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STATEMENT OF ADDITIONAL INFORMATION

UNITED STATES OIL FUND, LP

Before you decide whether to invest, you should read this entire prospectus carefully and consider the risk factors beginning on page 11.

This prospectus is in two parts: a disclosure document and a statement of additional information. These parts are bound together, and both parts contain important information.

This statement of additional information and accompanying disclosure document are both dated June 11, 2012.

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UNITED STATES OIL FUND, LP

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The Commodity Interest Markets

General

The CEA governs the regulation of commodity interest transactions, markets and intermediaries. The CEA provides for varying degrees of regulation of commodity interest transactions depending upon: (1) the type of instrument being traded (e.g., contracts for future delivery, options, swaps or spot contracts), (2) the type of commodity underlying the instrument (distinctions are made between instruments based on agricultural commodities, energy and metals commodities and financial commodities), (3) the nature of the parties to the transaction (retail, eligible contract participant, or eligible commercial entity), (4) whether the transaction is entered into on a principal-to-principal or intermediated basis, (5) the type of market on which the transaction occurs, and (6) whether the transaction is subject to clearing through a clearing organization.

The offer and sale of units of USOF, as well as units of each of the Related Public Funds, is registered under the Securities Act. USOF and the Related Public Funds are subject to the requirements of the Securities Act, the Exchange Act and the rules and regulations adopted thereunder as administered by the SEC. Firms’ participation in the distribution of units are regulated as described above, as well as by the self regulatory association, FINRA.

Futures Contracts

A futures contract is a standardized contract traded on, or subject to the rules of, an exchange that calls for the future delivery of a specified quantity and type of a commodity at a specified time and place. Futures contracts are traded on a wide variety of commodities, including agricultural products, bonds, stock indices, interest rates, currencies, energy and metals. The size and terms of futures contracts on a particular commodity are identical and are not subject to any negotiation, other than with respect to price and the number of contracts traded between the buyer and seller.

The contractual obligations of a buyer or seller may generally be satisfied by taking or making physical delivery of the underlying commodity or by making an offsetting sale or purchase of an identical futures contract on the same or linked exchange before the designated date of delivery. The difference between the price at which the futures contract is purchased or sold and the price paid for the offsetting sale or purchase, after allowance for brokerage commissions, constitutes the profit or loss to the trader. Some futures contracts, such as stock index contracts, settle in cash (reflecting the difference between the contract purchase/sale price and the contract settlement price) rather than by delivery of the underlying commodity.

In market terminology, a trader who purchases a futures contract is long in the market and a trader who sells a futures contract is short in the market. Before a trader closes out his long or short position by an offsetting sale or purchase, his outstanding contracts are known as open trades or open positions. The aggregate amount of open positions held by traders in a particular contract is referred to as the open interest in such contract.

Forward Contracts

A forward contract is a contractual obligation to purchase or sell a specified quantity of a commodity at or before a specified date in the future at a specified price and, therefore, is economically similar to a futures contract. Unlike futures contracts, however, forward contracts are typically traded in the over-the-counter markets and are not standardized contracts. Forward contracts for a given commodity are generally available for various amounts and maturities and are subject to individual negotiation between the parties involved. Moreover, generally there is no direct means of offsetting or closing out a forward contract by taking an offsetting position as one would a futures contract on a U.S. exchange. If a trader desires to close out a forward contract position, he generally will establish an opposite position in the contract but will settle and recognize the profit or loss on both positions simultaneously on the delivery date. Thus, unlike in the futures contract market where a trader who has offset positions will recognize profit or loss immediately, in the forward market a trader with a position that has been offset at a profit will generally not receive such profit until the delivery date, and likewise a trader with a

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position that has been offset at a loss will generally not have to pay money until the delivery date. In recent years, however, the terms of forward contracts have become more standardized, and in some instances such contracts now provide a right of offset or cash settlement as an alternative to making or taking delivery of the underlying commodity.

To date, the forward markets have been largely unregulated, forward contracts have been executed bilaterally and, in general, forward contracts have not been cleared or guaranteed by a third party. While recently adopted laws and regulations may require certain forward contracts to be cleared through regulated clearing organizations, absent such clearing organizations, USOF’s trading in forward contracts will be exposed to the creditworthiness of the counterparties on the other side of the trade.

Options on Futures Contracts

Options on futures contracts are standardized contracts traded on an exchange. An option on a futures contract gives the buyer of the option the right, but not the obligation, to take a position at a specified price (the striking, strike, or exercise price) in the underlying futures contract or underlying interest. The buyer of a call option acquires the right, but not the obligation, to purchase or take a long position in the underlying interest, and the buyer of a put option acquires the right, but not the obligation, to sell or take a short position in the underlying interest.

The seller, or writer, of an option is obligated to take a position in the underlying interest at a specified price opposite to the option buyer if the option is exercised. Thus, the seller of a call option must stand ready to take a short position in the underlying interest at the strike price if the buyer should exercise the option. The seller of a put option, on the other hand, must stand ready to take a long position in the underlying interest at the strike price.

A call option is said to be in-the-money if the strike price is below current market levels and out-of-the-money if the strike price is above current market levels. Conversely, a put option is said to be in-the-money if the strike price is above the current market levels and out-of-the-money if the strike price is below current market levels.

Options have limited life spans, usually tied to the delivery or settlement date of the underlying interest. Some options, however, expire significantly in advance of such date. The purchase price of an option is referred to as its premium, which consists of its intrinsic value (which is related to the underlying market value) plus its time value. As an option nears its expiration date, the time value shrinks and the market and intrinsic values move into parity. An option that is out-of-the-money and not offset by the time it expires becomes worthless. On certain exchanges, in-the-money options are automatically exercised on their expiration date, but on others unexercised options simply become worthless after their expiration date.

Regardless of how much the market swings, the most an option buyer can lose is the option premium. The option buyer deposits his premium with his broker, and the money goes to the option seller. Option sellers, on the other hand, face risks similar to participants in the futures markets. For example, since the seller of a call option is assigned a short futures position if the option is exercised, his risk is the same as someone who initially sold a futures contract. Because no one can predict exactly how the market will move, the option seller posts margin to demonstrate his ability to meet any potential contractual obligations.

Options on Forward Contracts or Commodities

Options on forward contracts or commodities operate in a manner similar to options on futures contracts. An option on a forward contract or commodity gives the buyer of the option the right, but not the obligation, to take a position at a specified price in the underlying forward contract or commodity. However, similar to forward contracts, options on forward contracts or on commodities are individually negotiated contracts between

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counterparties and are typically traded in the over-the-counter market. Therefore, options on forward contracts and physical commodities possess many of the same characteristics of forward contracts with respect to offsetting positions and credit risk that are described above.

Swap Contracts

Swap transactions generally involve contracts between two parties to exchange a stream of payments computed by reference to a notional amount and the price of the asset that is the subject of the swap. Swap contracts are principally traded off-exchange, although certain swap contracts are also traded in electronic trading facilities and cleared through clearing organizations.

Swaps are usually entered into on a net basis, that is, the two payment streams are netted out in a cash settlement on the payment date or dates specified in the agreement, with the parties receiving or paying, as the case may be, only the net amount of the two payments. Swaps do not generally involve the delivery of underlying assets or principal. Accordingly, the risk of loss with respect to swaps is generally limited to the net amount of payments that the party is contractually obligated to make. In some swap transactions one or both parties may require collateral deposits from the counterparty to support that counterparty’s obligation under the swap agreement. If the counterparty to such a swap defaults, the risk of loss consists of the net amount of payments that the party is contractually entitled to receive less any collateral deposits it is holding.

Some swap transactions are cleared through central counterparties. These transactions, known as cleared swaps, involve two counterparties first agreeing to the terms of a swap transaction, then submitting the transaction to a clearing house that acts as the central counterparty. Once accepted by the clearing house, the original swap transaction is novated and the central counterparty becomes the counterparty to a trade with each of the original parties based upon the trade terms determined in the original transaction. In this manner each individual swap counterparty reduces its risk of loss due to counterparty nonperformance because the clearing house acts as the counterparty to each transaction.

Regulation

Futures exchanges in the United States are subject to varying degrees of regulation under the CEA depending on whether such exchange is a designated contract market, exempt board of trade or electronic trading facility. Clearing organizations are also subject to the CEA and the rules and regulations adopted thereunder and administered by the CFTC. The CFTC is the governmental agency charged with responsibility for regulation of futures exchanges and commodity interest trading conducted on those exchanges. The CFTC’s function is to implement the CEA’s objectives of preventing price manipulation and excessive speculation and promoting orderly and efficient commodity interest markets. In addition, the various exchanges and clearing organizations themselves exercise regulatory and supervisory authority over their member firms.

The CFTC also regulates the activities of “commodity trading advisors” and “commodity pool operators” and the CFTC has adopted regulations with respect to certain of such persons’ activities. Pursuant to its authority, the CFTC requires a CPO, such as the General Partner, to keep accurate, current and orderly records with respect to each pool it operates. The CFTC may suspend, modify or terminate the registration of any registrant for failure to comply with CFTC rules or regulations. Suspension, restriction or termination of the General Partner registration as a CPO would prevent it, until such time (if any) as such registration were to be reinstated, from managing, and might result in the termination of, USOF or the Related Public Funds.

The CEA also gives the states certain powers to enforce its provisions and the regulations of the CFTC.

Under certain circumstances, the CEA grants unitholders the right to institute a reparations proceeding before the CFTC against the General Partner (as a registered commodity pool operator), as well as those of their respective employees who are required to be registered under the CEA. Unitholders may also be able to maintain a private right of action for certain violations of the CEA.

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Pursuant to authority in the CEA, the NFA has been formed and registered with the CFTC as a registered futures association. The NFA is the only self regulatory association for commodities professionals other than the exchanges. As such, the NFA promulgates rules governing the conduct of commodity professionals and disciplines those professionals that do not comply with such standards. The CFTC has delegated to the NFA responsibility for the registration of commodity pool operation. The General Partner is a member of the NFA. As a member of the NFA, the General Partner is subject to NFA standards relating to fair trade practices, financial condition, and consumer protection. The CFTC is prohibited by statute from regulating trading on foreign commodity exchanges and markets.

The CEA requires all futures commission merchants, such as USOF’s clearing brokers, to meet and maintain specified fitness and financial requirements, to segregate customer funds from proprietary funds and account separately for all customers’ funds and positions, and to maintain specified books and records open to inspection by the staff of the CFTC. The CFTC has similar authority over introducing brokers, or persons who solicit or accept orders for commodity interest trades but who do not accept margin deposits for the execution of trades. The CEA authorizes the CFTC to regulate trading by futures commission merchants and by their officers and directors, permits the CFTC to require action by exchanges in the event of market emergencies, and establishes an administrative procedure under which customers may institute complaints for damages arising from alleged violations of the CEA. The CEA also gives the states powers to enforce its provisions and the regulations of the CFTC.

The regulations of the CFTC and the NFA prohibit any representation by a person registered with the CFTC or by any member of the NFA, that registration with the CFTC, or membership in the NFA, in any respect indicates that the CFTC or the NFA, as the case may be, has approved or endorsed that person or that person’s trading program or objectives. The registrations and memberships of the parties described in this summary must not be considered as constituting any such approval or endorsement. Likewise, no futures exchange has given or will give any similar approval or endorsement.

The regulation of commodity interest trading in the United States and other countries is an evolving area of the law. The various statements made in this summary are subject to modification by legislative action and changes in the rules and regulations of the CFTC, the NFA, the futures exchanges, clearing organizations and other regulatory bodies.

On July 21, 2010, a broad financial regulatory reform bill, the Dodd-Frank Act, was signed into law. All of the Dodd-Frank Act’s provisions became effective on July 16, 2011, but the actual implementation of some of the provisions is subject to continuing uncertainty because implementing rules and regulations have not been completely finalized and have been challenged in court. Pending final resolution of all applicable regulatory requirements, some specific examples of how the new Dodd-Frank Act provisions and rules adopted thereunder could impact USOF are discussed below.

Futures Contracts and Position Limits

Provisions in the Dodd-Frank Act include the requirement that position limits be established on a wide range of commodity interests including energy-based and other commodity futures contracts, certain cleared commodity swaps and certain over-the-counter commodity contracts; new registration, recordkeeping, capital and margin requirements for “swap dealers” and “major swap participants” as determined by the new law and applicable regulations; and the forced use of clearinghouse mechanisms for most swap transactions that are currently entered into in the over-the-counter market. The new law and the rules thereunder may negatively impact USOF’s ability to meet its investment objective either through limits or requirements imposed on it or upon its counterparties. Further, increased regulation of, and the imposition of additional costs on, swap transactions under the new legislation and implementing regulations could cause a reduction in the swap market and the overall derivatives markets, which could restrict liquidity and adversely affect USOF. In particular, new position limits imposed on USOF or its counterparties may impact USOF’s ability to invest in a manner that most

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efficiently meets its investment objective, and new requirements, including capital and mandatory clearing, may increase the cost of USOF’s investments and doing business, which could adversely impact the ability of USOF to achieve its investment objective.

On October 18, 2011, the CFTC adopted regulations implementing position limits and limit formulas for 28 core physical commodity futures contracts, including the Futures Contracts and options on Futures Contracts executed pursuant to the rules of designated contract markets (i.e., certain regulated exchanges) and commodity swaps that are economically equivalent to such futures and options contracts (collectively, “Referenced Contracts”). The new regulations require, among other things, aggregation of position limits that would apply across different trading venues to contracts based on the same underlying commodity. However, the regulations do not appear to require aggregation of Referenced Contracts held by separate Related Public Funds.

Although the regulations are effective on January 17, 2012, the position limit rules will be implemented in two phases: spot-month position limits and non-spot-month position limits. Spot-month limits will be effective sixty days after the term “swap” is defined under the Dodd-Frank Act (see below). The limits adopted will be based on the spot-month position limit levels currently in place at applicable futures exchanges (or designated contract market or “DCM”). Thereafter, the spot-month limits will be adjusted annually for energy contracts. These subsequent limits will be based on the CFTC’s determination of deliverable supply in consultation with the futures exchanges. Spot-month position limit levels will be set generally at 25% of estimated deliverable supply, and limits will be applied separately for physical-delivery and cash-settled contracts in the same commodity.

Non-spot-month position limits will go into effect by CFTC order after the CFTC has received one year of open interest data on physical commodity cleared and uncleared swaps under the swaps large trader reporting rule. The non-spot month limits will be adjusted biennially based on Referenced Contract open interest. Non-spot-month position limits (i.e., limits applied to positions in all contract months combined or in a single contract month) will be set using the 10/2.5 percent formula: 10 percent of the contract’s first 25,000 of open interest and 2.5 percent thereafter. These limits will be reset biennially based on two years of open interest data.

On December 2, 2011, the Securities Industry and Financial Markets Association (“SIFMA”) and the International Swaps and Derivatives Association (“ISDA”) filed a lawsuit challenging the CFTC’s position limits rule. The lawsuit asserts that the position limits rule inadequately fulfills the required cost-benefit analysis. It is not known at this time what effect this lawsuit will have on the implementation of the new position limits rule.

Based on its current understanding of the final position limit regulations, the General Partner does not anticipate significant negative impact on the ability of USOF to achieve its investment objective.

“Swap” Transactions

The Dodd-Frank Act imposes new regulatory requirements on certain “swap” transactions that USOF is authorized to engage in that may ultimately impact the ability of USOF to meet its investment objective. On April 27, 2011, the CFTC and the SEC proposed joint rules defining the term “swap” and thus providing more clarity regarding which transactions will be regulated as such under the Dodd-Frank Act. However, the CFTC and SEC have not implemented final regulations on this issue and it is therefore still uncertain which types of transactions will be ultimately regulated as “swaps.”

The Dodd-Frank Act requires that certain transactions ultimately falling within the definition of “swap” be executed on organized exchanges or “swap execution facilities” and cleared through regulated clearing organizations (which are referred to in the Dodd-Frank Act as “derivative clearing organizations”). However, as described above, it is currently unknown which swaps will be subject to such trading and clearing requirements. If a swap is required to be cleared, the initial margin will be set by the clearing organization, subject to certain regulatory requirements and guidelines. Initial and variation margin requirements for swap dealers and major swap participants who enter into uncleared swaps and capital requirements for swap dealers and major swap

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participants who enter into both cleared and uncleared trades will be set by the CFTC, the SEC or the applicable Prudential Regulator. On July 25, 2011, the CFTC adopted final regulations to determine which entities will be regulated as “swap dealers” and “major swap participants” and thus have to comply with these capital and margin requirements (as well as a multitude of other requirements under the Dodd-Frank Act). In general, increased regulation of, and the imposition of additional costs on, swap transactions could have an adverse effect on USOF by, for example, reducing the size of and therefore liquidity in the derivatives market, increasing transaction costs and decreasing the ability to customize derivative transactions. The final rule regarding review of swaps for mandatory clearing went effective September 26, 2011.

On July 14, 2011, the CFTC issued an order providing temporary relief from certain swaps-related provisions of Title VII that would have automatically taken effect on July 16, 2011. The final order granted temporary exemptive relief that, by its terms, expires upon the earlier of the effective date of the required final rulemaking or December 31, 2011. On October 18, 2011, the CFTC issued an order, which modifies the July 14, 2011 order by extending the temporary exemptive relief to the earlier of the effective date of the required final rulemaking or July 16, 2012.

On February 7, 2012, the CFTC published a rule requiring each futures commission merchant (“FCM”) and derivative clearing organization (“DCO”) to segregate cleared swaps and related collateral posted by a customer of the FCM from the assets of the FCM or DCO, although such property can be commingled with the property of other cleared swaps customers of the FCM or DCO. This rule addresses losses incurred by a DCO in a so-called “double default” scenario in which a customer of an FCM defaults in its obligations to the FCM and the FCM, in turn, defaults in its obligations to the DCO. Under this scenario, the DCO can only access the collateral attributable to other customers of the DCO whose cleared swap positions are in a loss position following the primary customer’s default. This rule is scheduled to become effective on November 8, 2012. Some market participants have expressed concern that the requirements of this segregation rule may result in higher initial margins or higher fees. USOF does not anticipate any impact to its operations in order to meet the requirements of the new rule.

Additionally, the CFTC published rules on February 17, 2012 and April 3, 2012 that require “swap dealers” and “major swap participants” to: 1) adhere to business conduct standards, 2) implement policies and procedures to ensure compliance with the Commodity Exchange Act, 3) maintain records of such compliance. These new requirements may impact the documentation requirements for both cleared and non-cleared swaps and cause swap dealers and major swap participants to face increased compliance costs that, in turn, may be passed along to counterparties (such as USOF) in the form of higher fees and expenses that related to trading swaps.

Finally, on February 24, 2012, the CFTC amended certain disclosure obligations to require that the operator of a commodity pool that invests in swaps include standardized swap risk disclosures in the pool’s disclosure documents by December 31, 2012.

The effect of the future regulatory change on USOF is impossible to predict, but it could be substantial and adverse.

Commodity Margin

Original or initial margin is the minimum amount of funds that must be deposited by a commodity interest trader with the trader’s broker to initiate and maintain an open position in futures contracts. Maintenance margin is the amount (generally less than the original margin) to which a trader’s account may decline before he must deliver additional margin. A margin deposit is like a cash performance bond. It helps assure the trader’s performance of the futures contracts that he or she purchases or sells. Futures contracts are customarily bought and sold on initial margin that represents a very small percentage (ranging upward from less than 5%) of the aggregate purchase or sales price of the contract. Because of such low margin requirements, price fluctuations occurring in the futures markets may create profits and losses that, in relation to the amount invested, are greater

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than are customary in other forms of investment or speculation. As discussed below, adverse price changes in the futures contract may result in margin requirements that greatly exceed the initial margin. In addition, the amount of margin required in connection with a particular futures contract is set from time to time by the exchange on which the contract is traded and may be modified from time to time by the exchange during the term of the contract.

Brokerage firms, such as USOF’s clearing brokers, carrying accounts for traders in commodity interest contracts may not accept lower, and generally require higher, amounts of margin as a matter of policy to further protect themselves. The clearing brokers require USOF to make margin deposits equal to exchange minimum levels for all commodity interest contracts. This requirement may be altered from time to time in the clearing brokers’ discretion.

Trading in the over-the-counter markets where no clearing facility is provided generally does not require margin but generally does require the extension of credit between counterparties. This extension of credit is generally secured by transfers of collateral and/or independent amounts. Collateral is transferred between counterparties during the term of an over-the-counter transaction based upon the changing value of the transaction, while independent amounts are fixed amounts posted by one or both counterparties at the start of an over-the-counter transaction.

When a trader purchases an option, there is no margin requirement; however, the option premium must be paid in full. When a trader sells an option, on the other hand, he or she is required to deposit margin in an amount determined by the margin requirements established for the underlying interest and, in addition, an amount substantially equal to the current premium for the option. The margin requirements imposed on the selling of options, although adjusted to reflect the probability that out-of-the-money options will not be exercised, can in fact be higher than those imposed in dealing in the futures markets directly. Complicated margin requirements apply to spreads and conversions, which are complex trading strategies in which a trader acquires a mixture of options positions and positions in the underlying interest.

Margin requirements are computed each day by a trader’s clearing broker. When the market value of a particular open commodity interest position changes to a point where the margin on deposit does not satisfy maintenance margin requirements, a margin call is made by the broker. If the margin call is not met within a reasonable time, the broker may close out the trader’s position. With respect to USOF’s trading, USOF (and not its investors personally) is subject to margin calls.

Finally, many major U.S. exchanges have passed certain cross margining arrangements involving procedures pursuant to which the futures and options positions held in an account would, in the case of some accounts, be aggregated and margin requirements would be assessed on a portfolio basis, measuring the total risk of the combined positions.

Potential Advantages of Investment

The Advantages of Non-Correlation

Given that historically, the price of crude oil and of Futures Contracts and Other Oil-Related Investments has had very little correlation to the stock and bond markets, the General Partner believes that the performance of USOF should also exhibit a substantial degree of non-correlation with the performance of traditional equity and debt portfolio components, in part because of the ease of selling commodity interests short. This feature of many commodity interest contracts — being able to be long or short a commodity interest position with similar ease —means that profit and loss from commodity interest trading is not dependent upon economic prosperity or stability.

However, non-correlation will not provide any diversification advantages unless the non-correlated assets are outperforming other portfolio assets, and it is entirely possible that USOF may not outperform other sectors

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of an investor’s portfolio, or may produce losses. Additionally, although adding USOF’s units to an investor’s portfolio may provide diversification, USOF is not a hedging mechanism vis-à-vis traditional debt and equity portfolio components and you should not assume that USOF units will appreciate during periods of inflation or stock and bond market declines.

Non-correlated performance should not be confused with negatively correlated performance. Negative correlation occurs when the performance of two asset classes are in opposite direction to each other. Non-correlation means only that USOF’s performance will likely have little relation to the performance of equity and debt instruments, reflecting the General Partner’s belief that certain factors that affect equity and debt prices may affect USOF differently and that certain factors that affect equity and debt prices may not affect USOF at all. USOF’s net asset value per unit may decline or increase more or less than equity and debt instruments during both rising and falling cash markets. The General Partner does not expect that USOF’s performance will be negatively correlated to general debt and equity markets.

Prior Performance of the General Partner and Related Public Funds.

The General Partner manages the Related Public Funds. Each of the Related Public Funds is a commodity pool that issues units traded on the NYSE Arca. The chart below shows, as of March 31, 2012, the number of Authorized Purchasers, the total number of baskets created and redeemed since inception and the number of outstanding units for each of the Related Public Funds.

The ability of each of the Related Public Funds (other than USOF) to track its benchmark from inception to March 31, 2012 is presented below.

Since the commencement of the offering of USHO units to the public on April 9, 2008 to March 31, 2012, the simple average daily change in its Benchmark Futures Contract was (0.005)%, while the simple average daily change in the NAV of USHO over the same time period was (0.007)%. The average daily difference was 0.002% (or 0.2 basis points, where 1 basis point equals 1/100 of 1%). As a percentage of daily movement of the benchmark futures contract, the average error in daily tracking by the NAV was (0.635)%, meaning that over this time period, USHO’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of USNG units to the public on April 18, 2007 to March 31, 2012, the simple average daily change in its benchmark futures contract was (0.212)% while the simple average daily change in the NAV of USNG over the same time period was (0.213)%. The average daily difference was 0.001% (or 0.1 basis point, where 1 basis point equals 1/100 of 1%). As a percentage of the daily movement of the benchmark futures contract, the average error in daily tracking by the NAV was (0.345)%, meaning that over this time period USNG’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

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Since the commencement of the offering of US12OF units to the public on December 6, 2007 to March 31, 2012, the simple average daily change in the average price of its benchmark futures contracts was 0.010%, while the simple average daily change in the NAV of US12OF over the same time period was 0.018%. The average daily difference was (0.001)%. As a percentage of the daily movement of the average price of the benchmark futures contracts, the average error in daily tracking by the NAV was (0.488)%, meaning that over this time period US12OF’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of UGA units to the public on February 26, 2008 to March 31, 2012, the simple average daily change in its benchmark futures contract was 0.049%, while the simple average daily change in the NAV of UGA over the same time period was 0.047%. The average daily difference was (0.002)% (or (0.2) basis points, where 1 basis point equals 1/100 of 1%). As a percentage of the daily movement of the benchmark futures contract, the average error in daily tracking by the NAV was (0.589)%, meaning that over this time period UGA’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of USSO units to the public on September 24, 2009 to March 31, 2012, the inverse of the simple average daily change in its benchmark futures contract was (0.036)%, while the simple average daily change in the NAV of USSO over the same time period was (0.040)%. The average daily difference was 0.004% (or 0.04 basis points, where 1 basis point equals 1/100 of 1%). As a percentage of the inverse of the daily movement of the benchmark futures contract, the average error in daily tracking by the NAV was (1.354)%, meaning that over this time period USSO’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of US12NG units to the public on November 18, 2009 to March 31, 2012, the simple average daily change in the average price of its benchmark futures contracts was (0.166)%, while the simple average daily change in the NAV of US12NG over the same time period was (0.170)%. The average daily difference was (0.003)% (or (0.3) basis points, where 1 basis point equals 1/100 of 1%). As a percentage of the daily movement of the average price of the benchmark futures contracts, the average error in daily tracking by the NAV was (0.353)%, meaning that over this time period US12NG’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of USBO units to the public on June 2, 2010 to March 31, 2012, the simple average daily change in its benchmark futures contract was 0.136%, while the simple average daily change in the NAV of USBO over the same time period was 0.132%. The average daily difference was (0.004)% (or (0.4) basis points, where 1 basis point equals 1/100 of 1%). As a percentage of the daily movement of the benchmark futures contract, the average error in daily tracking by the NAV was (0.929)%, meaning that over this time period USBO’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of USCI units to the public on August 10, 2010 to March 31, 2012, the simple average daily change in the Commodity Index was 0.060%, while the simple average daily change in the NAV of USCI over the same time period was 0.055%. The average daily difference was (0.005)% (or (0.5) basis points, where 1 basis point equals 1/100 of 1%). As a percentage of the daily movement of the Commodity Index, the average error in daily tracking by the NAV (1.554)%, meaning that over this time period USCI’s tracking error was within the plus or minus 10% range established as its benchmark tracking goal.

Since the commencement of the offering of CPER units to the public on November 15, 2011 to March 31, 2012, the simple average daily charge in the Copper Index was 0.104%, while the simple average daily charge in the NAV of CPER over the same time period was 0.098%, the average daily difference was (0.006)% (or (0.6) basis points, where 1 basis point equals 1/100 of 1%). As a percentage of the daily movement of the Copper Index, the average error is daily tracking by the NAV was (2.937)%.

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The table below shows the relationship between the trading prices of the units of each of the Related Public Funds and the daily NAV of such fund, since inception through March 31, 2012. The first row shows the average amount of the variation between the fund’s closing market price and NAV, computed on a daily basis since inception, while the second and third rows depict the maximum daily amount of the end of day premiums and discounts to NAV since inception, on a percentage basis. The General Partner believes that maximum and minimum end of day premiums and discounts typically occur because trading in units continues on the NYSE Arca until 4:00 p.m. New York time while regular trading in the benchmark futures contract on the NYMEX ceases at 2:30 p.m. New York time and the value of the relevant benchmark futures contract, for purposes of determining its end of day NAV can be determined at that time. One known exception to this conclusion were the premiums on trading in USNG units that occurred between July 8, 2009 and September 28, 2009, when USNG suspended the issuance of Creation Baskets as a result of regulatory concerns relating to the size of USNG’s positions in the natural gas futures and cleared swap markets, and there was continued demand for such units and other similar natural gas futures linked investments in the market.

For more information on the performance of the Related Public Funds, see the Performance Tables below.

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Performance of the Related Public Funds

USHO

COMPOSITE PERFORMANCE DATA FOR USHO

Name of Commodity Pool: United States Heating Oil Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: April 9, 2008

Aggregate Subscriptions (from inception through March 31, 2012): $33,857,235

Total Net Assets as of March 31, 2012: $10,720,526

NAV per Unit as of March 31, 2012: $35.74

Worst Monthly Percentage Draw-down: Oct 2008 (28.63)%

Worst Peak-to-Valley Draw-down: Jun 08 — Feb 09 (69.17)%

Number of Unitholders (as of December 31, 2011): 2,256

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of Draw-down, please see text below “Composite Performance Data for USOF.”

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USNG:

COMPOSITE PERFORMANCE DATA FOR USNG

Name of Commodity Pool: United States Natural Gas Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: April 18, 2007

Aggregate Subscriptions (from inception through March 31, 2012): $14,248,635,601

Total Net Assets as of March 31, 2012: $777,630,034

NAV per Unit as of March 31, 2012: $16.01

Worst Monthly Percentage Draw-down: Jul 2008 (32.13)%

Worst Peak-to-Valley Draw-down: Jun 08 — March 12 (96.81)%

Number of Unitholders (as of December 31, 2011): 237,227

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of Draw-down, please see text below “Composite Performance Data for USOF.”

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US12OF:

COMPOSITE PERFORMANCE DATA FOR US12OF

Name of Commodity Pool: United States 12 Month Oil Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: December 6, 2007

Aggregate Subscriptions (from inception through March 31, 2012): $390,436,623

Total Net Assets as of March 31, 2012: $171,781,690

NAV per Unit as of March 31, 2012: $45.81

Worst Monthly Percentage Draw-down: Oct 2008 (29.59)%

Worst Peak-to-Valley Draw-down: June 08 — Feb 09 (66.97)%

Number of Unitholders (as of December 31, 2011): 14,016

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of Draw-down, please see text below “Composite Performance Data for USOF.”

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UGA:

COMPOSITE PERFORMANCE DATA FOR UGA

Name of Commodity Pool: United States Gasoline Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: February 26, 2008

Aggregate Subscriptions (from inception through March 31, 2012): $338,235,954

Total Net Assets as of March 31, 2012: $164,993,953

NAV per Unit as of March 31, 2012: $56.89

Worst Monthly Percentage Draw-down: Oct 2008 (38.48%)

Worst Peak-to-Valley Draw-down: June 08 — Dec 08 (69.02%)

Number of Unitholders (as of December 31, 2011): 26,024

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of Draw-down, please see text below “Composite Performance Data for USOF.”

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USSO:

COMPOSITE PERFORMANCE DATA FOR USSO

USSO Performance:

Name of Commodity Pool: United States Short Oil Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: September 24, 2009

Aggregate Subscriptions (from inception through March 31, 2012): $64,694,346

Total Net Assets as of March 31, 2012: $19,006,598

NAV per Unit as of March 31, 2012: $34.56

Worst Monthly Percentage Draw-down: Oct 2011 (16.00)%

Worst Peak-to-Valley Draw-down: Aug 10 — Feb 12 (33.97)%

Number of Unitholders (as of December 31, 2011): 3,288

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of draw-down, please see text below “Composite Performance Data for USOF.”

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US12NG:

COMPOSITE PERFORMANCE DATA FOR US12NG

Name of Commodity Pool: United States 12 Month Natural Gas Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: November 18, 2009

Aggregate Subscriptions (from inception through March 31, 2012): $97,441,469

Total Net Assets as of March 31, 2012: $28,649,446

NAV per Unit as of March 31, 2012: $16.37

Worst Monthly Percentage Draw-down: Mar 2010 (15.47)%

Worst Peak-to-Valley Draw-down: Dec 09 — March 12 (69.56)%

Number of Unitholders (as of December 31, 2011): 3,978

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of draw-down, please see text below “Composite Performance Data for USOF.”

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USBO:

COMPOSITE PERFORMANCE DATA FOR USBO

Name of Commodity Pool: United States Brent Oil Fund, LP

Type of Commodity Pool: Exchange traded security

Inception of Trading: June 2, 2010

Aggregate Subscriptions (from inception through March 31, 2012): $257,384,677

Total Net Assets as of March 31, 2012: $56,098,232

NAV per Unit as of March 31, 2012: $86.30

Worst Monthly Percentage Draw-down: Sept 2011 (9.85)%

Worst Peak-to-Valley Draw-down: April 11 — Sept 11 (17.27)%

Number of Unitholders (as of December 31, 2011): 7,959

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of draw-down, please see text below “Composite Performance Data for USOF.”

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USCI:

COMPOSITE PERFORMANCE DATA FOR USCI

Name of Commodity Pool: United States Commodity Index Fund

Type of Commodity Pool: Exchange traded security

Inception of Trading: August 10, 2010

Aggregate Subscriptions (from inception through March 31, 2012): $617,765,552

Total Net Assets as of March 31, 2012: $422,986,585

NAV per Unit as of March 31, 2012: $61.30

Worst Monthly Percentage Draw-down: Sept 2011 (11.69)%

Worst Peak-to-Valley Draw-down: April 11 — Sept 11 (18.43)%

Number of Unitholders (as of December 31, 2011): 33,783

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of draw-down, please see text below “Composite Performance Data for USOF.”

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CPER:

COMPOSITE PERFORMANCE DATA FOR CPER

Name of Commodity Pool: United States Copper Index Fund

Type of Commodity Pool: Exchange traded security

Inception of Trading: November 15, 2011

Aggregate Subscriptions (from inception through March 31, 2012): $2,500,000

Total Net Assets as of March 31, 2012: $2,708,051

NAV per Unit as of March 31, 2012: $27.08

Worst Monthly Percentage Draw-down: Dec 2011 (3.85)%

Worst Peak-to-Valley Draw-down: Nov 11 — Dec 11 (3.85)%

Number of Unitholders (as of December 31, 2011): 66

PAST PERFORMANCE IS NOT NECESSARILY INDICATIVE OF FUTURE RESULTS

For a definition of draw-down, please see the text below “Composite Performance Data for USOF.”

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