In a futures market, if the price is $500/BTC, an investor needs to buy 50 futures contracts, each worth $10. If an investor wishes to open a positive position then he goes long with “buy" contracts, and if he decides to open a negative position, he goes short with “sell” contracts. An investor’s position can be either positive or negative for the same instrument. (For more, see: Bitcoin Mass Hysteria: The Disaster that Brought Down Mt. Gox.)
the option to purchase the asset underlying the option at the exercise price if the option is exercised. During the term of the option, the writer may be assigned an exercise notice by the broker-dealer through whom the option was sold. The exercise notice would require the writer to deliver, in the case of a call, or take delivery of, in the case of a put, the underlying asset against payment of the exercise price. This obligation terminates upon expiration of the option, or at such earlier time that the writer effects a closing purchase transaction by purchasing an option covering the same underlying asset and having the same exercise price and expiration date as the one previously sold. Once an option has been exercised, the writer may not execute a closing purchase transaction. To secure the obligation to deliver the underlying asset in the case of a call option, the writer of a call option is required to deposit in escrow the underlying asset or other assets in accordance with the rules of the Options Clearing Corporation (the “OCC”), an institution created to interpose itself between buyers and sellers of options. The OCC assumes the other side of every purchase and sale transaction on an exchange and, by doing so, gives its guarantee to the transaction. When writing call options on an asset, a Fund may cover its position by owning the underlying asset on which the option is written. Alternatively, the Fund may cover its position by owning a call option on the underlying asset, on a share-for-share basis, which is deliverable under the option contract at a price no higher than the exercise price of the call option written by the Fund or, if higher, by owning such call option and depositing and segregating cash or liquid instruments equal in value to the difference between the two exercise prices. In addition, a Fund may cover its position by segregating cash or liquid instruments equal in value to the exercise price of the call option written by the Fund. When a Fund writes a put option, the Fund will segregate with its custodian bank cash or liquid instruments having a value equal to the exercise value of the option. The principal reason for a Fund to write call options on assets held by the Fund is to attempt to realize, through the receipt of premiums, a greater return than would be realized on the underlying assets alone.
Commodity Swaps. Commodity swaps are used either as substitutes for owning a specific physical commodities or as a means of obtaining non-leveraged exposure in markets where a specific commodity is not available. Commodity swaps provide the Fund with the additional flexibility of gaining exposure to commodities by using the most cost-effective vehicle available.
That's why liquidity and volume are essential to a quality exchange. If you enter that contract at $400 and you see bitcoin spot price jumping to $500 but nobody is trading futures so you can't sell it to them, you get screwed. Luckily at this point in 2016 there are numerous options for trading futures that are liquid and settle on short time horizons. So you can typically trade contracts and get in and out of them with decent spreads and reasonable fees.
Certain Funds expect to invest in exchange-traded funds, including exchange-traded funds registered under the 1940 Act (“Underlying ETFs”). Some such Underlying ETFs will be treated as regulated investment companies for federal income tax purposes (each such Underlying ETF, an “Underlying RIC”). In such cases, a Fund’s income and gains will normally consist, in whole or part, of dividends and other distributions from the Underlying RICs and gains and losses on the disposition of shares of the Underlying RICs. The amount of income and capital gains realized by a Fund and in turn a Fund’s shareholders in respect of the Fund’s investments in Underlying RICs may be greater than such amounts would have been had the Fund invested directly in the investments held by the Underlying RICs, rather than in the shares of the Underlying RICs. Similarly, the character of such income and gains (e.g., long-term capital gain, eligibility for the dividends-received deduction, etc.) will not necessarily be the same as it would have been had the Fund invested directly in the investments held by the Underlying RICs.
•   Any distributions from income or short-term capital gains that you receive generally are taxable to you as ordinary dividends for federal income tax purposes. Ordinary dividends you receive that a Fund reports as “qualified dividend income” may be taxed at the same rates as long-term capital gains, but will not be considered long-term capital gains for other federal income tax purposes, including the calculation of net capital losses.
As a shareholder on a Fund record date, you will earn a share of the investment income and net realized capital gains, if any, derived from a Fund’s direct security holdings and derivative instruments. You will receive such earnings as either an income dividend or a capital gains distribution. Each Fund intends to declare and distribute to its shareholders at least annually its net investment income, if any, as well as net realized capital gains, if any. Subject to Board approval, some or all of any net realized capital gains distribution may be declared payable in either additional shares of the respective Fund or in cash.
The Distribution and Service Plan is intended to permit the financing of a broad array of distribution-related activities and services, as well as shareholder services, for the benefit of investors. These activities and services are intended to make the Shares an attractive investment alternative, which may lead to increased assets, increased investment opportunities and diversification, and reduced per share operating expenses. There are currently no plans to impose distribution fees.

A Parent Fund’s recognition of any subpart F income from an investment in its Subsidiary will increase the Fund’s tax basis in such subsidiary. Distributions by a Subsidiary to a Parent Fund, including in redemption of its Subsidiary’s shares, will be tax free, to the extent of its Subsidiary’s previously undistributed subpart F income, and will correspondingly reduce the Fund’s tax basis in its Subsidiary, and any distributions in excess of the Fund’s tax basis in its Subsidiary will be treated as realized gain. Any losses with respect to the Fund’s shares of its Subsidiary will not be currently recognized. Subpart F income is generally treated as ordinary income, regardless of the character of a Subsidiary’s underlying income.

The Board is currently composed of four Trustees, including three Independent Trustees who are not “interested persons” of the Funds, as that term is defined in the 1940 Act (each an “Independent Trustee”). In addition to four regularly scheduled meetings per year, the Board holds executive sessions (with and without employees of the Advisor), special meetings, and/or informal conference calls relating to specific matters that may require discussion or action prior to its next regular meeting. The Independent Trustees have retained “independent legal counsel” as the term is defined in the 1940 Act.

Interest Rate Swaps. Interest rate swaps, in their most basic form, involve the exchange by a Fund with another party of their respective commitments to pay or receive interest. For example, a Fund might exchange its right to receive certain floating rate payments in exchange for another party’s right to receive fixed rate payments. Interest rate swaps can take a variety of other forms, such as agreements to pay the net differences between two different interest indexes or rates, even if the parties do not own the underlying instruments. Despite their differences in form, the function of interest rate swaps is generally the same: to increase or decrease a Fund’s exposure to long- or short-term interest rates. For example, a Fund may enter into a swap transaction to preserve a return or spread on a particular investment or a portion of its portfolio or to protect against any increase in the price of securities the Fund anticipates purchasing at a later date.
The ProShares Bitcoin/Blockchain Strategy ETF contains portfolio investments that are primarily listed on foreign markets. To the extent the Fund’s portfolio investments trade in foreign markets on days when the Fund is not open for business or when the primary exchange for its shares is not open, the value of the Fund’s assets may vary on days when shareholders may not be able to purchase or sell Fund shares and Authorized Participants may not be able to create or redeem Creation Units. Also, certain portfolio investments may not be traded on days the Fund is open for business.
There's a lot of ins and outs which can get confusing in arbitrage trading. We won't go into the technicals of why futures contracts trade at a premium to spot price. You can read a full explanation here. If it's not of interest to you, all you need to know is that there's a tendency, the further out in time the futures contract expires, for the premium to spot to be higher and higher in nominal percentage terms.