Eaton Vance Income Fund of Boston

Investment Objectives

The Fund’s investment objective is to provide a high level of current income. The Fund's secondary objectives are to seek growth of income and capital.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may quality for a reduced sales charge if you invest, or agree to invest over a 13-month period, at least $50,000 in Eaton Vance funds. More information about these and other discounts is available from your financial intermediary and in Sales Charges beginning on page 38 of this Prospectus and page 23 of the Fund’s Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees Eaton Vance Income Fund of Boston	Class A	Class B	Class C	Class I	Class R	Class R6
Maximum Sales Charge (Load) (as a percentage of offering price)	4.75%	none	none	none	none	none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption)	none	5.00%	1.00%	none	none	none

Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)*

Annual Fund Operating Expenses Eaton Vance Income Fund of Boston	Class A	Class B	Class C	Class I	Class R	Class R6
Management Fees	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%
Distribution and Service (12b-1) Fees	0.25%	1.00%	1.00%	none	0.50%	none
Other Expenses	0.16%	0.16%	0.16%	0.16%	0.16%	0.08%
Total Annual Fund Operating Expenses	1.00%	1.75%	1.75%	0.75%	1.25%	0.67%

* Expenses in the table above and the Example below reflect the expenses of the Fund and the Boston Income Portfolio (the “Portfolio”), the Fund’s master Portfolio.

Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example Eaton Vance Income Fund of Boston (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	572	778	1,001	1,641
Class B	678	951	1,149	1,864
Class C	278	551	949	2,062
Class I	77	240	417	930
Class R	127	397	686	1,511
Class R6	68	214	373	835

Expense Example, No Redemption Eaton Vance Income Fund of Boston (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	572	778	1,001	1,641
Class B	178	551	949	1,864
Class C	178	551	949	2,062
Class I	77	240	417	930
Class R	127	397	686	1,511
Class R6	68	214	373	835

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” the portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 56% of the average value of its portfolio.

Principal Investment Strategies

The Fund currently invests primarily in high yield, high risk corporate bonds (commonly referred to as “junk bonds”) which are rated lower than investment grade (i.e., bonds rated lower than Baa by Moody’s Investors Service, Inc. (“Moody’s”) or lower than BBB by Standard & Poor’s Ratings Services (“S&P”)) or are unrated and of comparable quality as determined by the investment adviser. Bonds rated BBB and Baa have speculative characteristics, while lower rated bonds are predominantly speculative.

The Fund may hold securities that are unrated or in the lowest rating categories (rated C by Moody’s or D by S&P). Bonds rated C by Moody’s are regarded as having extremely poor prospects of ever attaining any real investment standing. Bonds rated D by S&P are in payment default or a bankruptcy petition has been filed and debt service payments are jeopardized.

The Fund invests a substantial portion of its assets in bonds issued in connection with mergers, acquisitions and other highly leveraged transactions. The Fund may invest in a wide variety of other income-producing debt securities (including senior floating rate loans and secured and unsecured subordinated loans, second lien loans and bridge loans) (“bank loans”), as well as preferred stocks that pay dividends. The Fund may invest up to 10% of its net assets in municipal obligations, including shares of affiliated investment companies. Some debt securities acquired by the Fund do not pay current income or do not make regular interest payments, while others may pay interest in the form of additional debt securities. The Fund may invest in zero coupon bonds, deferred interest bonds and bonds or preferred stocks on which the interest is payable-in-kind. The Fund will generally hold well in excess of 100 securities, which may help reduce investment risk.

The Fund may invest up to 25% of total assets in foreign and emerging market securities, which are predominantly U.S. dollar denominated. With respect to non-dollar denominated securities, the Fund may hedge currency fluctuations by entering into forward foreign currency exchange contracts.

The Fund may engage in derivative transactions. Transactions in derivative instruments may include: the purchase or sale of futures contracts on securities, indices or other financial instruments or currencies; options on futures contracts; exchange-traded and over-the-counter options on securities, indices, currencies and other instruments; interest rate, credit default, inflation and total return swaps; forward rate contracts and credit linked notes as well as instruments that have a greater or lesser credit risk than the security underlying that instrument. The Fund may use interest rate swaps for risk management purposes and not as a speculative investment and would typically use interest rate swaps to shorten the average interest rate re-set time of its holdings.

The Fund’s investments are actively managed and securities may be bought and sold on a daily basis. Preservation of capital is considered when consistent with the Fund’s objective. The investment adviser’s staff monitors the credit quality of securities held by the Fund and other securities available to the Fund. Although the investment adviser considers security ratings when making investment decisions, it performs its own credit and investment analysis utilizing various methodologies including “bottom up/top down” analysis and consideration of macroeconomic and technical factors, and does not rely primarily on the ratings assigned by the rating services. The portfolio managers attempt to improve yield and preserve and enhance principal value through timely trading. The portfolio managers also consider the relative value of securities in the marketplace in making investment decisions.

The Fund currently invests its assets in the Portfolio, a separate registered investment company with the same investment objectives and policies as the Fund.

Principal Risks

Risk of Lower Rated Investments. Investments rated below investment grade and comparable unrated securities (“junk bonds”) have speculative characteristics because of the credit risk associated with their issuers. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and illiquidity than higher rated investments.

Market Risk. Economic and other events (whether real or perceived) can reduce the demand for investments held by the Fund, which may reduce their market prices and cause the value of Fund shares to fall. The frequency and magnitude of such changes cannot be predicted. Certain securities and other investments held by the Fund can experience downturns in trading activity and, at such times, the supply of such instruments in the market may exceed the demand. At other times, the demand for such instruments may exceed the supply in the market. An imbalance in supply and demand in the market may result in valuation uncertainties and greater volatility, less liquidity, wider trading spreads and a lack of price transparency in the market. No active trading market may exist for certain investments, which may impair the ability of the Fund to sell or to realize the full value of such investments in the event of the need to liquidate such assets. Adverse market conditions may impair the liquidity of some actively traded investments. Fixed income markets have recently experienced a period of relatively high volatility. If the Federal Reserve continues to taper or reverse its quantitative easing stimulus program and/or increases interest rates, fixed income markets could experience continuing high volatility, which could negatively impact the Fund’s performance.

Interest Rate Risk. In general, the value of income securities will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Generally, securities with longer durations are more sensitive to changes in interest rates than shorter duration securities. In a rising interest rate environment, the duration of income securities that have the ability to be prepaid or called by the issuer may extend. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest rate.

Credit Risk. Investments in debt obligations are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Fund shares and income distributions. The value of a debt obligation also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of income securities and bank loans may be lowered if the financial condition of the party obligated to make payments with respect to such instruments changes. Credit ratings assigned by rating agencies are based on a number of factors and do not necessarily reflect the issuer’s current financial condition or the volatility or liquidity of the security. In the event of bankruptcy of the issuer of income securities and bank loans, the Fund could experience delays or limitations with respect to its ability to realize the benefits of any collateral securing the instrument. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Fund may be required to retain legal or similar counsel. This may increase the Fund’s operating expenses and adversely affect net asset value.

Risks of Zero-Coupon and Deep Discount Bonds and PIK Securities. Zero-coupon and deep discount bonds may experience greater volatility in market value due to changes in interest rates. The Fund accrues income on the discount amortization of these investments, which it is required to distribute each year. The Fund may be required to sell investments to obtain cash needed for income distributions. Securities purchased on a when-issued or forward commitment basis are subject to the risk that when delivered they will be worth less than the agreed upon payment price. Bonds and preferred stocks that make “in-kind” payments and other securities that do not pay regular income distributions may experience greater volatility in response to interest rate changes and issuer developments.

Derivatives Risk. The use of derivatives can lead to losses because of adverse movements in the price or value of the asset, index, rate or instrument underlying a derivative, due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create economic leverage in the Fund, which magnifies the Fund’s exposure to the underlying investment. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. When derivatives are used to gain or limit exposure to a particular market or market segment, their performance may not correlate as expected to the performance of such market, thereby causing the Fund to fail to achieve its original purpose for using such derivatives. A decision as to whether, when and how to use derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment.

Risk of Leveraged Transactions. Certain Fund transactions may give rise to leverage. Such transactions may include, among others, certain derivative transactions. The Fund is required to segregate liquid assets or otherwise cover the Fund’s obligation created by a transaction that may give rise to leverage. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. Leverage may cause the Fund’s share price to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Fund’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment.

Municipal Bond Risk. The amount of public information available about municipal bonds is generally less than for corporate equities or bonds, meaning that the investment performance of municipal bond investments may be more dependent on the analytical abilities of the investment adviser than stock or corporate bond investments. The secondary market for municipal bonds also tends to be less well-developed and less liquid than many other securities markets, which may limit an owner’s ability to sell its municipal bonds at attractive prices. The spread between the price at which an obligation can be purchased and the price at which it can be sold may widen during periods of market distress. Less liquid obligations can become more difficult to value and be subject to erratic price movements. The increased presence of non-traditional participants or the absence of traditional participants in the municipal markets may lead to greater volatility in the markets.

Foreign and Emerging Market Investment Risk. Because the Fund can invest a portion of its assets in foreign instruments, the value of Fund shares can be adversely affected by changes in currency exchange rates and political, economic and market developments abroad. In emerging or less developed countries, these risks can be more significant. Investment markets in emerging market countries are typically substantially smaller, less liquid and more volatile than the major markets in developed countries. As a result, Fund share values may be more volatile than if the Fund invested only in developed markets. Emerging market countries may have relatively unstable governments and economies. Emerging market investments often are subject to speculative trading, which typically contributes to volatility. Trading in foreign and emerging markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. The value of investments denominated in foreign currencies can be adversely affected by changes in foreign currency exchange rates.

Risk of Senior Loans. Risks of investments in Senior Loans are similar to the risks of lower rated securities, although interest rate risk may be reduced because Senior Loan rates generally are adjusted for changes in short-term interest rates. Junior Loans are subject to the same general risks. Due to their lower place in the borrower’s capital structure and possible unsecured status, Junior Loans may involve a higher degree of overall risk than Senior Loans of the same borrower.

Risks Associated with Active Management. The Fund is an actively managed portfolio and its success depends upon the investment skills and analytical abilities of the investment adviser to develop and effectively implement strategies to achieve the Fund’s investment objectives. Subjective decisions made by the investment adviser may cause the Fund to incur losses or to miss profit opportunities on which it may otherwise have capitalized.

General Fund Investing Risks. The Fund is not a complete investment program and you may lose money by investing in the Fund. All investments carry a certain amount of risk and there is no guarantee that the Fund will be able to achieve its investment objectives. Annual Fund Operating Expenses expressed as a percentage of the Fund’s average daily net assets may change as Fund assets increase and decrease, and Annual Fund Operating Expenses may differ in the future. Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objectives. In addition, the redemption by one or more large shareholders or groups of shareholders of their holdings in the Fund could have an adverse impact on the remaining shareholders in the Fund. Investors in the Fund should have a long-term investment perspective and be able to tolerate potentially sharp declines in value. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, entity or person. Mutual funds, investment advisers, other market participants and many securities markets are subject to rules and regulations and the jurisdiction of one or more regulators. Changes to applicable rules and regulations could have an adverse effect on securities markets and market participants, as well as on the Fund’s ability to execute its investment strategy.

Performance

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and how the Fund’s average annual returns over time compare with those of two broad-based securities market indices. The returns in the bar chart are for Class A shares and do not reflect a sales charge. If the sales charge was reflected, the returns would be lower. Past performance (both before and after taxes) is no guarantee of future results. Updated Fund performance information can be obtained by visiting www.eatonvance.com .

For the ten years ended December 31, 2013, the highest quarterly total return for Class A was 22.94% for the quarter ended June 30, 2009, and the lowest quarterly return was –23.52% for the quarter ended December 31, 2008. For the 30 days ended October 31, 2013, the SEC yield for Class A shares was 4.33%, for Class B shares was 3.80 %, for Class C shares was 3.80%, for Class I shares was 4.79% and for Class R shares was 4.30%. For current yield information call 1-800-262-1122.

Average Annual Total Returns Eaton Vance Income Fund of Boston	1 Year	5 Years	10 Years
Class A	2.18%	16.90%	7.11%
Class A After Taxes on Distributions	(0.45%)	13.60%	4.12%
Class A After Taxes on Distributions and Sales	1.19%	12.12%	4.25%
Class B	1.33%	16.98%	6.84%
Class C	5.33%	17.19%	6.84%
Class I	7.37%	18.37%	7.92%
Class R	7.03%	17.77%	7.35%
Class R6	7.37%	18.37%	7.92%
BofA Merrill Lynch U.S. High Yield Index	7.42%	18.64%	8.45%
BofA Merrill Lynch U.S. High Yield Constrained Index	7.41%	18.69%	8.46%

These returns reflect the maximum sales charge for Class A (4.75%) and any applicable contingent deferred sales charge (“CDSC”) for Class B and Class C. The Class R performance shown above for the period prior to January 5, 2004 (commencement of operations), is the performance of Class A shares at net asset value without adjustment for any differences in the expenses of the two classes and the Class R6 performance shown above for the period prior to July 1, 2014 (commencement of operations) is the performance of Class I shares at net asset value without adjustment for any differences in the expenses of the two classes. If adjusted for such differences, returns would be different. BofA Merrill Lynch^® indices not for redistribution or other uses; provided “as is”, without warranties, and with no liability. Eaton Vance has prepared this report, BofAML does not endorse it, or guarantee, review, or endorse Eaton Vance’s products. Investors cannot invest directly in an Index.

After-tax returns are calculated using the highest historical individual federal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and the actual characterization of distributions, and may differ from those shown. After-tax returns are not relevant to shareholders who hold shares in tax-deferred accounts or to shares held by non-taxable entities. After-tax returns for other Classes of shares will vary from the after-tax returns presented for Class A shares. Return After Taxes on Distributions for a period may be the same as Return Before Taxes for that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and the Sale of Fund Shares for a period may be greater than or equal to Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.