Pioneer Investments Introduces New Closed-End Fund: Pioneer Diversified High Income Trust.

First U.S. Closed-End Fund To Offer Retail Investors Significant Exposure to "Cat Bonds"

BOSTON -- Pioneer Investments today announced the launch of Pioneer Diversified High Income Trust (Amex: HNW), the first U.S. closed-end fund to offer investors significant exposure to event-linked bonds, also known as catastrophe ("Cat") bonds. Cat bonds typically are issued by special purpose entities created by insurers to spread the risk of losses from low frequency natural catastrophes such as hurricanes and earthquakes. Cat bonds are a rapidly growing asset class with the potential to provide attractive returns. Pioneer Diversified High Income Trust invests in Cat bonds as part of a diversified portfolio that also includes floating rate bank loans and global high yield bonds. The fund's primary investment objective is to seek a high level of current income. As a secondary objective, the fund seeks capital appreciation.

The fund issued 7.3 million shares at an initial price of $25 per share, resulting in gross assets raised of $182.5 million (exclusive of the underwriters' overallotments) through an initial public offering managed by lead underwriter UBS Securities LLC. In addition to the common share offering, the fund expects to use financial leverage up to approximately 33% of gross assets. Based on the common shares issued, and assuming leverage at the anticipated levels, the fund's total assets would reach approximately $260 million. Shares in the fund began trading on the American Stock Exchange today under the symbol HNW.

"Pioneer Investments is an industry leader in high yield investing, and this fund is another example of our ability to provide investors with innovative approaches to this market," said Daniel K. Kingsbury, President and CEO of Pioneer Investment Management USA Inc. "We are giving investors exposure to a new asset class--Cat bonds--within a diversified portfolio," he added.

Kenneth Taubes, Director of U.S. Fixed Income at Pioneer Investments, said, "Our approach is to invest in a broadly diversified portfolio of high-yielding debt securities that are designed to help manage risk through investments in different asset classes that historically have had low correlations to each other and to most traditional asset classes. The goal is to achieve a higher yield than traditional high yield funds with lower volatility."

The portfolio's initial asset allocation will include approximately 37.5% in global high yield bonds, approximately 37.5% in floating rate loans, and approximately 25% in event-linked bonds. The fund limits its investment in event-linked bonds to no more than 35% of the fund's portfolio.

The fund is managed by members of Pioneer Investment's U.S.-based fixed-income team, along with Montpelier Capital Advisors, Ltd., which serves as subadviser with respect to the event-linked bond allocation. Montpelier Capital Advisors is a subsidiary of Montpelier Re Holdings Ltd, (NYSE: MRH) a Bermuda-based provider of global property and casualty reinsurance products. The subadviser is newly created and has had no prior operations, but its management team has substantial experience evaluating and monitoring event-linked instruments at its parent company, Montpelier Re. Montpelier Re's significant expertise in evaluating catastrophic- and insurance-related risks is ideally suited to the analysis and selection of event-linked bonds for the portfolio

The global high yield portion of the fund will be managed by Andrew Feltus, a 15-year industry veteran who has managed global high yield securities for Pioneer Investments since 2001. Feltus is currently Portfolio Manager of Pioneer Global High Yield Fund, Pioneer High Yield Fund, Pioneer High Income Trust, Pioneer Global High Yield VCT Portfolio, and additional institutional accounts.

The floating rate bank loan portion of the fund will be managed by Jonathan D. Sharkey, who has 13 years of experience in the bank loan sector, including loan origination, analysis, and portfolio management. Sharkey is a Portfolio Manager of Pioneer Floating Rate Trust and also is responsible for managing bank loan securities across a range of products. Prior to joining Pioneer Investments, Sharkey spent four years with Putman Investments where he was a Corporate Bond and Bank Loan Analyst, three years with Cypress Tree Investments where he was a Principal and Bank Loan Analyst and five years with BankBoston as Vice President, Relationship Manager.

The fund's overall asset-allocation decision-making process will be managed by Charles Melchreit, a Pioneer Investments Vice President and Portfolio Manager of Pioneer Government Income Fund and Pioneer Short Term Income Fund, and is a member of Pioneer Investment's Core Plus team. Melchreit joined Pioneer in 2006. From 2003 to 2004, he was a Managing Director at Cigna Investment Management. Prior to Cigna, he was a Senior Vice President and Portfolio Manager at Aeltus Investment Management.

About Pioneer Investments

Pioneer Investments is the trade name for Pioneer Global Asset Management S.p.A. and its subsidiaries, a global investment firm with offices in 22 countries and approximately $319 billion in assets under management as of April 30, 2007, of which approximately $83 billion was managed in the U.S. Founded in 1928, our flagship mutual fund, Pioneer Fund, is the third-oldest mutual fund in the U.S. Pioneer Investment Management, Inc. is the investment advisory subsidiary of Pioneer Investment Management USA Inc., which is the North American operating subsidiary of Pioneer Global Asset Management S.p.A., a wholly-owned subsidiary of UniCredito Italiano S.p.A.

About Montpelier Capital Advisors, Ltd.

Montpelier Capital Advisors, Ltd. is a subsidiary of Montpelier Re Holdings Ltd, (NYSE: MRH) a Bermuda-based provider of global property and casualty reinsurance products. Pioneer Investments has engaged Montpelier Capital Advisors, Ltd. to act as the fund's investment subadviser with respect to the Fund's investments in event-linked bonds. The subadviser also assists Pioneer Investments in the evaluation of the relative value of investments in event-linked bonds, compared to other sectors of the fixed income securities markets. When analyzing the fund's potential investments in event-linked bonds, the subadviser's management team intends to utilize the same tools and skills for evaluating event-linked bonds that it has been using in connection with underwriting insurance and reinsurance policies. Montpelier Re's significant expertise in evaluating catastrophic and insurance-linked risk is ideally suited to the analysis and selection of event-linked bonds for the portfolio.

Please consider the fund's investment objectives, risks, charges and expenses carefully before investing. The prospectus contains this and other information about the fund and should be read carefully before you invest or send money. To obtain a prospectus and for other information on Pioneer funds, contact your advisor or Pioneer at 800-225-6292 or visit our web site: www.pioneerinvestments.com.

The fund is not a complete investment program and should be considered only as an addition to an investor's existing diversified portfolio of investments. Due to uncertainty inherent in all investments, there can be no assurance that the fund will achieve its investment objectives. The fund is a newly organized, diversified, closed-end management investment company and has no operating history or history of public trading.

Risks

Subadviser Risk. The Subadviser a newly formed investment adviser registered with the Securities and Exchange Commission and has no prior history of acting as an investment adviser or subadviser to a registered investment company. Credit risk is the risk that an issuer of a security in which the Fund invests will become unable to meet its obligation to make interest and principal payments. The fund may invest all or a substantial portion of its assets in global high yield debt securities, floating rate loans, event-linked bonds and other debt securities that are rated below investment grade (commonly referred to as "junk bonds" or "high yield securities"), that is, rated Ba or below by Moody's or BB or below by S&P, or unrated securities determined by the Adviser or Subadviser to be of comparable credit quality. Investment in debt securities of below investment grade quality involves substantial risk of loss. "Junk bonds" are considered predominantly speculative with respect to the issuer's ability to pay interest and repay principal and are susceptible to default or decline in market value due to adverse economic and business developments.

Floating Rate Loan Risk. The risks associated with floating rate loans are similar to the risks of junk bonds, although floating rate loans are typically senior and secured in contrast to below investment grade debt securities, commonly referred to as "junk bonds," which are often subordinated and unsecured. The fund's investments in floating rate loans typically are rated below investment grade and are considered speculative because of the credit risk of their issuers. Moreover, any specific collateral used to secure a loan may decline in value or lose all its value or become illiquid, which would adversely affect the loan's value. Economic and other events, whether real or perceived, can reduce the demand for certain floating rate loans or floating rate loans generally, which may reduce market prices and cause the fund's net asset value per share to fall. The frequency and magnitude of such changes cannot be predicted. No active trading market may exist for many floating rate loans, and some floating rate loans may be subject to restrictions on resale. Any secondary market may be subject to irregular trading activity, wide bid/ask spreads and extended trade settlement periods, which may impair the ability of the fund to realize full value on the disposition of an illiquid floating rate loan and cause a material decline in the fund's net asset value.

Event-Linked Bond Risk. For some event-linked bonds, the trigger event or magnitude of losses may be based on company-wide losses, index- portfolio losses, industry indexes or readings of scientific instruments rather than specified actual losses. If a trigger event causes losses exceeding a specific loss amount or magnitude in the geographic region and time period specified in a bond, the fund may lose a portion or all of its accrued interest and/or principal invested in the bond. The fund is entitled to receive principal and interest payments so long as no trigger event occurs of the description and magnitude specified by the instrument. Often event-linked bonds provide for extensions of maturity that are mandatory or optional at the discretion of the issuer, in order to process and audit loss claims in those cases when a trigger event has, or possibly has, occurred. The typical duration of mandatory and optional extension of maturity for event linked bonds currently is between three to six months, but maturity may be extended for a period of up to two years. In rare circumstances, the extension may exceed two years. In addition to the specified trigger events, event linked bonds may also expose the fund to certain unanticipated risks, including but not limited to issuer (credit) default, adverse regulatory or jurisdictional interpretations and adverse tax consequences. Event-linked bonds are subject to the risk that the model used to calculate the probability of a trigger event was not accurate and underestimated the "rating" or likelihood of a trigger event.

Below investment grade debt securities involve greater risk of loss, are subject to greater price volatility and are less liquid, especially during periods of economic uncertainty or change, than higher rated debt securities. The fund may invest in high yield securities of any rating, including securities that are in default at the time of purchase. Securities with floating interest rates generally are less sensitive to interest rate changes but may decline in value if their interest rates do not rise as much, or as quickly, as prevailing interest rates. Unlike fixed rate securities, floating rate securities generally will not increase in value if interest rates decline. Changes in interest rates also will affect the amount of interest income the fund earns on its floating rate investments.

Pioneer Funds Distributor, Inc., is the Underwriter and Distributor for Pioneer open-end mutual funds, 60 State Street, Boston, MA 02109, Member SIPC, Member of the UniCredito Italiano Banking Group, Register of Banking Groups.

(c)2007 Pioneer Investment Management, Inc.

Member of the UniCredito Italiano Banking Group, Register of Banking Groups