A Bitcoin futures contract is exactly what you would expect from the example above, replacing pork bellies with Bitcoin. It is a contract that enables you to buy Bitcoin at a predetermined price at a specific point in the future. For example, if today’s Bitcoin price is 8,000 USD per BTC and you expect it to rise to 10,000 USD per BTC in 4 weeks, then entering a contract which allows you to buy Bitcoin at 9,000 USD in 4 weeks is highly attractive.

In the event that a Fund invests in an Underlying RIC that is not publicly offered within the meaning of the Code, the Fund’s redemption of shares of such Underlying RIC may cause the Fund to be treated as receiving a dividend taxable as ordinary income on the full amount of the redemption instead of being treated as realizing capital gain (or loss) on the redemption of the shares of the Underlying RIC.

Given the economic and environmental concerns associated with mining, various "minerless" cryptocurrencies are undergoing active development.[40][41] Unlike conventional blockchains, some directed acyclic graph cryptocurrencies utilise a pay-it-forward system, whereby each account performs minimally heavy computations on two previous transactions to verify. Other cryptocurrencies like Nano utilise a block-lattice structure whereby each individual account has its own blockchain. With each account controlling its own transactions, no traditional proof-of-work mining is required, allowing for feeless, instantaneous transactions.[42][better source needed]
Portfolio managers are generally responsible for multiple investment company accounts. As described below, certain inherent conflicts of interest arise from the fact that a portfolio manager has responsibility for multiple accounts, including conflicts relating to the allocation of investment opportunities. Listed below for each portfolio manager are the number and type of accounts managed or overseen by such portfolio manager as of May 31, 2017.
All three DBRS rating categories for short term debt use “(high)”, “(middle)” and “(low)” as subset grades to designate the relative standing of the credit within a particular rating category. The following comments provide separate definitions for the three grades in the Prime Credit Quality area, as this is where ratings for active borrowers in Canada continue to be heavily concentrated.
•   Small-and Mid-Cap Company Investment Risk — The Fund may invest in stocks of small-and mid-cap companies. The risk of equity investing may be particularly acute for securities of issuers with smaller market capitalizations. Small-and mid-cap company stocks may trade at greater spreads or lower trading volumes, and may be less liquid than the stocks of larger companies. Small-and mid-cap companies may have limited product lines or resources, may be dependent upon a particular market niche and may have greater fluctuations in price than the stocks of larger companies. Further, stocks of small-and mid-sized companies could be more difficult to liquidate during market downturns compared to larger, more widely traded companies. In addition, small-and mid-cap companies may lack the financial and personnel resources to handle economic or industry-wide setbacks and, as a result, such setbacks could have a greater effect on small-and mid-cap security prices.
Each Fund may invest in a wide range of fixed income securities, which may include foreign sovereign, sub-sovereign and supranational bonds, as well as any other obligations of any rating or maturity such as foreign and domestic investment grade corporate debt securities and lower-rated corporate debt securities (commonly known as “junk bonds”). Lower-rated or high yield debt securities include corporate high yield debt securities, zero-coupon securities, payment-in-kind securities, and STRIPS. Investment grade corporate bonds are those rated BBB or better by Standard & Poor’s Rating Group (“S&P”) or Baa or better by Moody’s Investor Services (“Moody’s”). Securities rated BBB by S&P are considered investment grade, but Moody’s considers securities rated Baa to have speculative characteristics. See Appendix A for a description of corporate bond ratings. The Funds may also invest in unrated securities.
Certain U.S. government securities are issued or guaranteed by agencies or instrumentalities of the U.S. government including, but not limited to, obligations of U.S. government agencies or instrumentalities, such as the Federal National Mortgage Association (“Fannie Mae” or “FNMA”), the Government National Mortgage Association (“Ginnie Mae” or “GNMA”), the Small Business Administration, the Federal Farm Credit Administration, Federal Home Loan Banks, Banks for Cooperatives (including the Central Bank for Cooperatives), Federal Land Banks, Federal Intermediate Credit Banks, the Tennessee Valley Authority, the Export-Import Bank of the United States, the Commodity Credit Corporation, the Federal Financing Bank, the Student Loan Marketing Association, the National Credit Union Administration and the Federal Agricultural Mortgage Corporation. Some obligations issued or guaranteed by U.S. government agencies and instrumentalities, including, for example, GNMA pass-through certificates, are supported by the full faith and credit of the U.S. Treasury. Other obligations issued by or guaranteed by federal agencies, such as those securities issued by FNMA, are supported by the discretionary authority of the U.S. government to purchase certain obligations of the federal agency but are not backed by the full faith and credit of the U.S. government, while other obligations issued by or guaranteed by federal agencies, such as those of the Federal Home Loan Banks, are supported by the right of the issuer to borrow from the U.S. Treasury. While the U.S. government provides financial support to such U.S. government-sponsored federal agencies and instrumentalities described above, no assurance can be given that the U.S. government will always do so, since the U.S. government is not so obligated by law. U.S. Treasury notes and bonds typically pay coupon interest semi-annually and repay the principal at maturity. All U.S. government securities are subject to credit risk.

Market Price Variance Risk — Fund shares are listed for trading on the [                ] Exchange and can be bought and sold in the secondary market at market prices. The market price of shares will fluctuate in response to changes in the value of the Fund’s holdings, supply and demand for shares and other market factors. In addition, the securities held by the Fund may be traded in markets that close at a different time than the Exchange. Because the Fund generally values such securities as of its local market closing time, the daily net asset value (“NAV”) may vary from the market performance of the Fund as of the Exchange close (typically at [ ] p.m., Eastern Time). Furthermore, liquidity in such securities may be reduced after the applicable closing times. This may cause wider spreads and larger premium and discounts than would otherwise be the case if each market was open until the close of trading on the Exchange. ProShare Advisors cannot predict whether shares will trade above, below or at a price equal to the value of the Fund’s holdings. Given the fact that shares can be created and redeemed in Creation Units, as defined below, ProShare Advisors believes that large discounts or premiums to the value of the Fund’s holdings should not be sustained. The Fund’s investment results are measured based upon the daily NAV of the Fund.

The Board has determined that its leadership structure is appropriate in light of the characteristics of the Trust and each of the Funds. These characteristics include, among other things, the fact that all Funds are organized under one Trust; all Funds are exchange-traded funds; all Funds have common service providers; and that the majority of Funds are geared funds, with similar principal investment strategies. As a result, the Board addresses governance and management issues that are often common to all or most of the Funds. In light of these characteristics, the Board has determined that a four-member Board, including three Independent
Qualifying Income described in clause (i) of subparagraph (a) above) will be treated as Qualifying Income. In general, such entities will be treated as partnerships for federal income tax purposes because they meet the passive income requirement under Code section 7704(c)(2). In addition, although in general the passive loss rules of the Code do not apply to RICs, such rules do apply to a RIC with respect to items attributable to an interest in a qualified publicly traded partnership. Moreover, the amounts derived from investments in foreign currency will be treated as Qualifying Income for purposes of subparagraph (a) above. There is a remote possibility that the Internal Revenue Service (“IRS”) could issue guidance contrary to such treatment with respect to foreign currency gains that are not directly related to a RIC’s principal business of investing in stocks or securities (or options or futures with respect to stocks or securities), which could affect a Fund’s ability to meet the 90% gross income test and adversely affect the manner in which that Fund is managed.

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.