Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	FEDERATED INCOME SECURITIES TRUST
Prospectus Date	rr_ProspectusDate	Nov. 30, 2016
Federated Real Return Bond Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Federated Real Return Bond Fund (the "Fund")
Objective [Heading]	rr_ObjectiveHeading	RISK/RETURN SUMMARY: INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund's investment objective is to provide current income and real total returns. The reference to "real" means a total return in excess of the rate of inflation as measured by year-to-year changes in the consumer price index.
Expense [Heading]	rr_ExpenseHeading	RISK/RETURN SUMMARY: FEES AND EXPENSES
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold Class A Shares (A), Class C Shares (C) or Institutional Shares (IS) of the Fund. You may qualify for certain sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in certain classes (e.g., A class) of Federated Funds. More information about these and other discounts is available from your financial professional and in the "What Do Shares Cost?" section of the Prospectus on page 16.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	December 1, 2017
Fee Waiver Or Reimbursement Over Assets Later Of Termination Or Next Effective Prospectus	fist_FeeWaiverOrReimbursementOverAssetsLaterOfTerminationOrNextEffectiveProspectus	up to but not including the later of (the "Termination Date"): (a) December 1, 2017; or (b) the date of the Fund's next effective Prospectus.
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its 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 13% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	13.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for certain sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in certain classes (e.g., A class) of Federated Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 100,000
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	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 for the time periods indicated and then redeem all of your Shares at the end of those periods. Expenses assuming no redemption are also shown. The Example also assumes that your investment has a 5% return each year and that operating expenses are as shown in the table above and remain the same. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	RISK/RETURN SUMMARY: INVESTMENTS, RISKS and PERFORMANCE What are the Fund's Main Investment Strategies?
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund pursues its investment objective by investing primarily in investment-grade, inflation-indexed bonds issued by the U.S. government, its agencies or instrumentalities and corporations. Inflation-indexed bonds are fixed-income securities that are structured to provide protection against inflation. The Fund may invest in derivative instruments, such as credit default swap agreements, to synthesize inflation-indexed bonds. In addition, the Fund may invest in high-yield, foreign and non-U.S. dollar inflation-indexed fixed-income securities when the Adviser considers the risk-return prospects of those sectors to be attractive. There is no limitation on the maturity or remaining maturity of the fixed-income securities purchased by the Fund. The Adviser actively manages the Fund's portfolio seeking to outperform the Fund's benchmark, the  Bloomberg Barclays U.S. (TIPS) Index (formerly, Barclays U.S. (TIPS) Index). The Adviser seeks to enhance the Fund's performance by allocating relatively more of its portfolio to the types of inflation-indexed bonds that the Adviser expects to offer the best balance between real total return and risk and thus offer the greatest potential for return. The Fund will invest its assets so that at least 80% of its net assets (plus any borrowings for investment purposes) are invested in fixed-income investments. The Fund will notify shareholders at least 60 days in advance of any change in its investment policy that would enable the Fund to invest, under normal circumstances, less than 80% of its net assets in fixed-income investments.
Risk [Heading]	rr_RiskHeading	What are the Main Risks of Investing in the Fund?
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	All mutual funds take investment risks. Therefore, it is possible to lose money by investing in the Fund. The primary factors that may reduce the Fund's returns include: Interest Rate Risk. Prices of fixed-income securities generally fall when interest rates rise. The longer the duration of a fixed-income security, the more susceptible it is to interest rate risk. Recent and potential future changes in monetary policy made by central banks and/or their governments are likely to affect the level of interest rates. Duration measures the price sensitivity of a fixed-income security to changes in interest rates. Interest rate risks on inflation-indexed bonds can be more difficult to model than other types of bonds. It is important to emphasize that the Fund operates within a duration range of 0% to 120% of its benchmark. Issuer Credit Risk . It is possible that interest or principal on securities will not be paid when due. Non-investment grade securities generally have a higher default risk than investment-grade securities. Such non-payment or default may reduce the value of the Fund's portfolio holdings, its share price and its performance. Counterparty Credit Risk . Credit risk includes the possibility that a party to a transaction involving the Fund will fail to meet its obligations. This could cause the Fund to lose the benefit of the transaction or prevent the Fund from selling or buying other securities to implement its investment strategy. Call Risk . The Fund's performance may be adversely affected by the possibility that an issuer of a security held by the Fund may redeem the security prior to maturity at a price below its current market value. Prepayment Risk. When homeowners prepay their mortgages in response to lower interest rates, the Fund will be required to reinvest the proceeds at the lower interest rates available. Also, when interest rates fall, the price of mortgage-backed securities may not rise to as great an extent as that of other fixed-income securities. Liquidity Risk. Trading opportunities are more limited for fixed-income securities that have not received any credit ratings, have received ratings below investment grade or are not widely held. Sector Risk. A substantial part of the Fund's portfolio may be comprised of securities issued or credit enhanced by companies in similar businesses, or with other similar characteristics. As a result, the Fund will be more susceptible to any economic, business, political or other developments which generally affect these issuers. Risk Associated with Noninvestment-Grade Securities. Securities rated below investment grade, also known as junk bonds, generally entail greater market, credit and liquidity risks than investment-grade securities. For example, their prices are more volatile, economic downturns and financial setbacks may affect their prices more negatively, and their trading market may be more limited. Risk Related to the Economy. The value of the Fund's portfolio may decline in tandem with a drop in the overall value of the markets in which the Fund invests and/or the stock market. Economic, political and financial conditions may, from time to time, cause the Fund to experience volatility, illiquidity, shareholder redemptions, or other potentially adverse effects. Among other investments, lower-grade bonds may be particularly sensitive to changes in the economy. Risk Associated with Complex "Collateralized Mortgage Obligations (CMOs)." CMOs with complex or highly variable prepayment terms, such as companion classes, IOs, POs, Inverse Floaters and residuals, generally entail greater market, prepayment and liquidity risks than other mortgage-backed securities. For example, their prices are more volatile and their trading market may be more limited. Currency Risk. Exchange rates for currencies fluctuate daily. Accordingly, the Fund may experience increased volatility with respect to the value of its Shares and its returns as a result of its exposure to foreign currencies through direct holding of such currencies or holding of non-U.S. dollar denominated securities. Risk of Foreign Investing. Because the Fund invests in securities issued by foreign companies, the Fund's share price may be more affected by foreign economic and political conditions, taxation policies and accounting and auditing standards than would otherwise be the case. Leverage Risk. Leverage risk is created when an investment, which includes, for example, an investment in a derivative contract, exposes the Fund to a level of risk that exceeds the amount invested. Changes in the value of such an investment magnify the Fund's risk of loss and potential for gain. Investments can have these same results if their returns are based on a multiple of a specified index, security or other benchmark. Risk of Investing in Inflation-Indexed Securities. As more fully described in this Prospectus, the value of inflation-indexed securities may decline when interest rates rise and inflation declines. Additionally, it is possible that the interest payments on inflation-indexed securities may be reduced to the point that there is not any net income to distribute. Risk of Investing in Derivative Contracts and Hybrid Instruments. Derivative contracts and hybrid instruments involve risks different from, or possibly greater than, risks associated with investing directly in securities and other traditional investments. Specific risk issues related to the use of such contracts and instruments include valuation and tax issues, increased potential for losses and/or costs to the Fund and a potential reduction in gains to the Fund. Each of these issues is described in greater detail in this prospectus. Derivative contracts and hybrid instruments may also involve other risks described in this prospectus or the Fund's Statement of Additional Information (SAI), such as interest rate, credit, currency, liquidity and leverage risks. Technology Risk. The Adviser uses various technologies in managing the Fund, consistent with its investment objective and strategy described in this Prospectus. For example, proprietary and third-party data and systems are utilized to support decision-making for the Fund. Data imprecision, software or other technology malfunctions, programming inaccuracies and similar circumstances may impair the performance of these systems, which may negatively affect Fund performance. The Shares offered by this Prospectus are not deposits or obligations of any bank, are not endorsed or guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.
Risk Lose Money [Text]	rr_RiskLoseMoney	All mutual funds take investment risks. Therefore, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	The Shares offered by this Prospectus are not deposits or obligations of any bank, are not endorsed or guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance: Bar Chart and Table Risk/Return Bar Chart
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and performance table below reflect historical performance data for the Fund and are intended to help you analyze the Fund's investment risks in light of its historical returns. The bar chart shows the variability of the Fund's IS class total returns on a calendar year-by-year basis. The Average Annual Total Return Table shows returns for each class averaged over the stated periods, and includes comparative performance information. The Fund's performance will fluctuate, and past performance (before and after taxes) is not necessarily an indication of future results. Updated performance information for the Fund is available under the "Products" section at FederatedInvestors.com or by calling 1-800-341-7400.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and performance table below reflect historical performance data for the Fund and are intended to help you analyze the Fund's investment risks in light of its historical returns. The bar chart shows the variability of the Fund's IS class total returns on a calendar year-by-year basis.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-341-7400
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	FederatedInvestors.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's performance will fluctuate, and past performance (before and after taxes) is not necessarily an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Federated Real Return Bond Fund - IS Class
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund's IS class total return for the nine-month period from January 1, 2016 to September 30, 2016, was 5.29%. Within the periods shown in the bar chart, the Fund's IS class highest quarterly return was 4.79% (quarter ended September 30, 2007). Its lowest quarterly return was (5.44)% (quarter ended June 30, 2013).
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Return Table
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using a standard set of assumptions. The stated returns assume the highest historical federal income and capital gains tax rates. These after-tax returns do not reflect the effect of any applicable state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	After-tax returns are not relevant to investors holding Shares through a 401(k) plan, an Individual Retirement Account or other tax-advantaged investment plans.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown only for the IS class, and after-tax returns for A and C classes will differ from those shown for the IS class.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	In addition to Return Before Taxes, Returns After Taxes is shown for the Fund's IS class to illustrate the effect of federal taxes on Fund returns. After-tax returns are shown only for the IS class, and after-tax returns for A and C classes will differ from those shown for the IS class. Actual after-tax returns depend on each investor's personal tax situation, and are likely to differ from those shown. After-tax returns are calculated using a standard set of assumptions. The stated returns assume the highest historical federal income and capital gains tax rates. These after-tax returns do not reflect the effect of any applicable state and local taxes. After-tax returns are not relevant to investors holding Shares through a 401(k) plan, an Individual Retirement Account or other tax-advantaged investment plans. (For the Period Ended December 31, 2015)
Federated Real Return Bond Fund | A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.50%
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price)	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee (as a percentage of amount redeemed, if applicable)	rr_RedemptionFeeOverRedemption	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fee	rr_ManagementFeesOverAssets	0.40%
Distribution (12b-1) Fee	rr_DistributionAndService12b1FeesOverAssets	none	[1]
Other Expenses	rr_OtherExpensesOverAssets	1.68%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.09%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(1.34%)	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.75%
1 Year	rr_ExpenseExampleYear01	$ 653
3 Years	rr_ExpenseExampleYear03	1,075
5 Years	rr_ExpenseExampleYear05	1,523
10 Years	rr_ExpenseExampleYear10	2,762
1 Year	rr_ExpenseExampleNoRedemptionYear01	653
3 Years	rr_ExpenseExampleNoRedemptionYear03	1,075
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,523
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,762
1 Year	rr_AverageAnnualReturnYear01	(6.53%)
5 Years	rr_AverageAnnualReturnYear05	(0.40%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.29%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 18, 2006
Federated Real Return Bond Fund | C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	1.00%
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price)	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee (as a percentage of amount redeemed, if applicable)	rr_RedemptionFeeOverRedemption	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fee	rr_ManagementFeesOverAssets	0.40%
Distribution (12b-1) Fee	rr_DistributionAndService12b1FeesOverAssets	0.75%
Other Expenses	rr_OtherExpensesOverAssets	1.68%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.84%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(1.34%)	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.50%
1 Year	rr_ExpenseExampleYear01	$ 387
3 Years	rr_ExpenseExampleYear03	880
5 Years	rr_ExpenseExampleYear05	1,499
10 Years	rr_ExpenseExampleYear10	3,166
1 Year	rr_ExpenseExampleNoRedemptionYear01	287
3 Years	rr_ExpenseExampleNoRedemptionYear03	880
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,499
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 3,166
1 Year	rr_AverageAnnualReturnYear01	(3.93%)
5 Years	rr_AverageAnnualReturnYear05	(0.25%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.12%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 18, 2006
Federated Real Return Bond Fund | IS
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends (and other Distributions) (as a percentage of offering price)	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee (as a percentage of amount redeemed, if applicable)	rr_RedemptionFeeOverRedemption	none
Exchange Fee	rr_ExchangeFeeOverRedemption	none
Management Fee	rr_ManagementFeesOverAssets	0.40%
Distribution (12b-1) Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	1.45%	[3]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.86%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(1.36%)	[2]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.50%
1 Year	rr_ExpenseExampleYear01	$ 189
3 Years	rr_ExpenseExampleYear03	585
5 Years	rr_ExpenseExampleYear05	1,006
10 Years	rr_ExpenseExampleYear10	2,180
1 Year	rr_ExpenseExampleNoRedemptionYear01	189
3 Years	rr_ExpenseExampleNoRedemptionYear03	585
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,006
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,180
2007	rr_AnnualReturn2007	11.39%
2008	rr_AnnualReturn2008	(0.90%)
2009	rr_AnnualReturn2009	11.37%
2010	rr_AnnualReturn2010	2.90%
2011	rr_AnnualReturn2011	5.28%
2012	rr_AnnualReturn2012	5.91%
2013	rr_AnnualReturn2013	(4.67%)
2014	rr_AnnualReturn2014	(0.31%)
2015	rr_AnnualReturn2015	(2.00%)
Year to Date Return, Label	rr_YearToDateReturnLabel	The Fund's IS class total return for the nine-month period
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2016
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	5.29%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest quarterly return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	4.79%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest quarterly return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2013
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(5.44%)
1 Year	rr_AverageAnnualReturnYear01	(2.00%)
5 Years	rr_AverageAnnualReturnYear05	0.76%
Since Inception	rr_AverageAnnualReturnSinceInception	3.02%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 18, 2006
Federated Real Return Bond Fund | Return After Taxes on Distributions | IS
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.31%)
5 Years	rr_AverageAnnualReturnYear05	(0.13%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.29%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 18, 2006
Federated Real Return Bond Fund | Return After Taxes on Distributions and Sale of Fund Shares | IS
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.13%)
5 Years	rr_AverageAnnualReturnYear05	0.25%
Since Inception	rr_AverageAnnualReturnSinceInception	2.28%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 18, 2006
Federated Real Return Bond Fund | Bloomberg Barclays U.S. TIPS Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.44%)	[4]
5 Years	rr_AverageAnnualReturnYear05	2.55%	[4]
Since Inception	rr_AverageAnnualReturnSinceInception	4.25%	[4]
Federated Real Return Bond Fund | Morningstar Inflation-Protected Bond Funds Average
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.36%)	[5]
5 Years	rr_AverageAnnualReturnYear05	1.55%	[5]
Since Inception	rr_AverageAnnualReturnSinceInception	3.18%	[5]

[1] The Fund has adopted a Distribution (12b-1) Plan for its Class A Shares pursuant to which the A class of the Fund may incur or charge a Distribution (12b-1) fee of up to a maximum amount of 0.05%. No such fee is currently incurred or charged by the A class of the Fund. The A class of the Fund will not incur or charge such a Distribution (12b-1) fee until such time as approved by the Fund's Board of Trustees (the "Trustees").

[2] The Adviser and certain of its affiliates on their own initiative have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (excluding Acquired Fund Fees and Expenses, interest expense, extraordinary expenses, line of credit expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund's A, C and IS classes (after the voluntary waivers and/or reimbursements) will not exceed 0.74%, 1.49% and 0.49% (the "Fee Limit"), respectively, up to but not including the later of (the "Termination Date"): (a) December 1, 2017; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Trustees.

[3] The Fund may incur or charge certain service fees (shareholder services/account administration fees) on its IS class of up to a maximum amount of 0.25%. No such fees are currently incurred or charged by the IS class of the Fund. The IS class of the Fund will not incur or charge such fees until such time as approved by the Trustees.

[4] The Bloomberg Barclays U.S. TIPS Index is a market value-weighted index that tracks inflation-protected securities issued by the U.S. Treasury. Effective August 24, 2016, the name changed from "Barclays U.S. TIPS Index" to "Bloomberg Barclays U.S. TIPS Index."

[5] Morningstar figures represent the average of the total returns reported by all the mutual funds designated by Morningstar as falling into the respective category indicated. They do not reflect sales charges.