PIONEER ADVISORY: Pioneer Absolute Return Credit Fund Name Change

May 2013 PIONEER ADVISORY: Pioneer Absolute Return Credit Fund Name Change Effective June 17, 2013, the Fund s name will change to Pioneer Dynamic Credit Fund. It should be noted that the Fund s portfolio management team and investment approach will not change. For questions regarding this change: Shareholders: please contact your financial advisor or call 800-225-6292 Advisors: please call 800-622-9876 A Word about Risk All investments are subject to risk, including the possible loss of principal. The Fund has the ability to invest in a wide variety of debt securities. The Fund may invest in underlying funds (ETFs and unit investment trusts). In addition to the Fund s operating expenses, you will indirectly bear the operating expenses of investments in any underlying funds. The Fund and some of the underlying funds employ leverage, which increases the volatility of investment returns and subjects the Fund to magnified losses if an underlying fund s investments decline in value. The Fund and some of the underlying funds may use derivatives, such as options and futures, which can be illiquid, may disproportionately increase losses, and have a potentially large impact on Fund performance. The Fund may invest in inflation-linked securities. As inflationary expectations increase, inflation-linked securities may become more attractive, because they protect future interest payments against inflation. Conversely, as inflationary concerns decrease, inflation-linked securities will become less attractive and less valuable. The Fund may invest in credit default swaps, which may in some cases be illiquid, and they increase credit risk since the fund has exposure to both the issuer of the referenced obligation and the counterparty to the credit default swap. The Fund may invest in floating rate loans. The value of collateral, if any, securing a floating rate loan can decline or may be insufficient to meet the issuer s obligations or may be difficult to liquidate. The Fund may invest in event-linked bonds. The return of principal and the payment of interest on event-linked bonds are contingent on the non-occurrence of a pre-defined trigger event, such as a hurricane or an earthquake of a specific magnitude. The Fund may invest in commodities. The value of commodity-linked derivatives may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, factors affecting a particular industry or commodity, international economic, political and regulatory developments, supply and demand, and governmental regulatory policies. The Fund may invest in zero coupon bonds and payment in kind securities, which may be more speculative and fluctuate more in value than other fixed income securities. The accrual of income from these securities are payable as taxable annual dividends to shareholders. Investments in equity securities are subject to price fluctuation. Investments in fixed income securities involve interest rate, credit, inflation, and reinvestment risks. As interest rates rise, the value of fixed income securities falls. The Fund may invest in mortgage-backed securities, which during times of fluctuating interest rates may increase or decrease more than other fixed-income securities. Mortgage-Backed securities are also subject to pre-payments. Prepayment risk is the chance that mortgagebacked bonds will be paid off early if falling interest rates prompt homeowners to refinance their mortgages. High yield bonds possess greater price volatility, illiquidity, and possibility of default. There is no assurance that these and other strategies used by the Fund or underlying funds will be successful. Absolute return funds are not intended to outperform stocks and bonds during strong market rallies. These risks may increase share price volatility. Please see the prospectus for a more complete discussion of the Fund s risks. Before investing, consider the product s investment objectives, risks, charges and expenses. These risks may increase share price volatility. Contact your advisor or Pioneer Investments for a prospectus or summary prospectus containing this information. Read it carefully. Neither Pioneer, nor its representatives are legal or tax advisors. In addition, Pioneer does not provide advice or recommendations. The investments you choose should correspond to your financial needs, goals, and risk tolerance. For assistance in determining your financial situation, please consult an investment professional. Not FDIC insured May lose value No bank guarantee Securities offered through Pioneer Funds Distributor, Inc., 60 State Street, Boston, MA. 02109. Underwriter of Pioneer mutual funds, Member SIPC 2013 Pioneer Investments us.pioneerinvestments.com 26746-00-0513

Pioneer Absolute Return Credit Fund A highly disciplined approach to managing risk and mining opportunity in volatile markets RCRAX INVESTOR GUIDE

Pioneer Absolute Return Credit Fund For Investors Who: Are seeking income Desire a cushion for their fixed income portfolio against cyclical market ups and downs as well as more extreme, unanticipated market events Recognize the value of a professionally managed multi-sector approach to credit investing in increasingly volatile markets Inception Date: April 29, 2011 Investment Goal: High current income; capital appreciation Benchmark: BofA Merrill Lynch U.S. Dollar 3-Month LIBOR Index Share Class Ticker Symbol Cusip Gross Expense Ratio A RCRAX 72388E100 1.20% C RCRCX 72388E209 2.10% Y RCRYX 72388E308 0.85% Overview This diversified bond fund focuses largely on below-investment grade debt instruments using a disciplined, multi-layered hedging strategy. This strategy allows investors to allocate capital in potentially high-yielding fixed income markets, while cushioning their portfolio to protect against various types of downside risk. Staying the Course in Shifting Markets Traditionally, investors have chosen fixed income securities for their potential to generate income and cushion portfolio volatility through the benefits of diversification*. Within a fixed income allocation, U.S. Treasuries and other high quality credit securities have provided an additional layer of protection against the downside volatility of more aggressive fixed income sectors, including high yield bonds. *Diversification does not assure a profit or protect against loss in a declining market. However, the fixed income landscape has changed dramatically in the past decade, driven in large part by the 2008-2009 credit crisis. The significant volatility of that period left fixed income investors particularly those with lower quality assets, such as high yield bonds reluctant to assume the level of risk necessary to pursue their long-term goals. Moreover, with U.S. government debt at unprecedented levels and interest rates rising, many question whether lower risk sectors, such as U.S. Treasuries and mortgages, will achieve adequate returns or effective diversification for their fixed income allocations going forward. Pioneer believes these and other evolving market trends signal the need for a new approach to hedging risk within a fixed income portfolio. Investment grade bonds such as U.S. Treasuries and mortgages have historically offered lower volatility compared to stocks and higher yielding bonds, but have also offered lower returns. While investment grade securities proved effective diversifiers in 2008 (see chart below), a future increase in interest rates may have a negative effect on their price (as interest rates and bond prices generally move in opposition). Diversification Benefit of Investment Grade Bonds Could Decrease Asset Class Average Annual Returns 2006-2010 60% Source: Morningstar Direct. Data represents past performance, which is no guarantee of future results. Investment grade bonds represented by the Barclays Capital Aggregate Bond Index, a measure of the performance of U.S. investment grade bonds; high yield bonds by the BOA Merrill Lynch High Yield Master II Index; and stocks by the Standard and Poor s 500 Index, a measure of U.S. stock performance. Indices are unmanaged and their returns assume reinvestment of dividends and, unlike mutual fund returns, do not reflect any fees or expenses associated with a mutual fund. It is not possible to invest directly in an index. 35% 10% -15% -40% 2010 2009 Investment grade bonds 2008 High yield bonds 2007 Stocks 2006

Beyond Traditional Diversification Portfolio Management Team The portfolio management team for Pioneer Absolute Return Credit Fund brings a depth of experience and expertise in an all areas of the credit markets. To help fixed income investors pursue diversification and income generation in this evolving credit market environment, Pioneer Investments developed Pioneer Absolute Return Credit Fund. This multi-sector fixed income portfolio is designed to help investors: g Buffer the effects of volatility during extreme market conditions through a multi-layered risk management strategy, which incorporates broad diversification across multiple credit sectors and geographies as well as cost-effective hedges that aim to smooth the effects of volatility over time. g Use market volatility as a tool to take advantage of opportunities across credit markets. The Fund s structure allows portfolio management to invest anywhere in the credit markets, in almost any fixed income security. A Broad Universe of Investment Options Pioneer Absolute Return Credit Fund has the ability to invest in a wide range of traditional and alternative fixed income and equity-linked securities. The Fund s management team regularly assesses the market environment and allocates portfolio assets among sectors and asset classes they believe offer favorable outlooks and the best value relative to risk. Portfolio Allocation The Fund may allocate among the following types of assets many of them rated below-investment grade which offer higher yield potential for the extra risk they carry. The derivative investments are primarily used in hedging downside risk in the portfolio, a strategy described in more detail on the following pages. Michael Temple Portfolio Manager Director of Credit Research 20 Years Industry Experience 9 Years with Pioneer While many of these asset classes carry greater risk than traditional fixed income investments, the Fund s portfolio management team provides the benefit of professional insight and experience, backed by a disciplined research process, to help manage volatility. In an Effort to... The Fund Will Invest in... Provide core fixed income exposure through traditional, income-producing assets Traditional fixed income securities such as investment grade and high yield bonds Andrew Feltus, CFA Portfolio Manager 19 Years Industry Experience 17 Years with Pioneer Provide additional income and diversification potential Apply an alternative means of portfolio flexibility and cushion against volatility Riskier, higher yielding fixed income assets with lower correlations to typical core fixed income assets. These may include bank loans, catastrophe bonds (event-linked securities), convertible securities, emerging market bonds, preferred securities, stressed mortgage-backed and asset-backed securities Derivative investments such as spot and forward currencies, credit default swaps basket products, options and futures

A Multi-Layered Approach to Managing Risk Traditional strategies for managing risk in a fixed income portfolio have involved increasing the credit quality of the portfolio and/or moving a portion of assets to lower-risk, government based securities. Implementing these strategies requires portfolio management to make significant and sometimes costly allocation adjustments that can take several weeks or even months. Avoiding Big Ship Challenges Think about a large ocean liner. When the crew sees trouble ahead, they can t maneuver instantly without risking damage to the ship. Instead, they must make a series of incremental adjustments to avoid the problem ahead. The same holds true for a large mutual fund. For portfolio managers, adjusting allocations, selling out of unwanted positions and buying new ones cannot happen instantly. Liquidity constraints and market volatility often hamper and may even be detrimental to the portfolio. Pioneer Absolute Return Credit Fund is designed to combat these big ship challenges more quickly and effectively through the application of three layers of risk control, or hedges. Pioneer Absolute Return Credit Fund Hedge Strategy Overview 3 Emergency Hedge Activated following periods of extreme market stress or unanticipated volatility 2 2 Dynamic Hedge Actively adjusts to changes in spreads and market volatility 1 Underlying Portfolio Diversification The Fund may invest in a broad range of sectors, capital structures, investment instruments and securities with varied levels of credit quality and duration

With a highly Diversified Portfolio at the base of its sophisticated approach to managing risk, the Fund s management team maintains a diligent watch for changes in market conditions, economic headwinds and other global market events that may increase downside portfolio risk. Investment Vocabulary Yield Spread Refers to the difference in yield between two investment instruments. The greater the difference, the higher the spread. Derivative A financial instrument whose value depends on other, more basic, underlying variables. In other words, it derives its value from something else. Common examples include swaps, futures, forwards, and options. For example: A coffee futures contract derives its value from the price of coffee beans. S&P Futures A cashsettled (futures contract) on the value of a particular stock or financial index. The S&P 500 Index is one of the most widely traded index futures contracts in the U.S. It is one of the best indicators of overall short-term market direction. Treasury Futures A financial derivative (a futures contract) with Treasury securities as the underlying asset. Some types of risk appear gradually. Widening yield spreads, for example, which have historically been signals of continued market volatility, are key to the Fund s Dynamic Hedge. As spreads widen beyond their historical average of around 500-600 basis points, the Fund s managers sell S&P futures, a position that will gain in value when the market goes down, to offset any losses from poorly performing credit instruments. As management sees evidence of narrowing spreads and market improvement, the hedge may be removed. Other types of risk may occur suddenly and take investors by surprise (the tech bubble burst of 2000, or the recent credit crisis of 2008-2009, for example). These can trigger fear-induced decisions that prove costly later on, should investors first attempt to sell into a plummeting market and then step back too late, missing a rally. The Fund s Emergency Hedge is activated when the S&P 500 drops by 3% or more in a month. Fund management will respond by buying Treasury futures, which may offer an effective cushion against performance volatility as well as the ability to generate some income. In addition, Treasury futures are highly liquid, which helps the Fund buy and sell them quickly. Here is a theoretical look at how portfolio management of Pioneer Absolute Return Credit Fund might respond to trends and events over the course of a credit cycle. The Fund s Hedging Strategy Over a Hypothetical Credit Cycle Spreads not yet widening, but cycle is beginning to deteriorate. Cycle Bottoming Upgrading credit quality, reducing convertible exposure Dynamic hedge still dialed down; emergency hedge off Beginning to Recover Spreads widening materially Lowering portfolio quality (opportunities become plentiful) Increase convertible exposure Dynamic hedge ratio increased; prepare for emergency hedge, should market conditions warrant Peak Expansion: Cycle improving, spreads tightening materially Balance out portfolio quality (opportunities become more scarce) Reduce duration ahead of rising interest rates Dynamic hedge ratio dialed down Time + This illustration in hypothetical in nature and not intended to represent an actual scenario of Fund allocation.

Pioneer s Edge in Fixed Income Investing Why Choose Pioneer for Fixed Income? Pioneer Investments is recognized across the industry as a preeminent credit investor with a long record of managing risk for investors across a wide range of credit cycles. Pioneer s core U.S. fixed income team includes 24 portfolio managers, analysts and traders, averaging over 20 years of experience. Our extensive credit management expertise and rigorous approach to research underlie the strategies behind all of our actively managed bond funds. Our collaborative environment encourages team members to think outside the box in developing innovative products to address the changing needs and ongoing challenges of investors. Is Pioneer Absolute Return Credit Fund Right for You? Today s more tumultuous fixed income markets require an investment approach that seeks both to buffer the effects of volatility as well as harness the opportunities that it can produce. Pioneer Absolute Return Credit Fund is designed to accomplish these goals for investors as they seek to diversify their portfolios and generate income. Contact your financial advisor for more information about the Fund, or visit us.pioneerinvestments.com. Why Consider Pioneer Absolute Return Credit Fund? Credit-oriented to pursue opportunities across all credit market environments Risk management through an innovative, multilayered strategy Professional management and insight that removes the intricate work of managing credit exposure from the shoulders of investors

A Word About Risk: All investments are subject to risk, including the possible loss of principal. Pioneer Absolute Return Credit ( ARC ) Fund has the ability to invest in a wide variety of debt securities. The Fund may invest in underlying funds (ETFs and unit investment trusts). In addition to the Fund s operating expenses, you will indirectly bear the operating expenses of investments in any underlying funds. The Fund and some of the underlying funds employ leverage, which increases the volatility of investment returns and subjects the Fund to magnified losses if an underlying fund s investments decline in value. The Fund and some of the underlying funds may use derivatives, such as options and futures, which can be illiquid, may disproportionately increase losses, and have a potentially large impact on Fund performance. The Fund may invest in inflation-linked securities. As inflationary expectations increase, inflation-linked securities may become more attractive, because they protect future interest payments against inflation. Conversely, as inflationary concerns decrease, inflation-linked securities will become less attractive and less valuable. The Fund may invest in credit default swaps, which may in some cases be illiquid, and they increase credit risk since the fund has exposure to both the issuer of the referenced obligation and the counterparty to the credit default swap. The Fund may invest in floating rate loans. The value of collateral, if any, securing a floating rate loan can decline or may be insufficient to meet the issuer s obligations or may be difficult to liquidate. The Fund may invest in event-linked bonds. The return of principal and the payment of interest on event-linked bonds are contingent on the non-occurrence of a predefined trigger event, such as a hurricane or an earthquake of a specific magnitude. The Fund may invest in commodities. The value of commodity-linked derivatives may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, factors affecting a particular industry or commodity, international economic, political and regulatory developments, supply and demand, and governmental regulatory policies. The Fund may invest in zero coupon bonds and payment in kind securities, which may be more speculative and fluctuate more in value than other fixed income securities. The accrual of income from these securities are payable as taxable annual dividends to shareholders. Investments in equity securities are subject to price fluctuation. Investments in fixed income securities involve interest rate, credit, inflation, and reinvestment risks. As interest rates rise, the value of fixed income securities falls. The Fund may invest in mortgage-backed securities, which during times of fluctuating interest rates may increase or decrease more than other fixed income securities. Mortgage-Backed securities are also subject to pre-payments. Prepayment risk is the chance that mortgage-backed bonds will be paid off early if falling interest rates prompt homeowners to refinance their mortgages. High yield bonds possess greater price volatility, illiquidity, and possibility of default. There is no assurance that these and other strategies used by the Fund or underlying funds will be successful. These risks may increase share price volatility. Please see the prospectus for a more complete discussion of the Fund s risks. The BofA Merrill Lynch U.S. Dollar 3-Month LIBOR represents the London interbank offered rate (LIBOR) with a constant 3-month average maturity. LIBOR is a composite of the rates of interest at which banks borrow from one another in the London market, and it is a widely used benchmark for short-term interest rates. It is not possible to invest directly in an index. Before investing, consider the product s investment objectives, risks, charges and expenses. Contact your advisor or Pioneer Investments for a prospectus (or summary prospectus, if available) containing this information. Read it carefully. Neither Pioneer, nor its representatives are legal or tax advisors. In addition, Pioneer does not provide advice or recommendations. The investments you choose should correspond to your financial needs, goals, and risk tolerance. For assistance in determining your financial situation, please consult an investment professional. Securities offered through Pioneer Funds Distributor, Inc., 60 State Street, Boston, Massachusetts 02109 Underwriter of Pioneer mutual funds, Member SIPC 2011 Pioneer Investments pioneerinvestments.com 24540-00-0411