following policies to address and discourage such trading.

The Funds reserve the right to suspend or change the terms of purchasing or exchanging shares. Each Fund and the Distributor reserve the right to reject any purchase or exchange order for any reason, including if the transaction is deemed not to be in the best interests of the Fund’s other shareholders or possibly disruptive to the management of the Fund. A shareholder whose exchange order has been rejected may still redeem their shares by submitting a redemption request as described above under “How to Redeem Shares.”

Limits on Frequent Trading. Without limiting the right of each Fund and the Distributor to reject any purchase or exchange order, each Fund and the Distributor may (but are not obligated to) restrict purchases and exchanges for the accounts of “market timers.” An account may be deemed to be one of a market timer if it makes two “round trips” in any Fund over a 90-day interval, as determined by the Fund. A “round trip” is a purchase (including a purchase by exchange) into the Fund followed by a redemption (including a redemption by exchange) of any amount out of the same Fund. The above limits are applicable whether you hold shares directly with each Fund or indirectly through a financial intermediary, such as a broker, bank, investment adviser, recordkeeper for retirement plan participants, or other third party. The preceding are not exclusive lists of activities that the Funds and the Distributor may consider to be “market timing.”

Notwithstanding the above, certain financial intermediaries, such as retirement plan administrators, may monitor and restrict the frequency of purchase and redemption transactions in a manner different from that described above. The policies of these intermediaries may be more or less restrictive than the generally applicable policies described above. A Fund may choose to rely on a financial intermediary’s restrictions on frequent trading in place of the Fund’s own restrictions if the Fund determines, in its discretion, that the financial intermediary’s restrictions provide reasonable protection for the Fund from excessive short-term trading activity. Please contact your financial representative for additional information regarding their policies for limiting the frequent trading of Fund shares.

This policy also does not apply with respect to shares purchased by a fund-of-funds or similar asset allocation program that rebalances its investments no more frequently than quarterly. To be eligible for this exemption, the fund-of-funds or asset allocation program must identify itself to and receive prior written approval from the applicable Fund or the Distributor. A Fund and the Distributor may request additional information to enable them to determine that the fund-of-funds or asset allocation program is not designed to and/or is not serving as a vehicle for disruptive short-term trading, which may include requests for (i) written assurances from the sponsor or investment manager of the fund-of-funds or asset allocation program that it enforces the Fund’s frequent trading policy on investors or another policy reasonably designed to deter disruptive short-term trading in Fund shares, and/or (ii) data regarding transactions by investors in the fund-of-funds or asset allocation program, for periods and on a frequency determined by the Fund and Distributor, so that the Fund can monitor compliance by such investors with the trading limitations of the Fund or the fund-of-funds or asset allocation program.

Trade Activity Monitoring. Trading activity is monitored selectively on a daily basis in an effort to detect excessive short-term trading activities. If each Fund or the Distributor believes that a shareholder or financial intermediary has engaged in market timing or other excessive, short-term trading activity, it may, in its discretion, request that the shareholder or financial intermediary stop such activities or refuse to process purchases or exchanges in the accounts. In its discretion, the Fund or the Distributor may restrict or prohibit transactions by such identified shareholders or intermediaries. In making such judgments, the Funds and the Distributor seek to act in a manner that they believe is consistent with the best interests of all shareholders. The Funds and the Distributor also reserve the right to notify financial intermediaries of the shareholder’s trading activity.

Accounts Held by Financial Intermediaries. The ability of each Fund and the Distributor to monitor trades that are placed by omnibus or other nominee accounts is more limited in those instances in which the financial intermediary maintains the record of each Fund’s underlying beneficial owners. In general, each Fund and the Distributor will review trading activity at the omnibus account level. If a Fund and the Distributor detect suspicious activity, they may request and receive personal identifying information and transaction histories for some or all underlying shareholders (including plan participants) to determine whether such shareholders have engaged in market timing or other excessive, short-term trading activity. If a Fund believes that a shareholder has engaged in market timing or other excessive, short-term trading activity in violation of the Fund’s policies through an omnibus account, the Fund will attempt to limit transactions by the underlying shareholder which engaged in such trading, although it may be unable to do so. The Fund may also limit or prohibit additional purchases of Fund shares by an intermediary. Investors should not assume the Funds will be able to detect or prevent all market timing or other trading practices that may disadvantage the Funds.

It is the policy of each Fund to pay its shareholders each year, as dividends, substantially all of its net investment income. Each Fund expects to distribute substantially all net realized long- and short-term capital gains annually, after applying any available capital loss carryovers. To the extent permitted by law, the Board of Trustees may adopt a different schedule as long as payments are made at least annually.

If you do not select an option when you open your account, all distributions will be reinvested.

Except where noted, the discussion below addresses only the U.S. federal income tax consequences of an investment in a Fund and does not address any non-U.S., state, or local tax consequences.

Each Fund intends to meet all requirements under Subchapter M of the Internal Revenue Code of 1986, as amended, (the “Code”), necessary to qualify for treatment as a “regulated investment company” and thus does not expect to pay any federal income tax on income and capital gains that are timely distributed to shareholders.

Taxation of Fund Distributions. For federal income tax purposes, distributions of investment income are generally taxable as ordinary income. Taxes on distributions of capital gains are determined by how long a Fund owned the investments that generated them, rather than how long a shareholder has owned his or her shares. Distributions attributable to the excess of net long-term capital gains from the sale of investments a Fund owned for more than one year over net short-term capital losses and that are properly designated by a Fund as capital gain dividends (“Capital Gain Dividends”) will generally be taxable to a shareholder receiving such distributions as long-term capital gain. Distributions attributable to the excess of net short-term capital gains from the sale of investments that a Fund owned for one year or less over net long-term capital losses will be taxable as ordinary income.

For taxable years beginning before January 1, 2011, distributions of investment income designated by a Fund as derived from “qualified dividend income” are taxed at the rates applicable to long-term capital gain, provided holding period and other requirements are met at both the shareholder and Fund levels. The Funds do not expect a significant portion of their distributions to be derived from qualified dividend income.

For taxable years beginning before January 1, 2011 long-term capital gain rates applicable to individuals have been temporarily reduced, in general, to 15%, with lower rates applying to taxpayers in the 10% and 15% brackets. For more information, see the Statement of Additional Information, under “Distributions and Taxes.”

Dividends and distributions declared by a Fund in October, November or December of one year and paid in January of the next year generally are taxable in the year in which the distributions are declared, rather than the year in which the distributions are received. Fund distributions are taxable whether shareholders receive them in cash or in additional shares. In addition, fund distributions are taxable to shareholders even if they are paid from income or gains earned by

the Fund before a shareholder’s investment (and thus were included in the price the shareholder paid for his or her shares). Such distributions are likely to occur in respect of shares purchased at a time when the Fund’s net asset value reflects gains that are either unrealized or realized but not distributed.

Distributions by a Fund to retirement plans and other investors that qualify for tax-exempt treatment under federal income tax laws generally will not be taxable. Special tax rules apply to investments through such retirement plans. If an investment is through such a plan, the investor should consult a tax adviser to determine the suitability of a Fund as an investment through such a plan and the tax treatment of distributions (including distributions of amounts attributable to an investment in a Fund) from such a plan.

A redemption, sale or exchange of Fund shares (including an exchange of Fund shares for shares of another Natixis or Loomis Sayles Fund) is a taxable event and will generally result in recognition of gain or loss. Gain or loss, if any, recognized by a shareholder on a redemption, sale, exchange or other disposition of Fund shares will generally be treated as long-term capital gain or loss if the shareholder held the shares for more than one year, and as short-term capital gain or loss if the shareholder held the shares for one year or less, assuming in each case that the shareholder held the shares as capital assets. Short-term capital gains are generally taxed at the rates applicable to ordinary income. Any loss realized upon a disposition of shares held for six months or less will be treated as long-term, rather than short-term, capital loss to the extent of any Capital Gain Dividends received by the shareholder with respect to the shares. The deductibility of capital losses is subject to limitations.

Taxation of Certain Fund Investments. Each Fund’s investments in foreign securities may be subject to foreign withholding and other taxes. In that case, the Fund’s yield on those securities would be decreased. Shareholders generally will not be entitled to claim a credit or deduction with respect to foreign taxes incurred by a Fund. In addition, a Fund’s investments in foreign securities and foreign currencies may be subject to special tax rules that have the effect of increasing or accelerating the Fund’s recognition of ordinary income and may affect the timing or amount of a Fund’s distributions.

A Fund’s investments in certain debt obligations and REITs may cause that Fund to recognize taxable income in excess of the cash generated by such obligations. Thus, a Fund could be required to liquidate investments, including at times when it is not advantageous to do so, in order to satisfy its distribution requirements.

A Fund may at times purchase debt instruments at a discount from the price at which they were originally issued, especially during periods of rising interest rates. For federal income tax purposes, some or all of this market discount will, when recognized as income by a Fund, be included in such Fund’s ordinary income, and will be taxable to shareholders as such when it is distributed.

Non-U.S. Shareholders. Capital Gain Dividends generally will not be subject to withholding. Dividends (other than Capital Gain Dividends) paid to a shareholder that is not a “U.S. person” within the meaning of the Code (a “Foreign Person”) are subject to withholding of U.S. federal income tax at a rate of 30% (or lower applicable treaty rate).

In certain circumstances, it is also possible that dividends or distributions paid to Foreign Persons that are attributable to gains from the sale or exchange of U.S. real property interests may be subject to withholding of U.S. federal income tax. For further information, Foreign Persons should consult the SAI.

Backup Withholding. Each Fund is required in certain circumstances to apply backup withholding on taxable dividends, redemption proceeds and certain other payments that are paid to any shareholder (including a shareholder who is neither a citizen nor a resident of the U.S.) if the shareholder does not furnish the Fund certain information and certifications or the shareholder is otherwise subject to backup withholding. The backup withholding rate is 28% for amounts paid on or before December 31, 2010 and will be 31% for amounts paid after December 31, 2010. Backup withholding will not, however, be applied to payments that have been subject to the 30% withholding tax on shareholders who are neither citizens nor residents of the United States.

Please see the SAI for additional information on the federal income tax consequences of an investment in a Fund.

You should consult your tax adviser for more information on your own tax situation, including possible federal, state, local, foreign or other applicable taxes.

The financial highlights table below is intended to help you understand each Fund’s financial performance since inception. Certain information reflects financial results for a single Fund share. The total returns represent the rate that an investor would have earned or lost on an investment in each Fund, assuming reinvestment of all dividends and distributions. This information has been audited by [ ], an independent registered public accounting firm, whose report, along with the Funds’ financial statements, is included in the Funds’ annual report to shareholders. The annual report is incorporated by reference into the SAI and both are available free of charge upon request from the Distributor.

If you would like more information about the Funds, the following documents are available free upon request:

Provide additional information about each Fund’s investments. Each report includes a discussion of the market conditions and investment strategies that significantly affected the Funds’ performance during the last fiscal year.

Provides more detailed information about the Funds and their investment limitations and policies. The SAI has been filed with the SEC and is incorporated into this Prospectus by reference.

To order a free copy of the Funds’ annual or semiannual reports or their SAIs, or to make shareholder inquiries generally, contact your financial representative, or Loomis Sayles at 800-633-3330. The Funds’ annual and semiannual reports and SAI are available on the Funds’ website at www.loomissayles.com.

Information about the Funds, including their reports and SAIs, can be reviewed and copied at the Public Reference Room of the SEC in Washington, D.C. Text-only copies of the Funds’ reports and SAIs are available free from the EDGAR Database on the SEC’s Internet site at: www.sec.gov. Copies of this information may also be obtained, after paying a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the SEC’s Public Reference Section, Washington, D.C. 20549-0102.

Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-202-551-8090.

A description of the Funds’ policies and procedures with respect to the disclosure of each Fund’s portfolio securities is available in the Funds’ SAI.

Natixis Distributors, L.P. (“Natixis Distributors”), an affiliate of Loomis Sayles, and other firms selling shares of Loomis Sayles Funds are members of the Financial Industry Regulatory Authority (“FINRA”). As a service to investors, FINRA has asked that we inform you of the availability of a brochure on its Public Disclosure Program. The program provides access to information about securities firms and their representatives. Investors may obtain a copy by contacting FINRA at 1-800-289-9999 or by visiting its website at www.FINRA.org.

Natixis Distributors distributes the Natixis Funds, Loomis Sayles Funds, Hansberger International Series and Delafield Fund. If you have a complaint concerning Natixis Distributors or any of its representatives or associated persons, please direct it to Natixis Distributors, L.P. Attn: Director of Compliance, 399 Boylston Street - 12th Floor, Boston, MA 02116 or call us at 617-449-2828.

Loomis, Sayles & Company, L.P., which has been an investment adviser since 1926, is the investment adviser of the Funds.

Investment Objective The Fund’s investment objective is high total investment return through a combination of current income and capital appreciation. The Fund’s investment objective may be changed without shareholder approval.

Principal Investment Strategies Under normal circumstances, the Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in fixed-income securities. In accordance with applicable Securities and Exchange Commission (“SEC”) requirements, the Fund will notify shareholders prior to any change to such policy taking effect. The Fund invests primarily in investment-grade fixed-income securities, although it may invest up to 35% of its assets in lower-quality fixed-income securities (commonly known as “junk bonds”) and up to 20% of its assets in preferred stocks. Lower-quality fixed-income securities are below investment grade quality (i.e., none of the three major rating agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Ratings Group) have rated the securities in one of its top four ratings categories) or, if the security is unrated, determined by Loomis Sayles to be of comparable quality. The Fund may invest in fixed-income securities of any maturity.

In deciding which securities to buy and sell, Loomis, Sayles & Company, L.P. (“Loomis Sayles”) will consider, among other things, the financial strength of the issuer of the security, current interest rates, Loomis Sayles’ expectations regarding general trends in interest rates, and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return of those investments.

Three themes typically drive the Fund’s investment approach. First, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles it believes are improving. Second, the Fund makes significant use of non-market related securities, which are securities that may not have a direct correlation with changes in interest rates. Loomis Sayles believes that the Fund may generate positive returns by having a portion of the Fund’s assets invested in non-market related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, Loomis Sayles analyzes different sectors of the economy and differences in the yields (“spreads”) of various fixed-income securities in an effort to find securities that it believes may produce attractive returns for the Fund in comparison to their risk.

Loomis Sayles generally prefers securities that are protected against calls (early redemption by the issuer).

The fixed-income securities in which the Fund may invest include corporate bonds and other debt securities, U.S. Government securities, commercial paper, zero-coupon securities, mortgage-related securities (including mortgage dollar rolls, stripped mortgage- related securities, and collateralized mortgage obligations) and other asset-backed securities, when-issued securities, real estate investment trusts (“REITs”), Rule 144A securities, structured notes, repurchase agreements and convertible securities. The Fund may engage in options and futures transactions, foreign currency transactions, and swap transactions (including credit default swaps) and other derivative transactions. Loomis Sayles may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

As a temporary defensive measure, the Fund may hold any portion of its assets in cash (U.S. Dollars, foreign currencies or multinational currency units) and/or invest in money market instruments or high quality debt securities as Loomis Sayles deems appropriate. The Fund may miss certain investment opportunities if it uses defensive strategies and thus may not achieve its investment objective.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Equity Securities Risk is the risk that the value of a stock may decline for a number of reasons which relate directly to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

mortgage-backed securities (and other asset-backed securities) has experienced high volatility and a lack of liquidity. As a result, the value of many of these securities has significantly declined. There can be no assurance that these markets will become more liquid or less volatile, and it is possible that the value of these securities could decline further.

A dollar roll involves potential risks of loss that are different from those related to securities underlying the transactions. The Fund may be required to purchase securities at a higher price than may otherwise be available on the open market. There is no assurance that the Fund’s use of cash that it receives from a dollar roll will provide a return that exceeds borrowing costs.

Real Estate Investment Trusts (REITs) Risk is the risk that the value of the Fund’s investments will fall as a result of changes in underlying real estate values, rising interest rates, limited diversification of holdings, higher costs and prepayment risk associated with related mortgages, as well as other risks particular to investments in real estate.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each of the last ten calendar years.¹ The returns for Retail Class and Admin Class shares differ from Institutional Class returns shown in the bar chart to the extent that their respective expenses differ.

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]% ([ ] quarter [ ]), and the Fund’s worst quarter was down [ ]% ([ ] quarter [ ]).

Performance Table The table below shows how the average annual total returns for each class of the Fund (before and after taxes for Institutional Class shares) for the one-year, five-year, ten-year and since inception periods compare to those of the Barclays Capital U.S. Government/Credit Index (formerly known as “Lehman U.S. Government/Credit Index”), an unmanaged index of publicly traded bonds, including U.S. Government bonds, U.S. Treasury securities and corporate bonds. You may not invest directly in an index. The Fund’s total returns reflect its expenses on a class-by-class basis. Institutional Class returns have also been calculated to reflect returns after taxes on distributions only and also return after taxes on distributions and sale of Fund shares. The Barclays Capital U.S. Government/Credit Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

Investment Objective The Fund’s investment objective is high total investment return through a combination of high current income and capital appreciation. The Fund’s investment objective may be changed without shareholder approval.

Principal Investment Strategies The Fund will normally invest at least 80% of its net assets (plus any borrowings made for investment purposes) in fixed-income securities. In accordance with applicable SEC requirements, the Fund will notify shareholders prior to any change to such policy taking effect. The Fund invests primarily in investment-grade fixed-income securities worldwide, although it may invest up to 20% of its assets in lower-quality fixed-income securities (commonly known as “junk bonds”). Lower-quality fixed-income securities are below investment grade quality (i.e., none of the three major rating agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Ratings Group) have rated the securities in one of its top four rating categories) or, if the security is unrated, determined by Loomis Sayles to be of comparable quality. Securities held by the Fund may be denominated in any currency and may be issued by issuers located in countries with emerging securities markets. The Fund may invest in fixed-income securities of any maturity. The Fund may also invest in foreign currencies and may engage in other foreign currency transactions for investment or hedging purposes.

In deciding which securities to buy and sell, Loomis Sayles will consider, among other things, the stability and volatility of a country’s bond markets, the financial strength of the issuer, current interest rates and Loomis Sayles’ expectations regarding general trends in interest rates.

Three themes typically drive the Fund’s investment approach. First, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles it believes are improving. Second, Loomis Sayles analyzes political, economic, and other fundamental factors and combines this analysis with a comparison of the yield spreads of various fixed-income securities in an effort to find securities that it believes may produce attractive returns for the Fund in comparison to their risk. Third, if a security that is believed to be attractive is denominated in a foreign currency, Loomis Sayles analyzes whether to accept or to hedge the currency risk. In certain instances, Loomis Sayles may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

when-issued securities, Rule 144A securities, structured notes, repurchase agreements, and convertible securities. The Fund may, but is not required to, engage in options and futures transactions and swap transactions (including credit default swaps) and other derivative transactions.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates. The Fund may, but is not required to, hedge its exposure to foreign currencies (including “cross hedging” between two or more foreign currencies) and may invest in foreign currencies as an asset class.

the economy decline over time — the opposite of inflation. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund’s portfolio.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each of the last ten calendar years.¹ The returns for Retail Class shares differ from Institutional Class returns shown in the bar chart to the extent that their expenses differ.

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]% ([ ]quarter [ ])], and the Fund’s worst quarter was down [ ]% ([ ] quarter [ ]).

Performance Table The table below shows how the average annual total returns for each class of the Fund (before and after taxes for Institutional Class shares) for the one-year, five-year, ten-year and since inception periods compare to those of the Barclays Capital Global Aggregate Bond Index (formerly known as “Lehman Global Aggregate Bond Index”), an unmanaged index that covers the most liquid portion of the global investment-grade fixed-rate bond market. You may not invest directly in an index. The Fund’s total returns reflect its expenses on a class-by-class basis. Institutional Class returns have also been calculated to reflect return after taxes on distributions only and return after taxes on distributions and sale of Fund shares. The Barclays Capital Global Aggregate Bond Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

Principal Investment Strategies The Fund will normally invest at least 80% of its net assets (plus any borrowings made for investment purposes) in inflation-protected securities. In accordance with applicable SEC requirements, the Fund will notify shareholders prior to any change to such policy taking effect. The emphasis will be on debt securities issued by the U.S. Treasury (Treasury Inflation-Protected Securities, or TIPS). The principal value of these securities is periodically adjusted according to the rate of inflation, and repayment of the original bond principal upon maturity is guaranteed by the U.S. Government.

In deciding which securities to buy and sell, Loomis Sayles will consider, among other things, Loomis Sayles’ expectations regarding general trends in interest rates and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return on those investments.

The Fund may invest in other securities, including but not limited to, inflation-protected debt securities issued by U.S. Government agencies and instrumentalities other than the U.S. Treasury, by other entities such as corporations and foreign governments, and by foreign issuers. The Fund may also invest in nominal (i.e., non-inflation protected) treasury securities, corporate bonds, Rule 144A securities, structured notes, asset-backed securities, and mortgage-related securities, including mortgage dollar rolls, and up to 10% of its assets in lower-quality fixed-income securities (commonly known as “junk bonds”). Lower-quality fixed-income securities are below investment grade quality (i.e., none of the three major rating agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Ratings Group) have rated the securities in one of its top four ratings categories) or, if the security is unrated, determined by Loomis Sayles to be of comparable quality. The Fund may invest in fixed-income securities of any maturity. The Fund may also engage in futures transactions and foreign currency transactions. Loomis Sayles may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged. The Fund may also invest in swaps (including credit default swaps) and other derivatives.

The Fund may engage in active and frequent trading of securities. Frequent trading may produce high transaction costs and a high level of taxable capital gains, which may lower the Fund’s return.

As a temporary defensive measure, the Fund may hold any portion of its assets in cash and/or invest in money market instruments or high quality debt securities as Loomis Sayles deems appropriate. The Fund may miss certain investment opportunities if it uses defensive strategies and thus may not achieve its investment objective.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Focused Investment Risk is the Fund’s portfolio is not as diversified as some of the other Funds’ portfolios, which means that the Fund generally invests more of its assets in a smaller number of issuers. As a result, changes in the value of a single security may have a more significant effect on the Fund’s net asset value.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each of the last ten calendar years.¹

Performance Table The table below shows how the average annual total returns for Institutional Class shares (before and after taxes) for the one-year, five-year, ten-year and since inception periods compare to those of the Barclays Capital U.S. Treasury Inflation Protected Securities Index (formerly known as “Lehman U.S. Treasury Inflation Protected Securities Index”), an unmanaged index that measures the performance of the inflation protected securities issued by the U.S. Treasury. You may not invest directly in an index. The Fund’s returns have also been calculated to reflect return after taxes on distributions only and return after taxes on distributions and sale of Fund shares. The Barclays Capital U.S. Treasury Inflation Protected Securities Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

The following tables describe the fees and expenses that you may pay if you buy and hold shares of a Fund.

ANNUAL FUND OPERATING EXPENSES (expenses that are deducted from fund assets, as a percentage of average daily net assets)

Loomis Sayles will be permitted to recover, on a class by class basis, expenses it has borne through the undertakings described above to the extent that a Fund’s expenses in later periods fall below the annual rates set forth in the relevant undertaking. A Fund will not be obligated to pay any such deferred fees and expenses more than one year after the end of the fiscal year in which the fee and expense was deferred.

Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

the Funds’ website at www.loomissayles.com (click on “Investor Type,” “Individual Investors” and then “Holdings”). These holdings will remain accessible on the website until each Fund files its Form N-CSR or Form N-Q with the SEC for the period that includes the date of the information. In addition, a list of each Fund’s top 10 holdings as of the month-end is generally available within 5 days after the month-end on the Funds’ website at www.loomissayles.com (click on “Investor Type,” “Individual Investors,” select the name of the Fund whose holdings you wish to view and then “Portfolio”). Please see the back cover of this Prospectus for more information on obtaining a copy of a Fund’s current annual or semiannual report.

Each Fund may borrow money for temporary or emergency purposes in accordance with its investment restrictions.

Because the Funds may invest in lower-quality fixed-income securities (commonly known as “junk bonds”), the Funds are subject to greater credit risk and market risk than a fund that invests in higher-quality fixed-income securities. Lower-rated fixed-income securities are considered predominantly speculative with respect to the ability of the issuer to make timely principal and interest payments.

The Funds’ investment in securities issued by U.S. Government agencies are subject to security risk. Agencies of the U.S. Government are guaranteed as to the payment of principal and interest of the relevant entity but are not backed by the full faith and credit of the U.S. Government. An event affecting the guaranteeing entity could adversely affect the payment of principal or interest or both on the security, and therefore, these types of securities should be considered to be riskier than U.S. Government securities.

The Funds’ investments in fixed-income securities issued in connection with corporate restructurings by highly-leveraged issuers or in fixed-income securities that are not current in the payment of interest or principal (i.e., in default) will be subject to greater credit risk.

The Funds’ investment in foreign securities are subject to increased credit risk because, for example, of the difficulties of requiring foreign entities to honor their contractual commitments and because a number of foreign governments and other issuers are already in default.

This is the risk that fluctuations in exchange rates between the U.S. dollar and foreign currencies, or between two or more foreign currencies, may cause the value of a Fund’s investments to decline. The Funds are subject to currency risk because they may invest in securities or other instruments denominated in, or receive revenues in, foreign currency are subject to currency risk.

countries and/or impose additional taxes on foreign investors. Certain emerging market countries may also restrict investment opportunities in issuers in industries deemed important to national interests.

Emerging market countries may require governmental approval for the repatriation of investment income, capital or proceeds of sale of securities by foreign investors. In addition, if a deterioration occurs in an emerging market country’s balance of payments, the country could impose temporary restrictions on foreign capital remittances. A Fund could be adversely affected by delays in, or a refusal to grant, any required governmental approval for repatriation of capital, as well as by the application to a Fund of any restrictions on investments. Investing in local markets in emerging market countries may require a Fund to adopt special procedures, seek local governmental approvals or take other actions, each of which may involve additional costs to a Fund.

This is the risk that a Fund that invests a greater percentage of its assets in a particular issuer or a small number of industries may have more risk compared with other mutual funds. Changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund’s net asset value.

This is the risk associated with investments in issuers located or that do business in foreign countries. A Fund’s investments in foreign securities may be less liquid and may experience more rapid and extreme changes in value than investments in securities of U.S. companies.

The securities markets of many foreign countries are relatively small, with a limited number of issuers and a small number of securities. In addition, foreign companies often are not subject to the same degree of regulation as U.S. companies. Reporting, accounting, and auditing standards of foreign countries differ, in some cases significantly, from U.S. standards. Among other things, nationalization, expropriation or confiscatory taxation, currency blockage, political changes, or diplomatic developments can cause the value of a Fund’s investments in a foreign country to decline. In the event of nationalization, expropriation, or other confiscation, a Fund could lose its entire foreign investment.

A Fund that invests in emerging markets may face greater foreign risk since emerging markets countries may be more likely to experience political and economic instability.

Even Funds that generally invest a significant portion of their assets in high-quality fixed-income securities are subject to interest rate risk. Interest rate risk is greater for funds that generally invest a significant portion of their assets in lower-quality fixed-income securities (commonly known as “junk bonds”) or comparable unrated securities. Interest rate risk also is greater for Funds that generally invest in fixed-income securities with longer maturities or durations than for Funds that invest in fixed-income securities with shorter maturities or durations.

Interest rate risk is compounded for Funds when they invest a significant portion of their assets in mortgage-related or asset-backed securities because the value of mortgage-related and asset-backed securities generally is more sensitive to changes in interest rates than other types of fixed-income securities. When interest rates rise, the maturities of mortgage-related and asset-backed securities tend to lengthen, and the value of these securities decreases more significantly than the value of other types of securities. In addition, these types of securities are subject to prepayment when interest rates fall, which generally results in lower returns because funds that hold these types of securities must reinvest assets previously invested in these types of securities in fixed-income securities with lower interest rates.

Each Fund also faces increased interest rate risk when it invests in fixed-income securities paying no current interest (such as zero-coupon securities and principal-only securities), interest-only securities and fixed-income securities paying non-cash interest in the form of other fixed-income securities, because the prices of those types of securities tend to react more to changes in interest rates.

The value of a Fund’s investments may decline for a number of reasons which directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services.

Liquidity risk exists when particular investments are difficult to purchase or sell, possibly preventing a Fund from selling these illiquid securities at the price or at the time desired. Liquidity issues could also make it difficult to value a Fund’s investments, which could also negatively impact net asset value. Derivatives and securities that involve substantial interest rate or credit risk tend to involve greater liquidity risk. In addition, liquidity risk tends to increase to the extent a Fund invests in securities whose sale may be restricted by law or by contract, such as Rule 144A securities.

Lower-quality fixed-income securities, also known as “junk bonds,” are below investment grade quality and may be considered speculative with respect to the issuer’s continuing ability to make principal and interest payments. To be considered below investment grade quality, none of the three major rating agencies (Moody’s Investors Services, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Rating Group) must have rated the security in one of their respective top four rating categories at the time a Fund acquires the security or, if the security is unrated, Loomis Sayles must have determined it to be of comparable quality. Analysis of the creditworthiness of issuers of lower-rated securities may be more complex than for issuers of higher-quality debt securities, and the Fund’s ability to achieve its investment objectives may, to the extent the Fund invests in lower-rated securities, be more dependent upon Loomis Sayles’ credit analysis than would be the case if the Fund were investing in higher-quality securities. The issuers of these securities may be in default or have a currently identifiable vulnerability to default on their payments of principal and interest, or may

otherwise be subject to present elements of danger with respect to payments of principal or interest. However, a Fund will not invest in securities that are in default as to payment of principal and interest at the time of purchase.

Lower-rated securities may be more susceptible to real or perceived adverse economic and competitive industry conditions than higher grade securities. Yields on lower-rated securities will fluctuate. If the issuer of lower-rated securities defaults, a Fund may incur additional expenses to seek recovery.

The secondary markets in which lower-rated securities are traded may be less liquid than the market for higher grade securities. A lack of liquidity in the secondary trading markets could adversely affect the price at which the Fund could sell a particular lower-rated security when necessary to meet liquidity needs or in response to a specific economic event, such as a deterioration in the creditworthiness of the issuer, and could adversely affect and cause large fluctuations in the net asset value of a Fund’s shares. Adverse publicity and investor perceptions may decrease the values and liquidity of high yield securities generally.

It is reasonable to expect that any adverse economic conditions could disrupt the market for lower-rated securities, have an adverse impact on the value of such securities, and adversely affect the ability of the issuers of such securities to repay principal and pay interest thereon. New laws and proposed new laws may adversely impact the market for lower-rated securities.

Management risk is the risk that Loomis Sayles’ investment techniques could fail to achieve a Fund’s objective and could cause your investment in a Fund to lose value. Each Fund is subject to management risk because each Fund is actively managed by Loomis Sayles. Loomis Sayles will apply its investment techniques and risk analyses in making investment decisions for each Fund, but there can be no guarantee that Loomis Sayles’ decisions will produce the desired results. For example, securities that Loomis Sayles expects may appreciate in value may in fact decline. Similarly, in some cases derivative and other investment techniques may be unavailable or Loomis Sayles may determine not to use them, even under market conditions where their use could have benefited a Fund.

conditions, such as changes in interest rates or currency exchange rates. In addition, a company’s securities generally pay dividends only after the company makes required payments to holders of its bonds or other debt. For this reason, the value of the stock will usually react more strongly than bonds and other fixed-income securities to actual or perceived changes in the company’s financial condition or prospects. Market risk tends to be greater when a Fund invests in fixed-income securities with longer maturities.

A mortgage dollar roll involves the sale of a security by a Fund and its agreement to repurchase the instrument at a specified time and price, and may be considered a form of borrowing for some purposes. A Fund will designate assets determined to be liquid in an amount sufficient to meet its obligations under the transactions. A dollar roll involves potential risks of loss that are different from those related to the securities underlying the transactions. A Fund may be required to purchase securities at a higher price than may otherwise be available on the open market. Since the counterparty in the transaction is required to deliver a similar, but not identical, security to a Fund, the security that a Fund is required to buy under the dollar roll may be worth less than an identical security. There is no assurance that a Fund’s use of the cash that it receives from a dollar roll will provide a return that exceeds borrowing costs.

The real estate industry is particularly sensitive to economic downturns. Securities of companies in the real estate industry, including REITs, are sensitive to factors such as changes in real estate values, property taxes, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents, and the management skill and creditworthiness of the issuer. Companies in the real estate industry may also be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or securing mortgage loans held by the REIT. REITs are dependent upon cash flow from their investments to repay financing costs and also on the ability of the REITs’ managers. The Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund. REITs are also subject to the possibilities of failing to qualify for tax-free pass-through of income under the Internal Revenue Code of 1986, as amended (the “Code”), and failing to maintain their exemptions from registration under the Investment Company Act of 1940 (the “1940 Act”).

REITs may have limited financial resources, may trade less frequently and in a limited volume, and may be subject to more abrupt or erratic price movements than more widely-held securities.

A Fund’s investment in a REIT may require the Fund to accrue and distribute income not yet received or may result in the Fund making distributions that constitute a return of capital to Fund shareholders for federal income tax purposes. In addition, distributions by a Fund from REITs will not qualify for the corporate dividends-received deduction, or, generally, for treatment as qualified dividend income.

Each Fund may lend a portion of its portfolio securities to brokers, dealers, and other financial institutions, provided that a number of conditions are satisfied, including that the loan is fully collateralized. Please see “Investment Strategies” in the SAI for details. When a Fund lends portfolio securities, its investment performance will continue to reflect changes in the value of the securities loaned, and the Fund will also receive a fee or interest on the collateral. Securities lending involves the risk of loss of rights in the collateral or delay in recovery of the collateral if the borrower fails to return the security loaned or becomes insolvent. In addition, any investment of cash collateral is generally at the sole risk of the Funds. Any income or gains and losses from investing and reinvesting any cash collateral delivered by a borrower pursuant to a loan are generally at the Fund’s risk, and to the extent any such losses reduce the amount of cash below the amount required to be returned to the borrower upon the termination of any loan, the Fund may be required by the securities lending agent to pay or cause to be paid to such borrower an amount equal to such shortfall in cash, possibly requiring it to liquidate other portfolio securities to satisfy its obligations. A Fund may pay lending fees to the party arranging the loan.

currencies, one or more securities or a securities or commodities index. A structured note may be positively or negatively indexed. For example, its principal amount and/or interest rate may increase or decrease if the value of the reference instrument increases, depending upon the terms of the instrument. The change in the principal amount payable with respect to, or the interest rate of, a structured note may be a multiple of the percentage change (positive or negative) in the value of the underlying reference instrument or instruments. Structured notes can be used to increase a Fund’s exposure to changes in the value of assets or to hedge the risks of other investments that a Fund holds.

Management and Advisors, L.P., AlphaSimplex Group, LLC, BlackRock Investment Management, LLC (“BlackRock”), Dreman Value Management, LLC (“Dreman”), Gateway Investment Advisers, LLC, Hansberger Global Investors, Inc., Harris Associates L.P. and Vaughan Nelson Investment Management, L.P. Each of these advisers and subadvisers (except for BlackRock and Dreman) are subsidiaries of Natixis US and are thus “affiliated persons” under the 1940 Act by reason of being under common control by Natixis US. In addition, because the Funds, and other funds, are advised by firms that are affiliated with one another, they may be considered to be related companies comprising a “group of investment companies” under the 1940 Act. The Central Funds will participate in the credit facility only as lenders. Participation in such an interfund lending program would be voluntary for both borrowing and lending funds, and a Fund would participate in an interfund lending program only if the Board of Trustees determined that doing so would benefit a Fund. Should a Fund participate in such an interfund lending program, the Board of Trustees would establish procedures for the operation of the program by the advisers or an affiliate. The Funds may engage in the transactions described above without further notice to shareholders. The Funds may also make investments in related investment companies to the extent permitted by SEC regulations.

Loomis, Sayles & Company, L.P., located at One Financial Center, Boston, Massachusetts 02111, serves as the investment adviser to the Funds. Loomis Sayles is a subsidiary of Natixis US which is part of Natixis Asset Management Group. Founded in 1926, Loomis Sayles is one of the oldest investment firms in the United States with over $ billion in assets under management as of December 31, 2008. Loomis Sayles is well known for its professional research staff, which is one of the largest in the industry. Loomis Sayles makes investment decisions for each Fund.

The aggregate advisory fee paid by the Funds during the fiscal year ended September 30, 2008 as a percentage of the Funds’ average daily net assets were:

The following persons have had primary responsibility for the day-to-day management of each indicated Fund’s portfolio since the date stated below. Associate portfolio managers are actively involved in formulating the overall strategy for the Funds they manage but are not the primary decision makers. Each portfolio manager has been employed by Loomis Sayles for at least five years.

Kenneth M. Buntrock has served as portfolio manager of the Loomis Sayles Global Bond Fund since September 2000. Mr. Buntrock, Vice President of Loomis Sayles, began his investment career in 1974 and joined Loomis Sayles in 1997. Mr. Buntrock holds the designation of Chartered Financial Analyst. He received a B.A. from Pennsylvania State University, an M.B.A. from the University of Pittsburgh and has over 33 years of investment experience.

Matthew J. Eagan has served as an associate portfolio manager of the Loomis Sayles Bond Fund since February 2007. Mr. Eagan, Vice President of Loomis Sayles, began his investment career in 1989 and joined Loomis Sayles in 1997. He received a B.A. from Northeastern University and an M.B.A. from Boston University. Mr. Eagan holds the designation of Chartered Financial Analyst and has over 18 years of investment experience.

Daniel J. Fuss has served as a portfolio manager of the Loomis Sayles Bond Fund since its inception in May 1991. Mr. Fuss is Vice Chairman, Director and Managing Partner of Loomis Sayles. He began his investment career in 1958 and joined Loomis Sayles in 1976. Mr. Fuss holds the designation of Chartered Financial Analyst. He received a B.S. and an M.B.A. from Marquette University and has over 49 years of investment experience.

Kathleen C. Gaffney has served as co-portfolio manager of the Loomis Sayles Bond Fund since October 1997. Ms. Gaffney, Vice President of Loomis Sayles, began her investment career in 1984 and joined Loomis Sayles in 1984. Ms. Gaffney holds the designation of Chartered Financial Analyst. She received a B.A. from the University of Massachusetts at Amherst and has over 23 years of investment experience.

John Hyll has served as portfolio manager of the Loomis Sayles Inflation Protected Securities Fund since January 2003. Mr. Hyll, Vice President of Loomis Sayles, began his investment career in 1983 and joined Loomis Sayles in 1987. Mr. Hyll received a B.A. and an M.B.A. from Baldwin-Wallace College and has over 24 years of investment experience.

David W. Rolley has served as portfolio manager of the Loomis Sayles Global Bond Fund since September 2000. Mr. Rolley, Vice President of Loomis Sayles, began his investment career in 1980 and joined Loomis Sayles in 1994. Mr. Rolley holds the designation of Chartered Financial Analyst. He received a B.A. from Occidental College, studied graduate economics at the University of Pittsburgh and has over 27 years of investment experience.

Clifton V. Rowe has served as portfolio manager of the Loomis Sayles Inflation Protected Securities Fund since January 2003. Mr. Rowe, Vice President of Loomis Sayles, began his investment career in 1992 and joined Loomis Sayles in 1992. Mr. Rowe holds the designation of Chartered Financial Analyst. He received a B.B.A. from James Madison University, an M.B.A. from the University of Chicago and has over 15 years of investment experience

Lynda L. Schweitzer has served as portfolio manager of the Loomis Sayles Global Bond Fund since February 2007. Ms. Schweitzer, Vice President of Loomis Sayles, began her investment career in 1986 and joined Loomis Sayles in 2001. Ms. Schweitzer holds the designation of Chartered Financial Analyst. She received a B.A. from the University of Rochester, an M.B.A. from Boston University and has over 21 years of investment experience.

Elaine M. Stokes has served as an associate portfolio manager of the Loomis Sayles Bond Fund since February 2007. Ms. Stokes, Vice President of Loomis Sayles, began her investment career in 1987 and joined Loomis Sayles in 1988. She received a B.S. from St. Michael’s College and has over 20 years of investment experience.

Please see the SAI or information on Portfolio Manager compensation, other accounts under management by the Portfolio Managers and the Portfolio Managers’ ownership of securities in the Funds.

For the Retail and Admin Classes of the Funds, the Funds offering those classes have adopted distribution plans under Rule 12b-1 of the 1940 Act that allow the Funds to pay fees for the sale and distribution of Retail and Admin Class shares and for services provided to shareholders. This 12b-1 fee currently is 0.25% of a Fund’s average daily net assets attributable to the shares of a particular Class. Because distribution and service (12b-1) fees are paid out of the Funds’ assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of sales charges and service fees.

Admin Class shares of Loomis Sayles Bond Fund are offered exclusively through intermediaries, who will be the record owners of the shares. Admin Class shares may pay an administrative services fee at an annual rate of up to 0.25% of the average daily net assets attributable to Admin Class shares to securities dealers or financial intermediaries for providing personal service and account maintenance for their customers who hold these shares.

Natixis Distributors, L.P. (the “Distributor”), on behalf of Loomis Sayles, may pay certain broker-dealers and financial intermediaries whose customers are existing shareholders of the Funds a continuing fee at an annual rate of up to 0.35% of the value of Fund shares held for those customers’ accounts, although this continuing fee is paid by the Distributor, on behalf of Loomis Sayles, out of its own assets and is not assessed against the Fund.

The Distributor, the Funds’ adviser and their respective affiliates may, out of their own resources, which generally come directly or indirectly from fees paid by the Funds, make payments in addition to the payments described in this section to dealers and other financial intermediaries that satisfy certain criteria established from time to time by the Distributor. Payments may vary based on sales, the amount of assets a dealer’s or intermediary’s clients have invested in the Funds, and other factors. These payments may also take the form of sponsorship of seminars or informational meetings or payments for attendance by persons associated with a dealer or intermediary at informational meetings. The Distributor and its affiliates may also make payments for recordkeeping and other transfer agency-related services to dealers and intermediaries that sell Fund shares.

payments may result in the Funds’ receiving certain marketing or service advantages that are not generally available to mutual funds that do not make such payments, including placement on a sales list, including a preferred or select sales list, or in other sales programs. Please see the SAI for additional information about payments made by the Distributor and its affiliates to dealers and other financial intermediaries. Please also contact your dealer or financial intermediary for details about payments it may receive.

Net asset value (“NAV”) is the price of one share of a Fund without a sales charge and is calculated each business day using this formula:

The net asset value of Fund shares is determined pursuant to policies and procedures approved by the Fund’s Board of Trustees as summarized below:

Equity securities. Last sale price on the exchange or market where primarily traded or if there is no reported sale during the day, the closing bid price.

Short-term obligations (remaining maturity of 60 days or less). Amortized cost (which approximates market value).

Securities traded on foreign exchanges. Market price on the non-U.S. exchange, unless a Fund believes that an occurrence after the close of that exchange will materially affect the security’s value. In that case, the security may be fair valued at the time the Fund determines its net asset value by or pursuant to procedures approved by the Board of Trustees. When fair valuing securities, the Funds may, among other things, use modeling tools or other processes that may take into account factors such as securities market activity and/or significant events that occur after the close of the local market and before the time a Fund’s net asset value is calculated.

Options. The Funds generally value exchange-traded options at the average of the closing bid and asked quotations.

Credit default swaps. Market value based on prices supplied by a pricing service, if available, or quotations obtained from broker dealers.

Foreign Currency Forward Contracts. Interpolated prices from information provided by an independent pricing service.

All other securities. Fair market value as determined by the adviser of the Fund pursuant to procedures approved by the Board of Trustees.

(which is the amount that a Fund might reasonably expect to receive from a current sale of the security in the ordinary course of business). A Fund may also value securities at fair value or estimate their value pursuant to procedures approved by the Board of Trustees in other circumstances such as when extraordinary events occur after the close of the relevant market but prior to the close of the NYSE. This may include situations relating to a single issuer (such as a declaration of bankruptcy or a delisting of the issuer’s security from the primary market on which it has traded) as well as events affecting the securities markets in general (such as market disruptions or closings and significant fluctuations in U.S. and/or foreign markets). Fair value pricing may require subjective determinations about the value of a security, and fair values used to determine a Fund’s net asset value may differ from quoted or published prices, or from prices that are used by others, for the same securities. In addition, the use of fair value pricing may not always result in adjustments to the prices of securities held by a Fund.

Loomis Sayles Funds Website. You can access our website at www.loomissayles.com to perform transactions (purchases, redemptions or exchanges), to review your account information, change your address, order duplicate statements or tax forms, or to obtain a prospectus, an SAI, an application or periodic reports.

Loomis Sayles Automated Voice Response System. You have access to your account 24 hours a day by calling Loomis Sayles’ automated voice response system at 800-633-3330, option 1. Using this customer service option you may review your account balance and Fund prices, order duplicate statements, order duplicate tax forms, obtain distribution and performance information and obtain wiring instructions.

Through a financial adviser. Your financial adviser will be responsible for furnishing all necessary documents to Loomis Sayles Funds. Your financial adviser may charge you for these services. Your adviser must receive your request in proper form before the close of regular trading on the NYSE for you to receive that day’s NAV.

Through a broker-dealer. You may purchase shares of the Funds through a broker-dealer that has been approved by the Distributor which can be contacted at 399 Boylston Street, Boston, MA 02116. Your broker-dealer may charge you a fee for effecting such transactions. Your broker-dealer must receive your request in proper form before the close of regular trading on the NYSE for you to receive that day’s NAV.

Directly from the Fund. Loomis Sayles Funds must receive your purchase request in proper form before the close of regular trading on the NYSE in order for you to receive that day’s NAV.

By mail. You can buy shares of each Fund by submitting a completed application form, which is available online at www.loomissayles.com or by calling Loomis Sayles Funds at 800-633-3330, for along with a check payable to Loomis Sayles Funds for the amount of your purchase to:

After your account has been established, you may send subsequent investments directly to Loomis Sayles Funds at the above addresses. Please include either the investment slip from your account statement or a letter specifying the Fund name, your account number and your name, address and telephone number.

By wire. You also may wire subsequent investments by using the following wire instructions. Your bank may charge a fee for transmitting funds by wire.

By telephone. If you established the electronic transfer privilege on your new account, you can make subsequent investments by calling Loomis Sayles Funds at 800-633-3330. If you did not establish the electronic transfer privilege on your application, you may add the privilege by obtaining an Account Options Form through your financial adviser, by calling Loomis Sayles Funds at 800-633-3330 or by visiting www.loomissayles.com.

By exchange. You may purchase shares of a Fund by exchange of shares of another Fund by sending a signed letter of instruction to Loomis Sayles Funds, by calling Loomis Sayles Funds at 800-633-3330 or by accessing your account online at www.loomissayles.com.

not established a PIN but you have established the electronic transfer privilege from www.loomissayles.com, click on “Account Access” then click on the appropriate user type and then follow the instructions.

Through systematic investing. You can make regular investments of $50 or more per month through automatic deductions from your bank checking or savings account. If you did not establish the electronic transfer privilege on your application, you may add the privilege by obtaining an Account Options Form through your financial adviser, by calling Loomis Sayles Funds at 800-633-3330 or by visiting www.loomissayles.com.

Each Fund sells its shares at the NAV next calculated after the Fund receives a properly completed investment order. The Fund generally must receive your properly completed order before the close of regular trading on the NYSE for your shares to be bought or sold at the Fund’s NAV on that day.

Subject to the approval of the Fund, an investor may purchase Institutional Class shares of a Fund with liquid securities and other assets that are eligible for purchase by the Fund (consistent with the Fund’s investment policies and restrictions) and that have a value that is readily ascertainable in accordance with the Fund’s valuation policies. These transactions will be effected only if Loomis Sayles deems the security to be an appropriate investment for the Fund. Assets purchased by a Fund in such a transaction will be valued in accordance with procedures adopted by the Fund. The Funds reserve the right to amend or terminate this practice at any time.

All purchases made by check should be in U.S. dollars and made payable to Loomis Sayles Funds. Third party checks, starter checks and credit card convenience checks will not be accepted. When you make an investment by check or by periodic account investment, you will not be permitted to redeem that investment until the check has cleared or the shares have been in your account for 15 days.

A Fund may periodically close to new purchases of shares or refuse any order to buy shares if the Fund determines that doing so would be in the best interests of the Fund and its shareholders. See “Restrictions on Buying, Selling and Exchanging Shares” below. Except as otherwise permitted by the Distributor, the Funds will only accept accounts from U.S. citizens with a U.S. address or resident aliens with a U.S. address and a U.S. taxpayer identification number.

reserves the right to refuse to open an account, close an account and redeem your shares at the then current price or take other such steps that the Fund deems necessary to comply with federal regulations if your identity is not verified.

The following table shows the investment minimum for each class of shares of each Fund.

Each Fund’s shares (except Admin Class shares) may be purchased by all types of tax-deferred retirement plans. If you wish to open an individual retirement account (IRA) with a Fund, you may obtain retirement plan forms available online at www.loomissayles.com, or by calling Loomis Sayles Funds at 800-633-3330. Admin Class shares are intended primarily for qualified retirement plans held in an omnibus fashion and are not appropriate for individual investors.

Each subsequent investment must be at least $50. Loomis Sayles Funds reserves the right to waive these minimums in its sole discretion, including for certain retirement plans whose accounts are held on the books of the Funds’ transfer agent in an omnibus fashion. At the discretion of Loomis Sayles, employees and clients of Loomis Sayles, and their respective family members, may purchase shares of the funds offered through this prospectus below the stated minimums. In addition, at the discretion of Natixis Advisors, clients of Natixis Advisors may also purchase shares of the Funds below the stated minimums.

In our continuing effort to reduce your Fund’s expenses and amount of mail that you receive from Loomis Sayles Funds, we will mail only a single copy of prospectuses, proxy statements and financial reports to your household. Additional copies may be obtained by calling 800-633-3330.

This program will continue in effect unless you notify us that you do not want to participate in this combined mailing program. If you wish to receive separate mailings for each Fund you own in the future, please call us at the telephone number above or mail your written request to Loomis Sayles, P.O. Box 219594, Kansas City, MO 64121-9594 and we will resume separate mailings within 30 days.

assessed by the automatic redemption of shares in the account in an amount sufficient to pay the fee. The minimum balance fee does not apply to directly registered accounts that (i) make monthly purchases through systematic investing or (ii) are retirement accounts. If your Fund account falls below $50 the Fund may redeem your remaining shares and send the proceeds to you. Accounts associated with defined contribution plans are excepted from the minimum balance fee and liquidation.

You can redeem shares of each Fund any day the NYSE is open either through your financial advisor or directly from the Fund. Shares purchased by check are redeemable, although each Fund may withhold payment until the purchase check has cleared. If you are redeeming shares that you purchased within the past 15 days by check, telephone ACH or online ACH, your redemption will be delayed until the shares have been in your account for 15 days.

Because large redemptions are likely to require liquidation by a Fund of portfolio holdings, payment for large redemptions may be delayed for up to seven days to provide for orderly liquidation of such holdings. Under unusual circumstances, the Funds may suspend redemptions or postpone payment for more than seven days. Although most redemptions are made in cash, as described in the SAI, each Fund reserves the right to redeem shares in kind.

Redemptions through your financial adviser. Your adviser must receive your request in proper form before the close of regular trading on the NYSE for you to receive that day’s NAV (less any applicable charges). Your adviser will be responsible for furnishing all necessary documents to Loomis Sayles Funds on a timely basis and may charge you for his or her services.

Redemptions through your broker-dealer. You may redeem shares of the Funds through a broker-dealer that has been approved by the Distributor, which can be contacted at 399 Boylston Street, Boston, MA 02116. Your broker-dealer may charge you a fee for effecting such transaction. Your broker-dealer must receive your request in proper form before the close of regular trading on the NYSE for you to receive that day’s NAV (less any applicable charges). Your redemptions generally will be wired to your broker-dealer on the first business day after your request is received in good order.

Redemptions directly from the Funds. Loomis Sayles Funds must receive your redemption request in proper form before the close of regular trading on the NYSE in order for you to receive that day’s NAV (less any applicable charges). Your redemptions generally will be sent to you via first class mail within three business days after your request is received in good order, although it may take longer.

By mail. Send a signed letter of instruction that includes the name of the Fund, the exact name(s) in which the shares are registered, any special capacity in which you are signing (such as trustee or custodian or on behalf of a partnership, corporation, or other entity), your address, telephone number, account number and the number of shares or dollar amount to be redeemed to the following address:

If you have certificates for the shares you want to sell, you must include them along with completed stock power forms.

All owners of shares must sign the written request in the exact names in which the shares are registered. The owners should indicate any special capacity in which they are signing (such as trustee or custodian or on behalf of a partnership, corporation or other entity).

By exchange. You may sell some or all of your shares of a Fund and use the proceeds to buy shares of another Loomis Sayles Fund by sending a letter of instruction to Loomis Sayles Funds, calling Loomis Sayles Funds at 800-633-3330 or exchanging online at www.loomissayles.com.

By internet. If you have established a Personal Identification Number (PIN), and you have established the electronic transfer privilege, you can redeem shares through your online account at www.loomissayles.com. If you have not established a PIN, but you have established the electronic transfer privilege, click on “Account Access” at www.loomissayles.com, click on the appropriate user type, and then follow the instructions.

By telephone. You may redeem shares by calling Loomis Sayles Funds at 800-633-3330. Proceeds from telephone redemption requests can be wired to your bank account, sent electronically by ACH to your bank account or sent by check in the name of the registered owner(s) to the record address. A wire fee will be deducted from your proceeds. Your bank may charge you a fee to receive the wire.

Retirement shares may not be redeemed by telephone. Please call Loomis Sayles Funds at 800-633-3330 for an IRA Distribution Form, or download the form online at www.loomissayles.com.

The telephone redemption privilege may be modified or terminated by the Funds without notice. Certain of the telephone redemption procedures may be waived for holders of Institutional Class shares.

The maximum value of shares that you may redeem by telephone or internet is $100,000. For your protection, telephone or internet redemption requests will not be permitted if Loomis Sayles Funds has been notified of an address change or bank account information change for your account within the preceding 30 days. Unless you indicate otherwise on your account application, Loomis Sayles Funds will be authorized to accept redemption and transfer instructions by telephone. If you prefer, you can decline telephone redemption and transfer privileges.

Systematic Withdrawal Plan. If the value of your account is $25,000 or more, you can have periodic redemptions automatically paid to you or to someone you designate. Please call 800-633-3330 for more information or to set up a systematic withdrawal plan or visit www.loomissayles.com to obtain an Account Options Form.

By Wire. Before Loomis Sayles Funds can wire redemption proceeds to your bank account, you must provide specific wire instructions to Loomis Sayles Funds in writing. A wire fee will be deducted from the proceeds of each wire.

By ACH. For ACH redemptions, proceeds (less any applicable redemption fee) will generally arrive at your bank within three business days.

Medallion Signature Guarantee. You must have your signature guaranteed by a bank, broker-dealer, or other financial institution that can issue a medallion signature guarantee for the following types of redemptions:

The Funds will only accept medallion signature guarantees bearing the STAMP2000 Medallion imprint. Please note that a notary public cannot provide a medallion signature guarantee. This signature guarantee requirement may be waived by Loomis Sayles Funds in certain cases.

is advised by Natixis Advisors, an affiliate of Loomis Sayles. You may exchange Admin Class shares of your Fund offered through this prospectus, subject to investment minimums, for Admin Class shares of any Loomis Sayles Fund that offers Admin Class shares without paying a sales charge or for Class A shares of Natixis Cash Management Trust. You may exchange Institutional Class shares of your Fund, subject to investment minimums, for Institutional Class shares of any Loomis Sayles Fund that offers Institutional Class shares, for Class Y shares of any Natixis Fund that offers Class Y shares or for Class A shares of Natixis Cash Management Trust. All exchanges are subject to any restrictions described in the applicable Funds’ prospectuses.

You may be unable to hold your shares through the same financial intermediary if you engage in certain share exchanges. You should contact your financial intermediary for further details.

The value of Fund shares that you wish to exchange must meet the investment minimum requirements of the new fund.

You may make an exchange by sending a signed letter of instruction, through your online account at www.loomissayles.com, or by telephone unless you have elected on your account application to decline telephone exchange privileges.

Please remember that an exchange may be a taxable event for federal and/or state income tax purposes, so that you may realize a gain or loss that is subject to income tax.

In certain limited circumstances, you may convert Retail Class shares of your Fund to Institutional Class shares of the same Fund or convert Institutional Class shares of your Fund to Retail Class shares of the same Fund. The value of shares that you wish to convert must meet at least the investment minimum requirements of the new Class. The conversion from one class of shares to another will be based on the respective net asset values of the separate classes on the trade date for the conversion. You will not be charged any redemption fee or exchange fee as a result of the exchange. A conversion between share classes of the same fund is a nontaxable event to the shareholder.

You may convert Retail Class shares of your Fund to Institutional Class shares of the same Fund if you have accumulated shares with a net asset value greater than or equal to the minimum investment amount for Institutional Class shares of that same Fund. You may convert from Institutional Class shares to Retail Class shares only if the investment option or program through which you invest no longer permits the use of Institutional Class shares in that option or program or if you otherwise are no longer able to participate in Institutional Class shares. A conversion into a class of shares is subject to the purchase restrictions of such Class as described in the Fund’s prospectus (see “How to Purchase Shares”).

In order to convert shares, you must complete the Cross Share Exchange Form and return it to Loomis Sayles Funds at the following address:

You can obtain the form by calling 800-633-3330 or by visiting the Funds’ website at www.loomissayles.com. All requests for conversions (including requests for accounts traded through the National Securities Clearing Corporation) must be provided on the Cross Share Exchange Form.

intermediary, such as a broker, bank, investment adviser, recordkeeper for retirement plan participants, or other third party. The preceding are not exclusive lists of activities that the Funds and the Distributor may consider to be “market timing.”

Certain Funds also seek to prevent excessive and disruptive trading practices through the assessment of redemption fees on shares redeemed or exchanged within a given time period. See the section “Redemption Fees” for more information.

Capital gain distributions normally are made annually, but may be made more frequently as deemed advisable by the Funds and as permitted by applicable law. The trustees may change the frequency with which each Fund declares or pays dividends. The table below provides further information about each Fund’s dividend policy.

If you do not select an option when you open your account, all distributions will be reinvested.

Except where noted, the discussion below addresses only the U.S. federal income tax consequences of an investment in a Fund and does not address any non-U.S., state, or local tax consequences.

Taxation of Fund Distributions. For federal income tax purposes, distributions of investment income are generally taxable to Fund shareholders as ordinary income. Taxes on distributions of capital gains are determined by how long a Fund owned the investments that generated them, rather than how long a shareholder has owned his or her shares. Distributions attributable to the excess of net long-term capital gains from the sale of investments the Fund owned for more than one year over net short-term capital losses and that are properly designated by the Fund as capital gain dividends (“Capital Gain Dividends”) will generally be taxable to a shareholder receiving such distributions as long-term capital gain. Distributions attributable to the excess of net short-term capital gains from the sale of investments that the Fund owned for one year or less over net long-term capital losses will be taxable as ordinary income. Distributions by the Fund to retirement plans that qualify for tax-exempt treatment under federal income tax laws generally will not be taxable.

For the taxable years beginning before January 1, 2011, distributions of investment income designated by a Fund as derived from “qualified dividend income” will be taxed at the rates applicable to long-term capital gain, provided holding period and other requirements are met at both the shareholder and Fund levels. The Funds do not expect a significant portion of their distributions to be derived from qualified dividend income.

Fund distributions are taxable whether shareholders receive them in cash or in additional shares. In addition, Fund distributions are taxable to shareholders even if they are paid from income or gains earned by a Fund before a shareholder’s investment (and thus were included in the price the shareholder paid for his or

her shares). Such distributions are likely to occur in respect of shares purchased at a time when the Fund’s net asset value reflects gains that are either unrealized or realized but not distributed.

For taxable years beginning before January 1, 2011, long-term capital gain rates applicable to individuals have been temporarily reduced, in general to 15%, with lower rates applying to taxpayers in the 10% and 15% rate brackets. For more information, see the SAI under “TAXES.”

Redemption, Sale or Exchange of Fund Shares. A redemption, sale or exchange of Fund shares (including an exchange of Fund shares fro shares of another Natixis or Loomis Sayles Fund) is a taxable event and will generally result in recognition of gain or loss. Gain or loss, if any, recognized by a shareholder on a redemption, sale, exchange or other disposition of Fund shares will generally be treated as long-term capital gain or loss if the shareholder held the shares for more than one year, and as short-term capital gain or loss if the shareholder held the shares for one year or less, assuming in each case that the shareholder held the shares as capital assets. Short-term capital gains are generally taxed at the rates applicable to ordinary income. Any loss realized upon a disposition of shares held for six months or less will be treated as long-term, rather than short-term, capital loss to the extent of any Capital Gain Dividends received by the shareholder with respect to the shares. The deductibility of capital losses is subject to limitations.

Taxation of Certain Fund Investments. Each Fund’s investments in foreign securities may be subject to foreign withholding or other taxes. In that case, the Fund’s yield on those securities would be decreased. The Fund generally does not expect shareholders will be entitled to claim a credit or deduction with respect to foreign taxes incurred by a Fund. In addition, a Fund’s investments in foreign securities or foreign currencies may be subject to special tax rules that have the effect of increasing or accelerating the Fund’s recognition of ordinary income and may affect the timing or amount of the Fund’s distributions.

A Fund’s investments in certain debt obligations, mortgage-backed securities, asset-backed securities and derivatives may cause the Fund to recognize taxable income in excess of the cash generated by such obligations. Thus, a Fund could be required at times to liquidate investments, including at times when it is not advantageous to do so, in order to satisfy its distribution requirements.

In addition, a Fund may at times purchase debt instruments at a discount from the price at which they were originally issued, especially during periods of rising interest rates. For federal income tax purposes, some or all of this market discount will, when recognized as income by a Fund, be included in such Fund’s ordinary income and will be taxable to shareholders as such when it is distributed.

Non-U.S. Shareholders. Capital Gain Dividends generally will not be subject to withholding. Dividends other than Capital Gain Dividends paid to a shareholder that is not a “U.S. person” within the meaning of the Code (a “Foreign Person”) generally are subject to withholding of U.S. federal income tax at a rate of 30% (or lower applicable treaty rate). For further information, Foreign Person should consult the SAI.

Backup Withholding. Each Fund is also required in certain circumstances to apply backup withholding on taxable dividends, redemption proceeds and certain other payments that are paid to any shareholder (including a shareholder who is neither a citizen nor a resident of the U.S.) if the shareholder does not furnish to the Funds certain information and certifications or the shareholder is otherwise subject to backup withholding. The backup withholding tax rate is 28% for amounts paid on or before December 31, 2010 and will be 31% for amounts paid after December 31, 2010. Backup withholding will not, however, be applied to payments that have been subject to the 30% withholding tax applicable to shareholders who are neither citizens nor residents of the United States.

Please see the SAI for additional information on the federal income tax consequences of an investment in the Funds.

You should consult your tax adviser for more information on your own tax situation, including possible federal, state, local, foreign or other applicable taxes.

The financial highlights tables are intended to help you understand each Fund’s financial performance for the last five years (or, if shorter, the period of the Fund’s operations). Certain information reflects financial results for a single Fund share. The total returns in the table represent the return that an investor would have earned (or lost) on an investment in a Fund (assuming reinvestment of all dividends and distributions). This information has been audited by [ ], an independent registered public accounting firm, whose report, along with each Fund’s financial statements, is included in the Funds’ annual report to shareholders. The annual report is incorporated by reference into the SAI, both of which are available free of charge upon request from the Distributor.

If you would like more information about the Funds, the following documents are available free upon request:

Provides more detailed information about the Funds and their investment limitations and policies. The SAI has been filed with the SEC and is incorporated into this Prospectus by reference.

Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-202-551-8090.

A description of the Funds’ policies and procedures with respect to the disclosure of each Fund’s portfolio securities is available in the Funds’ SAI.

Loomis, Sayles & Company, L.P., which has been an investment adviser since 1926, is the investment adviser of the Funds.

Investment Objective The Fund’s investment objective is long-term capital growth from investments in common stocks or other equity securities. The Fund’s investment objective may be changed without shareholder approval.

Principal Investment Strategies The Fund normally will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in equity securities of companies with market capitalizations that fall within the capitalization range of the Russell 2000 Index, an index that tracks stocks of 2,000 of the smallest U.S. companies. In accordance with applicable Securities and Exchange Commission (“SEC”) requirements, the Fund will notify shareholders prior to any change to such policy taking effect. The Fund may invest the rest of its assets in companies of any size, including large capitalization companies.

In deciding which securities to buy and sell, Loomis Sayles seeks to identify companies that it believes have distinctive products, technologies, or services; dynamic earnings growth; prospects for high levels of profitability; and solid management. Loomis Sayles typically does not consider current income when making buy/sell decisions.

The Fund may invest any portion of its assets in securities of Canadian issuers and up to 20% of its assets in other foreign securities, including emerging markets securities. The Fund may engage in foreign currency transactions, options and futures transactions, and other derivative transactions and securities lending. Loomis Sayles may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged. The Fund also may invest in Rule 144A securities. The Fund may engage in active and frequent trading of securities. Frequent trading may produce high transaction costs and a high level of taxable capital gains, which may lower the Fund’s return.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Small Capitalization Companies Risk is the risk that the Fund’s investments may be subject to more abrupt price movements, limited markets and less liquidity than investments in larger, more established companies, which could adversely affect the value of the portfolio.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each of the last ten calendar years. The returns for Retail Class shares differ from the Institutional Class returns shown in the bar chart to the extent their respective expenses differ.

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]% ([ ]quarter [ ]), and the Fund’s worst quarter was down [ ]% ([ ] quarter [ ]).

Performance Table The table below shows how the average annual total returns for each class of the Fund (before and after taxes for Institutional Class shares) for the one-year, five-year, ten-year, and since inception periods compare to those of the Russell 2000 Index and the Russell 2000 Growth Index. The Russell 2000 Index is an unmanaged index that consists of the 2,000 smallest companies in the Russell 3000 Index. The Russell 2000 Growth Index is an unmanaged index that measures the performance of those Russell 2000 companies with higher price-to-book ratios and higher forecasted growth values. You may not invest directly in an index. The Fund’s total returns reflect its expenses on a class-by-class basis. Institutional Class returns have also been calculated to reflect return after taxes on distributions only and also return after taxes on distributions and sale of Fund shares. The Russell 2000 Index and the Russell 2000 Growth Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

Loomis Sayles seeks to identify securities of smaller companies that it believes are undervalued by the market. Loomis Sayles will consider, among other things, price-to-earnings, price-to-book and price-to-cash flow ratios. The Fund’s investments may include companies that have suffered significant business problems but are believed by Loomis Sayles to have favorable prospects for recovery. The Fund’s investments may also include companies that are not yet well known to the investment community, but are considered to have favorable fundamental prospects and attractive valuation. Loomis Sayles generally seeks to achieve investment performance by selecting individual stocks it believes are attractive, rather than rotating the Fund’s holdings among various sectors of the economy.

The Fund may invest up to 20% of its assets in securities of foreign issuers, including emerging markets securities. The Fund may engage in foreign currency transactions, options and also may invest in real estate investment trusts (“REITs”), Rule 144A securities, and, to the extent permitted by the Investment Company Act of 1940 and the rules thereunder (the “1940 Act”), investment companies. Loomis Sayles may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each of the last ten calendar years.¹ The returns for Retail Class and Admin Class shares differ from the Institutional Class returns shown in the bar chart to the extent their respective expenses differ.

Performance Table The table below shows how the average annual total returns for each class of the Fund (before and after taxes for Institutional Class shares) for the one-year, five-year, ten-year and since inception periods compare to those of the Russell 2000 Index and the Russell 2000 Value Index. The Russell 2000 Index is an unmanaged index that consists of the 2,000 smallest companies in the Russell 3000 Index. The Russell 2000 Value Index is an unmanaged index that measures the performance of those Russell 2000 companies with lower price-to-book ratios and lower forecasted growth values. You may not invest directly in an index. The Fund’s total returns reflect its expenses on a class-by-class basis. Institutional Class returns have also been calculated to reflect return after taxes on distributions only and also return after taxes on distributions and sale of Fund shares. The Russell 2000 Index and the Russell 2000 Value Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

The following tables describe the fees and expenses that you may pay if you buy and hold shares of a Fund.

ANNUAL FUND OPERATING EXPENSES (expenses that are deducted from fund assets, as a percentage of average daily net assets)

Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

A “snapshot” of each Fund’s investments may be found in each Fund’s annual and semiannual reports. In addition, a list of each Fund’s full portfolio holdings, which is updated monthly after an aging period of at least 30 days, is available on the Funds’ website at www.loomissayles.com (click on “Investor Type,” “Individual Investors” and then “Holdings”). These holdings will remain accessible on the website until each Fund files its Form N-CSR or Form N-Q with the SEC for the period that includes the date of the information. In addition, a list of each Fund’s top 10 holdings as of the month-end is generally available within 5 days after the month-end on the Funds’ website at www.loomissayles.com (click on

“Investor Type,” “Individual Investors,” select the name of the Fund whose holdings you wish to view and then “Portfolio”). Please see the back cover of this Prospectus for more information on obtaining a copy of a Fund’s current annual or semiannual report.

Each Fund may borrow money for temporary or emergency purposes in accordance with its investment restrictions.

A Fund that may invest in lower-quality fixed-income securities (commonly known as “junk bonds”) are subject to greater credit risk and market risk than a Fund that invests in higher-quality fixed-income securities. Lower-rated fixed-income securities are considered predominantly speculative with respect to the ability of the issuer to make timely principal and interest payments.

A Fund that may invest in foreign securities is subject to increased credit risk, for example, because of the difficulties of requiring foreign entities to honor their contractual commitments and because a number of foreign governments and other issuers are already in default.

This is the risk that fluctuations in exchange rates between the U.S. dollar and foreign currencies may cause the value of a Fund’s investments to decline. The Funds are subject to currency risk because they may invest in securities or other instruments denominated in, or receive revenues in, foreign currencies.

Certain Funds may use derivatives, which are financial contracts whose value depends upon or is derived from the value of an underlying asset, reference rate, or index. Examples of derivatives include options, futures, swap transactions, foreign transactions and foreign currency transactions. A Fund may (but are not required to) use derivatives as part of a strategy designed to reduce exposure to other risks, such as risks associated with changes in interest rates or currency risk (“hedging”). The Funds may also use derivatives for leverage, which increases opportunities for gain but also involves greater risk of loss due to leveraging risk, and to earn income, enhance yield, or broaden the Fund’s diversification by gaining exposure to issuers, indices, sectors, currencies and/or geographic regions. This use of derivatives for these purposes entails greater risk than using derivatives solely for hedging purposes.

The value of the Fund’s investments in equity securities is subject to the risks of unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. In addition, the value of stock in the Fund’s portfolio may decline for a number of reasons which relate directly to the issuer. Those reasons may include, among other things, management performance, the effects of financial leverage and reduced demand for a company’s goods and services. Equity securities may include common stocks, preferred stocks, warrants, securities convertible into common or preferred stocks and other equity-like interests in an entity. Equity securities may take the form of stock in corporation, limited partnership interests, interests in limited liability companies, REITs or other trusts and other similar securities.

The securities markets of many foreign countries are relatively small, with a limited number of issuers and a small number of securities. In addition, foreign companies often are not subject to the same degree of regulation as U.S. companies. Reporting, accounting, and auditing standards of foreign countries differ, in some cases significantly, from U.S. standards. Among other things, nationalization, expropriation or confiscatory taxation, currency blockage, political changes, or diplomatic developments can cause the value of a Fund’s investments in a foreign country to decline. In the event of nationalization, expropriation, or other confiscation, a Fund could lose its entire foreign investment.

A Fund that invests in emerging markets may face greater foreign risk since emerging markets countries may be more likely to experience political and economic instability.

Liquidity risk exists when particular investments are difficult to purchase or sell, possibly preventing a Fund from selling these illiquid securities at the price or at the time desired. Liquidity issues could also make it difficult to value a Fund’s investments, which could also negatively impact net asset value. Derivatives and securities that involve substantial interest rate or credit risk tend to involve greater liquidity risk. In addition, liquidity risk tends to increase to the extent a Fund invests in securities whose sale may be restricted by law or by contract, such as Rule 144A securities.

Management risk is the risk that Loomis Sayles’ investment techniques could fail to achieve a Fund’s objective and could cause your investment in a Fund to lose value. Each Fund are subject to management risk because each Fund is actively managed by Loomis Sayles. Loomis Sayles will apply its investment techniques and risk analyses in making investment decisions for each Fund, but there can be no guarantee that Loomis Sayles’ decisions will produce the desired results. For example, securities that Loomis Sayles expects may appreciate in value may in fact decline. Similarly, in some cases derivative and other investment techniques may be unavailable or Loomis Sayles may determine not to use them, even under market conditions where their use could have benefited a Fund.

as decisions made by its management or lower demand for the company’s products or services. A security’s value also may fall because of factors affecting not just the company, but companies in its industry or in a number of different industries, such as increases in production costs. The value of a company’s security also may be affected by changes in financial market or other economic conditions, such as changes in interest rates or currency exchange rates. In addition, a company’s securities generally pay dividends only after the company makes required payments to holders of its bonds or other debt. For this reason, the value of the stock will usually react more strongly than bonds and other fixed-income securities to actual or perceived changes in the company’s financial condition or prospects. Market risk tends to be greater when a Fund invests in fixed-income securities with longer maturities.

Market risk generally is greater for funds that invest substantially in small and medium-sized companies, since these companies tend to be more vulnerable to adverse developments than large companies. IPO securities tend to involve greater market risk than other equity securities due, in part, to public perception and the lack of public information and trading history.

REITs involve certain unique risks in addition to those risks associated with investing in the real estate industry in general (such as possible declines in the value of real estate, lack of availability of mortgage funds, or extended vacancies of property). Equity REITs may be affected by changes in the value of the underlying property owned by the REITs, while mortgage REITs may be affected by the quality of any credit extended. REITs are dependent upon management skills, are not diversified, and are subject to heavy cash flow dependency, risks of default by borrowers, and self-liquidation. REITs are also subject to the possibilities of failing to qualify for tax-free pass-through of income under the Internal Revenue Code of 1986, as amended, and failing to maintain their exemptions from registration under the 1940 Act.

Furthermore, the real estate industry is particularly sensitive to economic downturns. Securities of companies in the real estate industry, including REITs, are particularly sensitive to factors such as changes in real estate values, property taxes, interest rates, cash flows or underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents, and the management skill and creditworthiness of the issuer. Companies in the real estate industry may also be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or securing mortgage loans held by the REIT. A Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund.

REITs may have limited financial resources, may trade less frequently and in a limited volume, and may be subject to more abrupt or erratic price movements than more widely-held securities.

Pursuant to such exemptive relief, the Funds may also borrow and lend money for temporary or emergency purposes directly to and from other Funds through an interfund credit facility. In addition to the Funds and the Central Funds, series of the following mutual fund groups may also be able to participate in the facility: Natixis Funds Trust I (except the CGM Advisor Targeted Equity Fund series), Natixis Funds Trust II, Natixis Funds Trust III, Natixis Funds Trust IV, Harris Associates Investment Trust, Loomis Sayles Funds I, Loomis Sayles Funds II and Gateway Trust. The advisers and subadvisers to these mutual funds currently include Natixis Advisors, Reich & Tang, Loomis Sayles, AEW Management and Advisors, L.P., AlphaSimplex Group, LLC, BlackRock Investment Management, LLC (“BlackRock”), Dreman Value Management, LLC (“Dreman”), Gateway Investment Advisers, LLC, Hansberger Global Investors, Inc., Harris Associates L.P. and Vaughan Nelson Investment Management, L.P. Each of these advisers and subadvisers (except for BlackRock and Dreman) are subsidiaries of Natixis US and are thus “affiliated persons” under the 1940 Act by reason of being under common control by Natixis US. In addition, because the Funds, and other funds, are advised by firms that are affiliated with one another, they may be considered to be related companies comprising a “group of investment companies” under the 1940 Act. The Central Funds will participate in the credit facility only as lenders. Participation in such an interfund lending program would be voluntary for both borrowing and lending funds, and a Fund would participate in an interfund lending program only if the Board of Trustees determined that doing so would benefit a Fund. Should a Fund participate in such an interfund lending program, the Board of Trustees would establish procedures for the operation of the program by the advisers or an affiliate. The Funds may engage in the transactions described above without further notice to shareholders. The Funds may also make investments in related investment companies to the extent permitted by SEC regulations.

Loomis Sayles, located at One Financial Center, Boston, Massachusetts 02111, serves as the investment adviser to the Funds. Loomis Sayles is a subsidiary of Natixis US, which is part of Natixis Asset Management Group, an international asset management group based in Paris, France. Founded in 1926, Loomis Sayles is one of the oldest investment firms in the U.S. with over $ billion in assets under management as of December 31, 2008. Loomis Sayles is well known for its professional research staff, which is one of the largest in the industry. Loomis Sayles is responsible for making investment decisions for each Fund and for providing general business management and administration to each Fund.

The aggregate advisory fees paid by the Funds during the fiscal year ended September 30, 2008 as a percentage of each Fund’s average daily net assets were:

Mark F. Burns has served as portfolio manager of the Loomis Sayles Small Cap Growth Fund since January 2005. Mr. Burns, Vice President of Loomis Sayles, began his investment career in 1993 and joined Loomis Sayles in 1999. Mr. Burns holds the designation of Chartered Financial Analyst. He received a B.A. from Colby College and a M.B.A. from Cornell University and has over 14 years of investment experience.

Joseph R. Gatz has served as portfolio manager of the Loomis Sayles Small Cap Value Fund since January 2000. Mr. Gatz, Vice President of Loomis Sayles, began his investment career in 1985 and joined Loomis Sayles in 1999. Mr. Gatz holds the designation of Chartered Financial Analyst. He received a B.A. from Michigan State University and an M.B.A. from Indiana University and has over 22 years of investment experience.

John J. Slavik has served as portfolio manager of the Loomis Sayles Small Cap Growth Fund since April 2005. Mr. Slavik, Vice President of Loomis Sayles, began his investment career in 1991 and joined Loomis Sayles in April 2005. Prior to joining Loomis Sayles, Mr. Slavik was a vice president and portfolio manager at Westfield Capital Management, LLC from November 2000 to March 2005. Mr. Slavik holds the designation of Chartered Financial Analyst. He received a B.A. from the University of Connecticut and has over 16 years of investment experience.

Daniel G. Thelen has served as portfolio manager of the Loomis Sayles Small Cap Value Fund since April 2000. Mr. Thelen, Vice President of Loomis Sayles, began his investment career in 1990 and joined Loomis Sayles in 1996. Mr. Thelen holds the designation of Chartered Financial Analyst. He received a B.A. and an M.B.A. from Michigan State University and has over 17 years of investment experience.

Please see the SAI or information on Portfolio Manager compensation, other accounts under management by the Portfolio Managers and the Portfolio Managers’ ownership of securities in the Funds.

Admin Class shares of Loomis Sayles Small Cap Value Fund are offered exclusively through intermediaries, who will be the record owners of the shares. Admin Class shares may pay an administrative services fee at an annual rate of up to 0.25% of the average daily net assets attributable to Admin Class shares to securities dealers or financial intermediaries for providing personal service and account maintenance for their customers who hold these shares.

The payments described in this section, which may be significant to the dealers and the financial intermediaries, may create an incentive for a dealer or financial intermediary or their representatives to recommend or sell shares of a particular fund or share class over other mutual funds or share classes. Additionally, these payments may result in the Funds’ receiving certain marketing or servicing advantages that are not generally available to mutual funds that do not make such payments, including placement on a sales list, including a preferred or select sales list, or in other sales programs. These payments may create potential conflicts of interest between an investor and a dealer or other financial intermediary who is recommending a particular mutual fund over other mutual funds. Before investing, you should consult with your financial representative and review carefully any disclosure by the dealer or other financial intermediary as to what monies it receives from mutual fund advisers and distributors, as well as how your financial representative is compensated. Please see the SAI for additional information about payments made by the Distributor and its affiliates to dealers and other financial intermediaries. Please also contact your dealer or financial intermediary for details about payments it may receive.

Net asset value (“NAV”) is the price of one share of a Fund without a sales charge and is calculated each business day using this formula:

The net asset value of Fund shares is determined pursuant to policies and procedures approved by the Fund’s Board of Trustees as summarized below:

Equity securities. Last sale price on the exchange or market where primarily traded or if there is no reported sale during the day, the closing bid price.

Debt securities (other than short-term obligations). Based upon pricing service valuations, which determine valuations for normal, institutional-size trading units of such securities using market information, transactions for comparable securities and various relationships between securities which are generally recognized by institutional traders.

Short-term obligations (purchased with an original or remaining maturity of 60 days or less). Amortized cost (which approximates market value).

Securities traded on foreign exchanges. Market price on the non-U.S. exchange, unless a Fund believes that an occurrence after the close of that exchange will materially affect the security’s value. In that case, the security may be fair valued at the time the Fund determines its net asset value by or pursuant to procedures approved by the Board of Trustees. When fair valuing securities, the Funds may, among other things, use modeling tools or other processes that may take into account factors such as securities market activity and/or significant events that occur after the close of the local market and before the time a Fund’s net asset value is calculated.

Options. The Funds generally value exchange-traded options at the average of the closing bid and asked quotations.

Credit default swaps. Market value based on prices supplied by a pricing service, if available, or quotations obtained from broker dealers.

Foreign Currency Forward Contracts. Interpolated prices from information provided by an independent pricing service.

All other securities. Fair market value as determined by the adviser of the Fund pursuant to procedures approved by the Board of Trustees.

The Loomis Sayles Small Cap Value Fund was closed to new investors effective September 15, 2008. The Fund remains open to existing shareholders, including currently funded defined contribution, defined benefit and all other employee benefit plans and their participants. The Fund may not be added to any employee benefit platforms. Qualified plans may be permitted to invest in the Fund if they were approved by Loomis Sayles prior to September 15, 2008 and funded by September 30, 2008.

Independent investment advisers, as well as registered representatives using broker/dealers for existing accounts in the Loomis Sayles Small Cap Value Fund, are allowed to add assets for their existing client accounts. Clients of independent investment advisers and registered representatives who did not have an existing account in the Fund prior to September 15, 2008 are not permitted to open new accounts.

Directly from the Fund. Loomis Sayles Funds must receive your purchase request in proper form before the close of regular trading on the NYSE in order for you to receive that day’s NAV.

By wire. You also may wire subsequent investments by using the following wire instructions. Your bank may charge a fee for transmitting funds by wire.

By internet. If you have established a Personal Identification Number (PIN) and you have established the electronic transfer privilege, you can make subsequent investments through your online account at www.loomissayles.com. If you have not established a PIN but you have established the electronic transfer privilege from www.loomissayles.com, click on “Account Access” then click on the appropriate user type and then follow the instructions.

Each Fund is required by federal regulations to obtain personal information from you and to use that information to verify your identity. A Fund may not be able to open your account if the requested information is not provided. Each Fund reserves the right to refuse to open an account, close an account and redeem your shares at the then current price or take other such steps that the Fund deems necessary to comply with federal regulations if your identity is not verified.

The following table shows the investment minimum for each class of shares of each Fund.

Each Fund’s shares (except Admin Class shares) may be purchased by all types of tax-deferred retirement plans. If you wish to open an individual retirement account (“IRA”) with a Fund, you may obtain retirement plan forms available online at www.loomissayles.com, or by calling Loomis Sayles Funds at 800-633-3330. Admin Class shares are intended primarily for qualified retirement plans held in an omnibus fashion and are not available for purchase by individual investors.

Small Account Policy. In order to address the relatively higher costs of servicing smaller fund positions, each Fund may assess, on an annual basis, a minimum balance fee of $20 on accounts that fall below $500. The minimum balance fee is assessed by the automatic redemption of shares in the account in an amount sufficient to pay the fee. The minimum balance fee does not apply to directly registered accounts that (i) make monthly purchases through systematic investing or (ii) are retirement accounts. If your Fund account falls below $50 the Fund may redeem your remaining shares and send the proceeds to you. Accounts associated with defined contribution plans are excepted from the minimum balance fee and liquidation.

Because large redemptions are likely to require liquidation by the Fund of portfolio holdings, payment for large redemptions may be delayed for up to seven days to provide for orderly liquidation of such holdings. Under unusual circumstances, the Funds may suspend redemptions or postpone payment for more than seven days. Although most redemptions are made in cash, as described in the SAI, each Fund reserves the right to redeem shares in kind. If a shareholder receives a distribution in kind, the shareholder will bear the market risk associated with the distributed securities and would incur brokerage or other charges in converting the securities to cash.

If you have certificates for the shares you want to sell, you must include them along with completed stock power forms.

Retirement shares may not be redeemed by telephone. Please call Loomis Sayles Funds at 800-633-3330 for an IRA Distribution Form, or download the form online at www.loomissayles.com.

The telephone redemption privilege may be modified or terminated by the Funds without notice. Certain of the telephone redemption procedures may be waived for holders of Institutional Class shares.

By ACH. For ACH redemptions, proceeds (less any applicable redemption fee) will generally arrive at your bank within three business days.

You may exchange Retail Class shares of your Fund offered through this prospectus, subject to investment minimums, for Retail Class shares of any Loomis Sayles Fund that offers Retail Class shares without paying a sales charge, if any, or for Class A shares of Natixis Cash Management Trust, a money market fund that is advised by Natixis Advisors, an affiliate of Loomis Sayles. You may exchange Admin Class shares of your Fund offered through this prospectus, subject to investment minimums, for Admin Class shares of any Loomis Sayles Fund that offers Admin Class shares without paying a sales charge or for Class A shares of Natixis Cash Management Trust. You may exchange Institutional Class shares of your Fund, subject to investment minimums, for Institutional Class shares of any Loomis Sayles Fund that offers Institutional Class shares, for Class Y shares of any Natixis Fund that offers Class Y shares or for Class A shares of Natixis Cash Management Trust. All exchanges are subject to any restrictions described in the applicable Funds’ prospectuses.

You may be unable to hold your shares through the same financial intermediary if you engage in certain share exchanges. You should contact your financial intermediary for further details.

The value of Fund shares that you wish to exchange must meet the investment minimum requirements of the new fund.

Please remember that an exchange may be a taxable event for federal and/or state income tax purposes, so that you may realize a gain or loss that is subject to income tax.

A 2% redemption fee may apply to exchanges of shares within 60 days of their acquisition. See the section “Restrictions on Buying, Selling and Exchanging Shares.”

In order to convert shares, you must complete the Cross Share Exchange Form and return it to Loomis Sayles Funds at the following address:

intermediary’s restrictions on frequent trading in place of the Fund’s own restrictions if the Fund determines, in its discretion, that the financial intermediary’s restrictions provide reasonable protection for the Fund from excessive short-term trading activity. Please contact your financial representative for additional information regarding their policies for limiting the frequent trading of Fund shares.

short-term trading activity. If a Fund believes that a shareholder has engaged in market timing or other excessive, short-term trading activity in violation of the Fund’s policies through an omnibus account, the Fund will attempt to limit transactions by the underlying shareholder which engaged in such trading, although it may be unable to do so. The Fund may also limit or prohibit additional purchases of Fund shares by an intermediary. Investors should not assume the Funds will be able to detect or prevent all market timing or other trading practices that may disadvantage the Funds.

Redemption Fees. Shareholders will be charged a 2% redemption fee if they redeem, including redeeming by exchange, any class shares of these Funds within 60 days of their acquisition (including acquisition by exchange). The redemption fee is intended to help deter harmful short-term trading and to offset the costs to the Funds of short-term trading, such as portfolio transaction and market impact costs associated with redemption activity and administrative costs associated with processing redemptions. The redemption fee is deducted from the shareholder’s redemption or exchange proceeds and is paid to the Fund, although there may be a delay between the time the fee is deducted from such proceeds and when it is paid to the Fund.

The “first-in, first-out” (FIFO) method is used to determine the holding period of redeemed or exchange shares, which means that if you acquired shares on different days, the shares acquired first will be redeemed or exchanged first for purposes of determining whether the redemption fee applies. A new holding period begins with each purchase or exchange.

The redemption fee also does not apply to changes of account registration or transfers within the same Fund or to shares converted from one share class to another share class of the same Fund. In these transactions, subject to systematic limitations, the redemption fee aging period will carry over to the acquired shares, such that if the acquired shares are redeemed or exchanged before the expiration of the aging period, a redemption fee will be applied.

The Funds may modify or eliminate these waivers at any time. In addition, the Funds may modify the way the redemption fee is applied, including the amount of the redemption fee and/or the length of time shares must be held before the redemption fee is no longer applied, for certain categories of investors or for shareholders investing through financial intermediaries which apply the redemption fee in a manner different from that described above.

The ability of a Fund to assess a redemption fee on transactions by underlying shareholders who own their shares through omnibus or other accounts maintained by financial intermediaries may be limited. The Funds generally do not apply redemption fees at the omnibus account level. Instead, the Funds look to financial intermediaries to assess redemption fees on underlying shareholder accounts and remit these fees to the Funds. There are no assurances that a Fund will successfully identify all financial intermediaries or that financial intermediaries will properly assess redemption fees.

It is the policy of each Fund to pay its shareholders each year, as dividends, substantially all of its net investment income. Each Fund generally declares and pays such dividends annually. Each Fund expects to distribute substantially all net realized long- and short-term capital gains annually, after applying any available capital loss carryovers. To the extent permitted by law, the Board of Trustees may adopt a different schedule as long as payments are made at least annually.

Any capital gain distributions normally are made annually, but may be made more frequently as deemed advisable by the Funds and as permitted by applicable law. The trustees may change the frequency with which each Fund declares or pays dividends.

If you do not select an option when you open your account, all distributions will be reinvested.

Except where noted, the discussion below addresses only the U.S. federal income tax consequences of an investment in a Fund and does not address any non-U.S., state, or local tax consequences.

Taxation of Fund Distributions. For federal income tax purposes, distributions of investment income are generally taxable as ordinary income. Taxes on distributions of capital gains are determined by how long a Fund owned the investments that generated them, rather than how long a shareholder has owned his or her shares. Distributions attributable to the excess of net long-term capital gains from the sale of investments a Fund owned for more than one year over net short-term capital losses and that are designated by a Fund as capital gain dividends (“Capital Gain Dividends”) will generally be taxable to a shareholder receiving such distributions as long-term capital gain. Distributions attributable to the excess of net short-term capital gains from the sale of investments that a Fund owned for one year or less over, net long-term capital losses will be taxable as ordinary income.

For taxable years beginning before January 1, 2011, distributions of investment income designated by a Fund as derived from “qualified dividend income” will be taxed in the hands of individuals at the rates applicable to long-term capital gain, provided holding period and other requirements are met at both the shareholder and Fund levels. Income generated by investments in fixed income securities, REITs and derivatives is generally not eligible for treatment as qualified dividend income.

Distributions by a Fund to retirement plans and other investors that qualify for tax-exempt treatment under federal income tax laws will generally not be taxable. Special tax rules apply to investments through such retirement plans. If your investment is through such a plan, you should consult your tax adviser to determine the suitability of the Funds as an investment through your plan and the tax treatment of distributions to you (including distributions of amounts attributable to an investment in a Fund) from such a plan.

Corporations may be able to take a dividends-received deduction for a portion of income dividends they receive.

Redemption, Sale or Exchange of Fund Shares. A redemption, sale or exchange of Fund shares (including an exchange of Fund shares for shares of another Natixis or Loomis Sayles Fund) is a taxable event and will generally result in recognition of gain or loss. Gain or loss, if any, recognized by a shareholder on a redemption, sale, exchange or other disposition of Fund shares will generally be treated as long-term capital gain or loss if the shareholders held the shares for more than one year, and as shot-term gain or loss if the shareholder held the shares for one year or less, assuming in each case that the shareholder held the shares as capital assets. Short-term capital gains are generally taxed at the rates applicable to ordinary income. Any loss realized upon a disposition of shares held for six months or less will be treated as long-term, rather than short-term, capital loss to the extent of any Capital Gain Dividends received by the shareholder with respect to the shares. The deductibility of capital losses is subject to limitations.

Taxation of Certain Fund Investments. Each Fund’s investments in foreign securities may be subject to foreign withholding or other taxes. In that case, the Fund’s yield on those securities would be decreased. The Funds generally do not expect that shareholders will be entitled to claim a credit or deduction with respect to foreign taxes incurred by a Fund. In addition, a Fund’s investments in foreign securities or foreign currencies may be subject to special tax rules that have the effect of increasing or accelerating a Fund’s recognition of ordinary income and may affect the timing or amount of a Fund’s distributions.

A Fund’s investments in certain debt obligations, mortgage-backed securities, asset-backed securities, derivatives and REITs may cause a Fund to recognize taxable income in excess of the cash generated by such obligations. Thus, a Fund could be required to liquidate investments, including times when it may not be advantageous to do so, in order to satisfy its distribution requirements.

Non-U.S. Shareholders. Capital Gain Dividends generally will not be subject to withholding. Dividends, other than Capital Gain Dividends, paid to a shareholder that is not a “U.S. person” within the meaning of the Code (a “Foreign Person”) are subject to withholding of U.S. federal income tax at a rate of 30% (or lower applicable treaty rate). For further information, Foreign Persons should consult the SAI.

Backup Withholding. Each Fund is required in certain circumstances to apply backup withholding on taxable dividends, redemption proceeds and certain other payments that are paid to any shareholder (including a shareholder who is neither a citizen nor a resident of the U.S.) if the shareholder does not furnish the Funds certain information and certifications or the shareholder is otherwise subject to backup withholding. The backup withholding tax rate is 28% for amounts paid on or before December 31, 2010 and will be 31% for amounts paid after December 31, 2010. Backup withholding will not, however, be applied to payments that have been subject to the 30% withholding tax applicable to shareholders who are neither citizens nor residents of the United States.

Please see the SAI for additional information on the federal income tax consequences of an investment in the Funds.

You should consult your tax adviser for more information on your own tax situation, including possible federal, state, local, foreign or other applicable taxes.

If you would like more information about the Funds, the following documents are available free upon request:

Provides more detailed information about the Funds and their investment limitations and policies. The SAI has been filed with the SEC and is incorporated into this Prospectus by reference.

Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-202-551-8090.

A description of the Funds’ policies and procedures with respect to the disclosure of each Fund’s portfolio securities is available in the Funds’ SAI.

Loomis, Sayles & Company, L.P., which has been an investment adviser since 1926, is the investment adviser of the Funds.

Principal Investment Strategies The Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in fixed-income securities. In accordance with applicable Securities and Exchange Commission (“SEC”) requirements, the Fund will notify shareholders prior to any change to such policy taking effect. The Fund may invest up to 35% of its assets in lower-quality fixed-income securities (commonly known as “junk bonds”) and up to 20% of its assets in preferred stocks. Lower-quality fixed-income securities are below investment grade quality (i.e. none of the three major ratings agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Ratings Group) have rated the securities in one of their respective top four ratings categories) or, if the security is unrated, determined by Loomis Sayles to be of comparable quality. The Fund may invest in fixed-income securities of any maturity.

In deciding which securities to buy and sell, Loomis, Sayles & Company, L.P. (“Loomis Sayles”) will consider, among other things, the financial strength of the issuer, current interest rates, Loomis Sayles’ expectations regarding general trends in interest rates, and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return of those investments.

Three themes typically drive the Fund’s investment approach. First, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles Loomis Sayles believes are improving. Second, the Fund makes significant use of non-market related securities, which are securities that may not have a direct correlation with changes in interest rates. Loomis Sayles believes that the Fund may generate positive returns by having a portion of the Fund’s assets invested in non-market related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, Loomis Sayles analyzes different sectors of the economy and differences in the yields (“spreads”) of various fixed-income securities in an effort to find securities that Loomis Sayles believes may produce attractive returns for the Fund in comparison to their risk.

Loomis Sayles generally prefers securities that are protected against calls (early redemption by the issuer).

The Fund may invest any portion of its assets in securities of Canadian issuers and up to 20% of its assets in other foreign securities, including emerging market securities. The Fund may invest without limit in obligations of supranational entities (e.g., the World Bank).

The fixed-income securities in which the Fund may invest include corporate bonds and other debt securities, U.S. Government securities, commercial paper, zero-coupon securities, mortgage-backed securities, stripped mortgage-backed securities, collateralized mortgage obligations and other asset-backed securities, including mortgage dollar rolls, when-issued securities, real estate investment trusts (“REITs”), Rule 144A securities, repurchase agreements, and convertible securities. The Fund may engage in options and futures transactions, foreign currency transactions, swap transactions (including credit default swaps) and other derivative transactions. Loomis Sayles may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total return for Institutional Class shares for each of the last ten calendar years.¹

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]% ([ ]quarter [ ]) and the Fund’s worst quarter was down [ ]% ([ ] quarter [ ]).

to reflect return after taxes on distributions only and also returns after taxes on distributions and sale of Fund shares. The Barclays Capital U.S. Government/ Credit Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

Principal Investment Strategies The Fund will invest primarily in lower quality fixed-income securities (commonly known as “junk bonds”) and other securities that are expected to produce a relatively high level of income (including income producing preferred stocks and common stocks). Lower-quality fixed-income securities are below investment grade quality (i.e. none of the three major ratings agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Ratings Group) have rated the securities in one of their respective top four ratings categories) or, if the security is unrated, determined by Loomis Sayles to be of comparable quality. The Fund may invest in fixed-income securities of any maturity.

In deciding which securities to buy and sell, Loomis Sayles will consider, among other things, the financial strength of the issuer, current interest rates, Loomis Sayles’ expectations regarding general trends in interest rates and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return of those investments.

Three themes typically drive the Fund’s investment approach. First, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles Loomis Sayles believes are improving. Second, the Fund makes significant use of non-market related securities, which are securities that may not have a direct correlation with changes in interest rates. Loomis Sayles believes that the Fund may generate positive returns by having a portion of the Fund’s assets invested in non-market related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, Loomis Sayles analyzes different sectors of the economy and differences in the yields (“spreads”) of various fixed income securities in an effort to find securities that Loomis Sayles believes may produce attractive returns for the Fund in comparison to their risk.

Loomis Sayles generally prefers securities that are protected against calls (early redemption by the issuer).

The Fund may invest any portion of its assets in Canadian securities and up to 50% of its assets in other foreign securities, including emerging market securities. The Fund may invest without limit in obligations of supranational entities (e.g., the World Bank).

The fixed-income securities in which the Fund may invest include corporate bond and other debt securities, U.S. Government securities, commercial paper, zero-coupon securities, mortgage-backed securities, including mortgage dollar rolls, stripped mortgage-backed securities, collateralized mortgage obligations, asset-backed securities, when-issued securities, real estate investment trusts (“REITs”), Rule 144A securities, repurchase agreements, and convertible securities. The Fund may engage in options and futures transactions, foreign currency transactions, swap transactions (including credit default swaps) and other derivative transactions.

As a temporary defensive measure, the Fund may hold any portion of its assets in cash (U.S. Dollars, foreign currencies or multinational currency units) and/or invest in money market instruments and high quality debt securities as Loomis Sayles deems appropriate. The Fund may miss certain investment opportunities if it uses defensive strategies and thus may not achieve its investment objective.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total return for Institutional Class shares for each of the last ten calendar years.¹

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]% ([ ] quarter [ ]) and the Fund’s worst quarter was down [ ]% ([ ] quarter [ ]).

Performance Table The table below shows how the average annual total returns for Institutional Class shares of the Fund (before and after taxes) for the one-year, five-year, ten-year and since inception periods compare to those of the Barclays Capital High Yield Index (formerly known as “Lehman High Yield Index”), an unmanaged index that covers the universe of fixed rate, non-investment grade debt. You may not invest directly in an index. The Fund’s returns have also been calculated to reflect returns after taxes on distributions only and also returns after taxes on distributions and sale of Fund shares. The Barclays Capital High Yield Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

Investment Objective The Fund’s investment objective is above-average total return through a combination of current income and capital appreciation. The Fund’s investment objective may be changed without shareholder approval.

Principal Investment Strategies The Fund will invest at least 80% of its net assets (plus any borrowing made for investment purposes) in investment grade fixed-income securities. In accordance with applicable Securities and Exchange Commission (“SEC”) requirements, the Fund will notify shareholders prior to any change to such policy taking effect. It is anticipated that the Fund’s weighted average duration will generally be between two and five years.

The Fund will purchase only investment grade fixed-income securities. “Investment grade” are those securities that are rated as such at the time of purchase by at least one of the three major rating agencies (such as Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Rating Group) or, if unrated, are determined by Loomis Sayles to be of comparable quality. In the event that the credit rating of a security held by the Fund falls below investment grade (or, in the case of an unrated security, Loomis Sayles determines that the quality of such security has fallen below investment grade), the Fund will not be obligated to dispose of the security and may continue to hold the security if Loomis Sayles believes the investment is appropriate.

In deciding which securities to buy and sell, Loomis Sayles will consider, among other things, the financial strength of the issuer, current interest rates and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return of those investments.

Three themes typically drive the Fund’s investment approach. First, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles Loomis Sayles believes are improving. Second, the Fund makes significant use of non-market related securities, which are securities that may not have a direct correlation with changes in interest rates. Loomis Sayles believes that the Fund may generate positive returns by having a portion of the Fund’s assets invested in non-market related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, Loomis Sayles analyzes different sectors of the economy and differences in the yields (“spreads”) of various fixed income securities in an effort to find securities that Loomis Sayles believes may produce attractive returns for the Fund in comparison to their risk.

Loomis Sayles generally prefers securities that are protected against calls (early redemption by the issuer).

The Fund may invest any portion of its assets in securities of Canadian issuers and up to 20% of its assets in other foreign securities, including emerging markets securities. The Fund may invest without limit in obligations of supranational entities (e.g., the World Bank). The Fund may also invest in mortgage-related securities, including mortgage dollar rolls. The Fund may engage in futures transactions, swaps (including credit default swaps) and other derivative transactions.

The fixed-income securities in which the Fund may invest include corporate bond and other debt securities, U.S. Government securities, zero-coupon securities, mortgage-backed securities and other asset-backed securities, real estate investment trusts (“REITs”), Rule 144A securities and convertible securities.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each calendar year since its first full year of operations.

Performance Table The table below shows how the average annual total returns for Institutional Class shares of the Fund (before and after taxes) for the one-year, five-year, ten-year and since inception periods compare to those of the Barclays Capital U.S. Government/Credit Intermediate Index (formerly known as “Lehman U.S. Government/Credit Intermediate Index”), an unmanaged index that includes securities which have a remaining maturity of 1-10 years, including Treasuries and agencies, as well as other publicly issued investment grade corporate and non-corporate debentures that meet specified maturity, liquidity and quality requirements. You may not invest directly in an index. The Fund’s returns have also been calculated to reflect returns after taxes on distributions only and also returns after taxes on distributions and sale of Fund shares. The Barclays Capital U.S. Government/Credit Intermediate Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

Investment Objective The Fund’s investment objective is above-average total investment return through a combination of current income and capital appreciation. The Fund’s investment objective may be changed without shareholder approval.

Principal Investment Strategies The Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in investment grade fixed-income securities. In accordance with applicable Securities and Exchange Commission (the “SEC”) requirements, the Fund will notify shareholders prior to any change to such policy taking effect. The Fund may invest up to 10% of its assets in lower quality fixed-income securities (“junk bonds”) and up to 10% of its assets in preferred stocks. Lower-quality fixed-income securities are below investment grade quality (i.e. none of the three major ratings agencies (Moody’s Investors Service, Inc., Fitch Investor Services, Inc. or Standard and Poor’s Ratings Group) have rated the securities in one of their respective top four ratings categories) or, if the security is unrated, determined by Loomis Sayles to be of comparable quality. The Fund may invest in fixed income securities of any maturity.

In deciding which securities to buy and sell, the Fund will consider, among other things, the financial strength of the issuer, current interest rates, Loomis Sayles’ expectations regarding future changes in interest rates, and comparisons of the level of risk associated with particular investments with Loomis Sayles’ expectations concerning the potential return of those investments.

Three themes typically drive the Fund’s investment approach. First, Loomis Sayles generally seeks fixed-income securities of issuers whose credit profiles Loomis Sayles believes are improving. Second, the Fund makes significant use of non-market related securities, which are securities that may not have a direct correlation with changes in interest rates. Loomis Sayles believes that the Fund may generate positive returns by having a portion of the Fund’s assets invested in non-market related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, Loomis Sayles analyzes different sectors of the economy and differences in the yields (“spreads”) of various fixed income securities in an effort to find securities that Loomis Sayles believes may produce attractive returns for the Fund in comparison to their risk.

Loomis Sayles generally prefers securities that are protected against calls (early redemption by the issuer).

The Fund may invest any portion of its assets in securities of Canadian issuers and up to 20% of its assets in securities of other foreign issuers, including emerging markets securities. The Fund may invest without limit in obligations of supranational entities (e.g., the World Bank). The Fund may also invest in mortgage-related securities, including mortgage dollar rolls. The Fund may engage in futures transactions, swaps (including credit default swaps) and other derivative transactions.

The fixed-income securities in which the Fund may invest include corporate securities, U.S. Government securities, zero-coupon securities, mortgage-backed securities, collateralized mortgage obligations, when-issued securities, REITs, Rule 144A securities and structured notes.

Credit Risk is the risk that companies in which the Fund invests, or with which it does business, will fail financially or otherwise be unwilling or unable to meet their obligations to the Fund.

Currency Risk is the risk that the value of the Fund’s investments will fall as a result of changes in exchange rates.

Liquidity Risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects.

Management Risk is the risk that Loomis Sayles’ investment techniques will be unsuccessful and cause the Fund to incur losses.

Fund Performance The bar chart and table shown below give an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual returns for the one-year, five-year, ten-year and since inception periods compare to those of a broad measure of market performance. The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart The bar chart below shows the Fund’s total returns for Institutional Class shares for each of the last ten calendar years.¹

The Fund’s returns will vary. For example, during the period shown in the bar chart, the Fund’s best quarter was up [ ]% ([ ] quarter [ ]) and the Fund’s worst quarter was down [ ]% ([ ] quarter [ ]).

Performance Table The table below shows how the average annual total returns for Institutional Class shares of the Fund (before and after taxes) for the one-year, five-year, ten-year and since inception periods compare to those of the Barclays Capital U.S. Government/Credit Index (formerly known as “Lehman U.S. Government/Credit Index”), an unmanaged index which includes Treasuries and agencies as well as other publicly issued investment grade corporate and foreign debentures that meet specified maturity, liquidity and quality requirements. You may not invest directly in an index. The Fund’s returns have also been calculated to reflect return after taxes on distributions only and also return after taxes on distributions and sale of Fund shares. The Barclays Capital U.S. Government/ Credit Index returns have not been adjusted for ongoing management, distribution and operating expenses applicable to mutual fund shares.

The following table describes the fees and expenses that you may pay if you buy and hold shares of a Fund.

ANNUAL FUND OPERATING EXPENSES (expenses that are deducted from fund assets, as a percentage of daily net assets)

Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Each Fund may borrow money for temporary or emergency purposes in accordance with its investment restrictions.

This is the risk that the issuer or the guarantor of a fixed-income security, the issuer or guarantor of a security backing the asset-backed securities in which a Fund invests, or the counterparty to an over-the-counter transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. Each Fund may be subject to credit risk to the extent that it invests in fixed-income securities or is a party to over-the-counter transactions. A Fund that invests in lower rated fixed-income securities (commonly known as “junk bonds”) are subject to greater credit risk and market risk than funds that invest in higher quality fixed-income securities. Lower rated fixed-income securities are considered predominantly speculative with respect to the ability of the issuer to make timely principal and interest payments. Each Fund may be subject to credit risk to the extent that it invests in fixed-income securities or is a party to over-the-counter transactions.

A Fund that invests in certain of the U.S. Government securities, such as mortgage-backed securities that are issued by government sponsored enterprises, and securities issued by the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association and the Federal Home Loan Banks, are neither insured nor guaranteed by the U.S. Government. Such securities may be supported by the ability to borrow from the U.S. Treasury or only the credit of the issuing agency or instrumentality, and, as a result, may be subject to greater credit risk than securities issued by the U.S. Treasury.

A Fund that invests in fixed-income securities issued in connection with corporate restructurings by highly leveraged issuers or in fixed income securities that are not current in the payment of interest or principal (i.e., in default) will be subject to greater credit risk.

A Fund that invests in foreign securities is subject to increased credit risk, for example, because of the difficulties of requiring foreign entities to honor their contractual commitments and because a number of foreign governments and other issuers are already in default.

The securities markets of many foreign countries are relatively small, with a limited number of issuers and a small number of securities. In addition, foreign companies often are not subject to the same degree of regulation as U.S. companies. Reporting, accounting, and auditing standards of foreign countries differ, in some cases significantly, from U.S. standards. Among other things, nationalization, expropriation or confiscatory taxation, currency blockage, political changes, or diplomatic developments can cause the value of a Fund’s investments in a foreign country to decline. In the event of nationalization, expropriation, or other confiscation, a Fund could lose its entire foreign investment.

A Fund that invest in emerging markets may face greater foreign risk since emerging markets countries may be more likely to experience political and economic instability.

This is the risk that changes in interest rates will affect the value of a Fund’s investments in fixed-income securities, such as bonds, notes, asset-backed securities, and other income producing securities (such as preferred stock). Fixed-income securities are obligations of the issuer to make payments of principal and/or interest on future dates. Increases in interest rates may cause the value of a Fund’s investments to decline. Even Funds that generally invest a significant portion of their assets in high quality fixed-income securities are subject to interest rate risk. Interest rate risk is greater for funds that generally invest a significant portion of their assets in lower rated fixed-income securities (“junk bonds”) or comparable unrated securities.

Interest rate risk is compounded for Funds when they invest a significant portion of their assets in mortgage-related or asset-backed securities because the value of mortgage related and asset-backed securities generally is more sensitive to changes in interest rates than other types of fixed income securities. When interest rates rise, the maturities of mortgage-related and asset-backed securities tend to lengthen, and the value of these securities decreases more significantly than the value of other types of securities. In addition, these types of securities are subject to prepayment when interest rates fall, which generally results in lower returns because funds that hold these types of securities must reinvest assets previously invested in these types of securities in fixed income securities with lower interest rates.

Funds also face increased interest rate risk when they invest in fixed-income securities paying no current interest (such as zero-coupon securities and principal-only securities) interest-only securities and fixed-income securities paying non-cash interest in the form of other fixed-income securities because the prices of those types of securities tend to react more to changes in interest rates.

Certain funds may purchase securities of companies that are offered pursuant to an initial public offering (“IPO”). An IPO is a company’s first offering of stock to the public in the primary market, typically to raise additional capital. The Funds may purchase a “hot” IPO (also known as a “hot issue”), which is an IPO that is oversubscribed and, as a result, is an investment opportunity of limited availability. As a consequence, the price at which these IPO shares open in the secondary market may be significantly higher than the original IPO price. IPO securities tend to involve greater risk due, in part, to public perception and the lack of publicly available information and trading history. There is the possibility of losses resulting from the difference between the issue price and potential diminished value of the stock once traded in the secondary market. A Fund’s investment in IPO securities may have a significant impact on such Fund’s performance and may result in significant capital gains.

Liquidity risk exists when particular investments are difficult to purchase or sell, possibly preventing a Fund from selling these illiquid securities at the price or at the time desired. Liquidity issues could also make it difficult to value a Fund’s investments, which could also negatively impact net asset value. Derivatives and securities that involve substantial interest rate or credit risk tend to involve greater liquidity risk. In addition, liquidity risk tends to increase to the extent a Fund invests in securities whose sale may be restricted by law or by contract, such as Rule 144A securities.

The secondary markets in which lower-rated securities are traded may be less liquid than the market for higher grade securities. A lack of liquidity in the secondary trading markets could adversely affect the price at which the Fund could sell a particular lower-rated security when necessary to meet liquidity needs or in response to a specific economic event, such as a deterioration in the creditworthiness of the issuer, and could adversely affect and cause large fluctuations in the net asset value of a Fund’s shares. Adverse publicity and investor perceptions may decrease the values and liquidity of high yield securities generally.

This is the risk that the value of a Fund’s investments will change as financial markets fluctuate and that prices overall may decline. The value of a company’s securities may fall as a result of factors that directly relate to that company, such as decisions made by its management or lower demand for the company’s products or services. A security’s value also may fall because of factors affecting not just the issuer of a security, but companies in its industry or in a number of different industries, such as increases in production costs. The value of a Fund’s securities also may be affected by changes in financial market or other economic conditions, such as changes in interest rates or currency exchange rates. In addition, a company’s stock generally pays dividends only after the company makes required payments to holders of its bonds or other debt. For this reason, the value of the stock will usually react more strongly than bonds and other fixed income securities to actual or perceived changes in the company’s financial condition or prospects.

Market risk generally is greater for funds that invest substantially in small and medium-sized companies, since these companies tend to be more vulnerable to adverse developments than large companies. Furthermore, for funds that invest in fixed income securities, market risk tends to be greater when a Fund invests in fixed income securities with longer maturities.

Certain Funds may invest in mortgage-related securities, such as Government National Mortgage Association or Federal National Mortgage Association certificates, which differ from traditional debt securities. Among the major differences are that interest and principal payments are made more frequently, usually monthly, and that principal may be prepaid at any time because the underlying mortgage loans generally may be prepaid at any time. As a result, if a Fund purchases these assets at a premium, a faster-than-expected prepayment rate will tend to reduce yield to maturity, and a slower-than-expected prepayment rate may have the opposite effect of increasing yield to maturity. If a Fund purchases mortgage-related securities at a discount, faster-than-expected prepayments will tend to increase and slower-than-expected prepayments tend to reduce, yield to maturity. Prepayments and resulting amounts available for reinvestment by the Fund, are likely to be greater during a period of declining interest rates and, as a result, are likely to be reinvested at lower interest rates. Accelerated prepayments on securities purchased at a premium may result in a loss of principal if the premium has not been fully amortized at the time of prepayment. Although these securities will decrease in value as a result of increases in interest rates generally, they are likely to appreciate less than other fixed-income securities when interest rates decline because of the risk of prepayments. In addition, an increase in interest rates would also increase the inherent volatility of the Fund by increasing the average life of the Fund’s portfolio securities.

A mortgage dollar roll involves the sale of a security by a Fund and its agreement to repurchase the instrument at a specified time and price, and may be considered a form of borrowing for some purposes. A Fund will designate assets determined to be liquid in an amount sufficient to meet its obligations under the transactions. A dollar roll involves potential risks of loss that are different from those related to the securities underlying the transactions. A Fund may be required to purchase securities at a higher price than may otherwise be available on the open market. Since the counterparty in the transaction is required to deliver a similar, but not identical, security to a Fund, the security that a Fund is required to buy under the dollar roll may be worth less than an identical security. There is no assurance that a Fund’s use of the cash that it receives from a dollar roll will provide a return that exceeds borrowing costs.

The Fund may choose to rely on a financial intermediary’s restrictions on frequent trading in place of the Fund’s own restrictions if the Fund determines, in its discretion, that the financial intermediary’s restrictions provide reasonable protection for the Fund from excessive short-term trading activity. REITs are also subject to the possibilities of failing to qualify for tax-free pass-through of income under the Internal Revenue Code of 1986, as amended (the “Code”), and failing to maintain their exemptions from registration under the 1940 Act.

REITs may have limited financial resources, may trade less frequently and in a limited volume, and may be subject to more abrupt or erratic price movements than more widely held securities.

attempt to exercise rights with respect to the underlying security, including possible disposition in the market. However, the Fund may be subject to various delays and risks of loss, including possible declines in the value of the underlying security, possible reduced levels of income, inability to enforce rights and expenses involved in attempted enforcement. Repurchase agreements maturing in more than seven days may be considered illiquid securities.

The Funds may invest in structured notes, which are derivative debt instruments with principal and/or interest payments linked to the value of a commodity, a foreign currency, an index of securities, an interest rate, or other financial indicators (“reference instruments”). The payments on a structured note may vary based on changes in one or more specified reference instruments, such as a floating interest rate compared to a fixed interest rate, the exchange rates between two currencies, one or more securities or a securities or commodities index. A structured note may be positively or negatively indexed. For example, its principal amount and/or interest rate may increase or decrease if the value of the reference instrument increases, depending upon the terms of the instrument. The change in the principal amount payable with respect to, or the interest rate of, a structured note may be a multiple of the percentage change (positive or negative) in the value of the underlying reference instrument or instruments. Structured notes can be used to increase a Fund’s exposure to changes in the value of assets or to hedge the risks of other investments that a Fund holds.

credit facility only as lenders. Participation in such an interfund lending program would be voluntary for both borrowing and lending funds, and a Fund would participate in an interfund lending program only if the Board of Trustees determined that doing so would benefit a Fund. Should a Fund participate in such an interfund lending program, the Board of Trustees would establish procedures for the operation of the program by the advisers or an affiliate. The Funds may engage in the transactions described above without further notice to shareholders. The Funds may also make investments in related investment companies to the extent permitted by SEC regulations.

Loomis Sayles, located at One Financial Center, Boston, Massachusetts 02111, serves as the investment adviser to the Funds. Loomis Sayles is a subsidiary of Natixis Global Asset Management, which is part of Natixis Asset Management Group, an international asset management group based in Paris, France. Founded in 1926, Loomis Sayles and is one of the oldest investment firms in the U.S. with over $_____ billion in assets under management as of December 31, 2008. Loomis Sayles is well known for its research staff, which is one of the largest in the industry. Loomis Sayles is responsible for making investment decisions for each Fund and for providing general business management and administration to the Funds.

The aggregate advisory fees paid by the Funds during the fiscal year ended September 30, 2008 as a percentage of each Fund’s average daily net assets were:

A discussion of the factors considered by the Funds’ Board of Trustees when approving the Funds’ investment advisory contracts is available in the Funds’ annual reports for the fiscal year ended September 30, 2008.

Neil A. Burke has served as a co-portfolio manager of the Loomis Sayles Intermediate Duration Fixed Income Fund since December 2005. Mr. Burke is a Vice President of Loomis Sayles. He began his investment career in 1991 and has been at Loomis Sayles since 1997. Mr. Burke received a B.A. from the Catholic University of America and an M.B.A. from Boston College, and has over 16 years of investment experience.

Matthew J. Eagan has served as an associate portfolio manager of the Loomis Sayles Investment Grade Fixed Income Fund since September 2006 and the Loomis Sayles Fixed Income Fund and the Loomis Sayles Institutional High

Income Fund since February 2007. Mr. Eagan, Vice President of Loomis Sayles, began his investment career in 1989 and joined Loomis Sayles in 1997. He received a B.A. from Northeastern University and an M.B.A. from Boston University. Mr. Eagan holds the designation of Chartered Financial Analyst and has over 19 years of investment experience.

Daniel J. Fuss has served as portfolio manager of the Loomis Sayles Fixed Income Fund, Loomis Sayles Institutional High Income Fund and Loomis Sayles Investment Grade Fixed Income Fund since the inception of each Fund. Mr. Fuss is Vice Chairman, Director and Managing Partner of Loomis Sayles. He began his investment career in 1958 and has been at Loomis Sayles since 1976. Mr. Fuss holds the designation of Chartered Financial Analyst. He received a B.S. and an M.B.A. from Marquette University and has over 50 years of investment experience.

Kathleen C. Gaffney has served as an associate portfolio manager of the Loomis Sayles Investment Grade Fixed Income Fund since September 2006 and the Loomis Sayles Fixed Income Fund and the Loomis Sayles Institutional High Income Fund since February 2007. Ms. Gaffney, Vice President of Loomis Sayles, began her investment career in 1984 and joined Loomis Sayles in 1984. She received a B.A. from the University of Massachusetts. Ms. Gaffney holds the designation of Chartered Financial Analyst and has over 24 years of investment experience.

Steven J. Kaseta has served as a co-portfolio manager of the Loomis Sayles Investment Grade Fixed Income Fund since February 2002. Mr. Kaseta is a Vice President of Loomis Sayles. He began his investment career in 1982 and has been at Loomis Sayles since 1994. Mr. Kaseta holds the designation of Chartered Financial Analyst. He received an A.B. from Harvard University and an M.B.A. from the Wharton School at the University of Pennsylvania, and has over 26 years of investment experience.

Richard Raczkowski has served as a co-portfolio manager of the Loomis Sayles Intermediate Duration Fixed Income Fund since December 2005. Mr. Raczkowski is a Vice President of Loomis Sayles. He began his investment career in 1985 and has been at Loomis Sayles since 2001. He received a B.A. from the University of Massachusetts and an M.B.A. from Northeastern University, and has over 23 years of investment experience.

Clifton V. Rowe has served as portfolio manager of the Loomis Sayles Intermediate Duration Fixed Income Fund since December 2005. Mr. Rowe is a Vice President of Loomis Sayles. He began his investment career in 1992 and has been at Loomis Sayles since 1992. Mr. Rowe holds the designation of Chartered

Financial Analyst. He received a B.B.A. from James Madison University and an M.B.A. from the University of Chicago, and has over 16 years of investment experience.

Elaine M. Stokes has served as an associate portfolio manager of the Loomis Sayles Investment Grade Fixed Income Fund since September 2006 and the Loomis Sayles Fixed Income Fund and the Loomis Sayles Institutional High Income Fund since February 2007. Ms. Stokes, Vice President of Loomis Sayles, began her investment career in 1987 and joined Loomis Sayles in 1988. She received a B.S. from St. Michael’s College and has over 21 years of investment experience.

Please see the Statement of Additional Information (“SAI”) or information on Portfolio Manager compensation, other accounts under management by the Portfolio Managers and the Portfolio Managers’ ownership of securities in the Funds.

Natixis Distributors, L.P. (the “Distributor”), on behalf of Loomis Sayles, may pay certain broker-dealers and financial intermediaries whose customers are existing shareholders of the Funds a continuing fee at an annual rate of up to 0.35% of the value of Fund shares held for these customers’ accounts, although this continuing fee is paid by the Distributor, on behalf of Loomis Sayles, out of its own assets and is not assessed against the Fund.