Summary Prospectus   October 1, 2009

ProShares UltraShort 7-10 Year Treasury  

» Receive investor materials electronically — see inside cover.

PST LISTED ON NYSE ARCA   CUSIP # 74347R313  

This summary prospectus is designed to provide investors with key fund information in a clear and concise format. Before you invest, you may want to review the Fund’s full prospectus, which contains more information about the Fund and its risks. The Fund’s full prospectus and statement of additional information, both dated October 1, 2009, and most recent annual report to shareholders, dated May 31, 2009, are all incorporated by reference into this Summary Prospectus. All this information may be obtained at no cost either: online at http://www.proshares.com/resources/lit-center; by calling 866-PRO-5125 (866-776-5125) (financial professionals should call 888-PRO-5717 (888-776-5717)); or by sending an e-mail request to info@proshares.com.

Electronic Delivery

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Your information will be kept confidential and will not be used for any purpose other than electronic delivery. If you change your mind, you can cancel electronic delivery at any time and revert to physical delivery of your materials. Just go to www.icsdelivery.com, perform the first three steps above, and follow the instructions for cancelling electronic delivery. If you have any questions, please contact your brokerage firm.

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Important Information About the Fund

ProShares UltraShort 7-10 Year Treasury (the “Fund”) seeks investment results for a single day only, not for longer periods. This means that the return of the Fund for a period longer than a single trading day will be the result of each day’s returns compounded over the period, which will very likely differ from twice the inverse of the return of the Barclays Capital 7-10 Year U.S. Treasury Bond Index (the “Index”) for that period. In periods of higher market volatility, the volatility of the benchmark may be at least as important to the Fund’s return for the period as the return of the benchmark. The Fund is different from most exchange-traded funds in that it seeks inverse leveraged returns and only on a daily basis. The Fund also is riskier than similarly benchmarked exchange-traded funds that do not use leverage. Accordingly, the Fund may not be suitable for all investors and should be used only by knowledgeable investors who understand the potential consequences of seeking daily inverse leveraged investment results. Shareholders should actively monitor their investments.

Investment Objective

The Fund seeks daily investment results, before fees and expenses and interest income earned on cash and financial instruments, that correspond to twice (200%) the inverse (opposite) of the daily performance of the Index. The Fund does not seek to achieve its stated investment objective over a period of time greater than one day.

Fees and Expenses of the Fund

The table below describes the fees and expenses that you may pay if you buy or hold shares of the Fund (“Shares”).

Shareholder Fees (fees paid directly from your investment)
Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment)
Investment Advisory Fees	0.75%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.26%
Total Gross Annual Operating Expenses	1.01%
Fee Waiver/Reimbursement*	-0.06%
Total Net Annual Operating Expenses	0.95%

* ProShare Advisors LLC (“ProShare Advisors”) has contractually agreed to waive Investment Advisory and Management Services Fees and to reimburse other expenses to the extent Total Gross Annual Operating Expenses, as a percentage of average daily net assets, exceed 0.95% through September 30, 2010. After such date, the expense limitation may be terminated or revised. Amounts waived or reimbursed in a particular contractual period may be recouped by ProShare Advisors within five years of the end of that contractual period to the extent that recoupment will not cause the Fund’s expenses to exceed any expense limitation in place at that time. A waiver or reimbursement lowers the expense ratio and increases overall returns to investors.

Example: This example is intended to help you compare the cost of investing in shares of 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 each period. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, which exclude brokerage commissions, remain the same. Although your actual cost may be higher or lower, based on these assumptions your approximate costs would be:

1 Year	3 Years	5 Years	10 Years
$97	$316	$552	$1,231

Investors may pay brokerage commissions on their purchases and sales of Fund shares, which are not reflected in the example or the table above.

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover 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 entire portfolio turnover rate was 0 % of the average value of its whole portfolio. However, this portfolio turnover rate is calculated without regard to cash instruments or derivatives. If such instruments were included, the Fund’s portfolio turnover rate would be significantly higher.

Principal Investment Strategies

The Fund invests in derivatives that ProShare Advisors believes should have similar daily performance characteristics as twice (200%) the inverse of the daily return of the Index. The Index includes all publicly issued, U.S. Treasury securities that have a remaining maturity of between 7 and 10 years, are non-convertible, are denominated in U.S. dollars, are rated (at least Baa3 by Moody’s Investors Service or BBB- by S&P), are fixed rate, and have more than $250 million par outstanding. The Index is weighted by the relative market value of all securities meeting the Index criteria. Excluded from the Index are certain special issues, such as flower bonds, targeted investor notes (TINs), U.S. Treasury inflation-protected securities (TIPs), state and local government bonds (SLGs), and coupon issues that have been stripped from assets already included. The Index is published under the Bloomberg ticker symbol “LT09TRUU.” Assets of the Fund not invested in derivatives will typically be held in money market instruments.

• Derivatives — The Fund invests in financial instruments whose value is derived from the value of an underlying asset, interest rate or index. The Fund invests in derivatives as a substitute for directly shorting debt in order to gain inverse leveraged exposure to the Index. Derivatives may include:

^¡ Futures Contracts — Contracts that pay a fixed price for an agreed-upon amount of securities or the cash value of the securities, on an agreed-upon date.

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^¡ Swap Agreements — Contracts entered into primarily with institutional investors for a specified period ranging from a day to more than one year. In a standard “swap” transaction, two parties agree to exchange the returns (or differentials in rates of return) earned or realized on particular predetermined investments or instruments. The gross returns to be exchanged or “swapped” between the parties are calculated with respect to a “notional amount,” e.g., the return on or change in value of a particular dollar amount invested in a “basket” of securities representing a particular index.

• Money Market Instruments — The Fund invests in short-term cash instruments that have terms to maturity of less than 397 days and exhibit high quality credit profiles.

ProShare Advisors uses a mathematical approach to investing. Using this approach, ProShare Advisors determines the type, quantity and mix of investment positions that the Fund should hold to approximate the performance of its benchmark. The Fund may gain exposure to only a representative sample of the securities in the underlying index, which is intended to have aggregate characteristics similar to those of the underlying index. ProShare Advisors does not invest the assets of the Fund in securities or derivatives based on ProShare Advisors’ view of the investment merit of a particular security, instrument, or company, nor does it conduct conventional stock research or analysis (other than in determining counterparty creditworthiness), or forecast stock market movement or trends, in managing the assets of the Fund. The Fund seeks to remain fully invested at all times in securities and/or derivatives that provide exposure to its underlying index without regard to market conditions, trends or direction.

At the close of the markets each trading day, the Fund will seek to position its portfolio so that its exposure to its benchmark is consistent with the Fund’s investment objective. The impact of the Index’s movements during the day will affect whether the Fund’s portfolio needs to be re-positioned. For example, if the Index has risen on a given day, net assets of the Fund should fall, meaning that the Fund’s exposure will need to be decreased. Conversely, if the Index has fallen on a given day, net assets of the Fund should rise, meaning the Fund’s exposure will need to be increased.

The Fund will concentrate its investment in a particular industry or group of industries to approximately the same extent as the Index is so concentrated.

Principal Risks

You could lose money by investing in the Fund.

• Risk Associated with the Use of Leverage — The Fund uses investment techniques and derivatives that may be considered aggressive because the Fund’s investment in derivatives may involve a small investment relative to the amount of investment exposure assumed and may result in losses exceeding the amounts invested in those instruments. Particularly when used to create leverage, the use of derivatives may expose the Fund to potentially dramatic changes (losses or gains) in the value of the instruments and imperfect correlation between the value of the instruments and the relevant security or index.

• Concentration Risk — The Fund will typically concentrate its investments in issuers of one or more particular industries to the same extent that its underlying index is so concentrated and to the extent permitted by applicable regulatory guidance. There is a risk that those issuers (or industry sector) will perform poorly and negatively impact the Fund. Concentration risk results from maintaining exposure (long or short) to issuers conducting business in a specific industry. The risk of concentrating investments in a limited number of issuers in a particular industry is that the Fund will be more susceptible to the risks associated with that industry than a fund that does not concentrate its investments.

• Correlation and Compounding Risk — A number of factors may affect the Fund’s ability to achieve a high degree of correlation with its benchmark, and there can be no guarantee that the Fund will achieve a high degree of correlation. Failure to achieve a high degree of correlation may prevent the Fund from achieving its investment objective. The risk of the Fund not achieving its daily investment objective will be more acute when the Index has an extreme one-day move approaching 50%. In addition, as a result of compounding, because the Fund has a single day investment objective, the Fund’s performance for periods greater than one day is likely to be either greater than or less than the index performance times the stated multiple in the Fund objective, before accounting for fees and fund expenses.

Compounding affects all investments, but has a more significant impact on a leveraged fund. In general, particularly during periods of higher index volatility, compounding will cause longer term results to be more or less than twice the inverse of the return of the index. This effect becomes more pronounced as volatility increases.

Fund performance for periods greater than one day can be estimated given any set of assumptions for the following factors: a) index performance; b) index volatility; c) financing rates associated with leverage; d) other Fund expenses; e) dividends paid by companies in the index; and f) period of time. The chart below illustrates the impact of two principal factors—volatility and performance—on Fund performance. The chart shows estimated Fund returns for a number of combinations of performance and volatility over a one-year period. Performance shown in the chart assumes: (a) no dividends paid by the companies included in the index; (b) no Fund expenses; and (c) borrowing/lending rates (to obtain leverage) of zero percent. If Fund expenses were included, the Fund’s performance would be lower than shown.

Areas shaded lighter represent those scenarios where the Fund can be expected to return more than twice the inverse performance of the Index; conversely, areas shaded darker represent those scenarios where the Fund can be expected to return less than twice the inverse performance of the Index.

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Performance		Volatility Rate
One Year Index	-200% One Year Index	10%	25%	50%	75%	100%
-60%	-120%	506.5%	418.1%	195.2%	15.6%	-68.9%
-50%	-100%	288.2%	231.6%	88.9%	-26.0%	-80.1%
-40%	-80%	169.6%	130.3%	31.2%	-48.6%	-86.2%
-30%	-60%	98.1%	69.2%	-3.6%	-62.2%	-89.8%
-20%	-40%	51.6%	29.5%	-26.2%	-71.1%	-92.2%
-10%	-20%	19.8%	2.3%	-41.7%	-77.2%	-93.9%
0%	0%	-3.0%	-17.1%	-52.8%	-81.5%	-95.0%
10%	20%	-19.8%	-31.5%	-61.0%	-84.7%	-95.9%
20%	40%	-32.6%	-42.4%	-67.2%	-87.2%	-96.5%
30%	60%	-42.6%	-50.9%	-72.0%	-89.1%	-97.1%
40%	80%	-50.5%	-57.7%	-75.9%	-90.6%	-97.5%
50%	100%	-56.9%	-63.2%	-79.0%	-91.8%	-97.8%
60%	120%	-62.1%	-67.6%	-81.5%	-92.8%	-98.1%

The Index’s annualized historical volatility rate for the five year period ended June 30, 2009 is: 6.97%. The Index’s annualized performance for the five year period ended June 30, 2009 is: 6.07%.

Historical Index volatility and performance are not indications of what the Index volatility and performance will be in the future.

For additional graphs and charts demonstrating the effects of volatility and index performance on the long-term performance of the Fund, see “Principal Risks of Leveraged and Inverse Leveraged Funds and the Impact of Compounding” in the Fund’s full prospectus and “Special Note Regarding the Correlation Risks of Leveraged Funds” in the Fund’s Statement of Additional Information.

• Counterparty Risk — The Fund will be subject to the credit risk (that is, where changes in an issuer’s financial strength or the credit rating of a financial instrument it issues may affect an instrument’s value) with respect to the amount it expects to receive from counterparties to derivatives and repurchase agreements entered into by the Fund or held by special purpose or structured vehicles. If a counterparty becomes bankrupt or otherwise fails to perform its obligations due to financial difficulties, the value of your investment in the Fund may decline.

• Debt Instrument Risk — The Fund may invest in, or seek exposure to, debt instruments. Debt instruments may have varying levels of sensitivity to changes in interest rates, credit risk and other factors. Typically, the value of outstanding debt instruments falls when interest rates rise. Debt instruments with longer maturities may fluctuate more in response to interest rate changes than instruments with shorter maturities. Many types of debt instruments are subject to prepay-

ment risk, which is the risk that the issuer of the security will repay principal prior to the maturity date. Debt instruments allowing prepayment may offer less potential for gains during a period of declining interest rates. In addition, changes in the credit quality of the issuer of a debt instrument can also affect the price of a debt instrument, as can an issuer’s default on its payment obligations. Such factors may cause the value of an investment in the Fund to decrease. Also, the securities of certain U.S. government agencies, authorities or instrumentalities in which the Fund may invest are neither issued by nor guaranteed as to principal and interest by the U.S. government, and may be exposed to credit risk.

• Early Close/Late Close/Trading Halt Risk — An exchange or market may close early, close late or issue trading halts on specific securities, or the ability to buy or sell certain securities or derivatives may be restricted, which may result in the Fund being unable to buy or sell certain securities or derivatives. In such circumstances, the Fund may be unable to rebalance its portfolio, may be unable to accurately price its investments and/or may incur substantial trading losses.

• Interest Rate Risk — Interest rate risk is the risk that debt securities or certain financial instruments may fluctuate in value due to changes in interest rates. Commonly, investments subject to interest rate risk will decrease in value when interest rates rise and increase in value when interest rates decline. The value of securities with longer maturities may fluctuate more in response to interest rate changes than securities with shorter maturities.

• Inverse Correlation Risk — Shareholders should lose money when the Index rises—a result that is the opposite from traditional funds.

• Liquidity Risk — In certain circumstances, such as the disruption of the orderly markets for the securities or derivatives in which the Fund invests, the Fund might not be able to dispose of certain holdings quickly or at prices that represent true market value in the judgment of ProShare Advisors. Such a situation may prevent the Fund from limiting losses, realizing gains or achieving a high inverse correlation with its underlying index.

• Market Risk — The Fund is subject to market risks that will affect the value of its Shares, including adverse issuer, political, regulatory, market or economic developments, as well as developments that impact specific economic sectors, industries or segments of the market.

• Market Price Variance Risk — Fund Shares will be listed for trading on the NYSE Arca (“Exchange”) and can be bought and sold in the secondary market at market prices. The market prices of Shares will fluctuate in response to changes in net asset value (“NAV”) and supply and demand for Shares. ProShare Advisors cannot predict whether Shares will trade above, below or at their NAV. Given the fact that Shares can be created and redeemed in Creation Units, ProShare Advisors believes that large discounts or premiums to the NAV of Shares should not be sustained. The Fund’s investment results are measured based upon the daily NAV of the Fund. Investors purchasing and selling shares in the secondary market may not experience

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investment results consistent with those experienced by those creating and redeeming directly with the Fund.

• Non-Diversification Risk — The Fund is classified as “non-diversified” under the Investment Company Act of 1940 (“1940 Act”), and has the ability to invest a relatively high percentage of its investments in the securities of a small number of issuers if there is a small number of issuers in the underlying index or if ProShare Advisors determines that doing so is the most efficient means of meeting the Fund’s objective. This makes the performance of the Fund more susceptible to a single economic, political or regulatory event than a diversified fund might be. This risk may be particularly acute when the Fund’s underlying index comprises a small number of stocks or other securities.

• Portfolio Turnover Risk — Daily rebalancing of Fund holdings, which is required to keep leverage consistent with a one-day investment objective, will cause a higher level of portfolio transactions than compared to most exchange-traded funds. Additionally, active market trading of Shares may cause more frequent creation or redemption activities that could, in certain circumstances, increase the number of portfolio transactions. High levels of transactions increase brokerage costs and may result in increased taxable capital gains.

Investment Results

Performance history will be available for the Fund after it has been in operation for a full calendar year.

Management

The Fund is advised by ProShare Advisors and is managed by the following individuals.

Portfolio Manager	Experience with the Advisor	Title with the Advisor
Todd Johnson	Since June 2008	Chief Investment Officer
Howard S. Rubin, CFA	Since December 2007	Senior Portfolio Manager
Michelle Liu	Since November 2007	Associate Portfolio Manager

Purchase and Sale of Fund Shares

The Fund will issue and redeem Shares only to Authorized Participants (typically, broker-dealers) in exchange for the deposit or delivery of a basket of assets (securities and/or cash) in large blocks, known as Creation Units, each of which is comprised of 75,000 Shares. Retail investors may only purchase and sell Fund Shares on a national securities exchange through a broker-dealer. Because the Shares trade at market prices rather than net asset value, Shares may trade at a price greater than net asset value (premium) or less than net asset value (discount).

Tax Information

Income and capital gain distributions you receive from the Fund are subject to federal income taxes and may also be subject to state and local taxes. Distributions for this Fund may be significantly higher than those of most exchange-traded funds.

Investment Company Act file number 811-2114

ProShares^®

ProShares Trust

7501 Wisconsin Avenue, Suite 1000 Bethesda, MD 20814

866.PRO.5125    866.776.5125

www.proshares.com

© 2009 ProShare Advisors LLC. All rights reserved. PST-OCT09