Start small. Get familiar with the platform you're using before you make any significant trades. BitMEX offers a sandbox using Testnet coins. OKCoin and BitVC do not offer a demo version, but you can start small with 1 contract and test how Open Long, Open Short, Close Long, Close Short and different order types work. If you contact CryptoFacilities you can also get access to a demo platform to use.
The Advisor may give consideration to placing portfolio transactions with those brokers and dealers that also furnish research and other execution related services to the Fund or the Advisor. Such services may include, but are not limited to, any one or more of the following: information as to the availability of securities for purchase or sale; statistical or factual information or opinions pertaining to investment; information about market conditions generally; equipment that facilitates and improves trade execution; and appraisals or evaluations of portfolio securities.

Although forward currency contracts may be used by the Funds to try to manage currency exchange risks, unanticipated changes in currency exchange rates could result in poorer performance than if a Fund had not entered into these transactions. Even if the Advisor correctly predicts currency exchange rate movements, a hedge could be unsuccessful if changes in the value of a Fund’s position do not correspond to changes in the value of the currency in which its investments are denominated. This lack of correlation between a Fund’s forwards and currency positions may be caused by differences between the futures and currency markets.

In general, the Code defines (1) “short-term capital gain dividends” as distributions of net short-term capital gains in excess of net long-term capital losses and (2) “interest-related dividends” as distributions from U.S. source interest income of types similar to those not subject to U.S. federal income tax if earned directly by an individual foreign shareholder, in each case to the extent such distributions are properly reported as such by a Fund in a written notice to shareholders.
Note that any losses on the bitcoin position is offset by the short position in the Jan XBT Futures contract.  Because Jan XBT was trading at a $1,000 premium to spot bitcoin, the profit for this trade is equal to that difference.  Now, keep in mind if bitcoin doubles between now and January 17 settlement the maximum profit is $1000.  Larry is giving up some upside to assure a return of $1000.
* The “Fund Complex” consists of all operational registered investment companies under the 1940 Act that are advised by ProShare Advisors LLC and any registered investment companies that have an investment adviser that is an affiliated person of ProShare Advisors LLC. Investment companies that are non-operational (and therefore, not publicly offered) as of the date of this SAI are excluded from these figures.
A mortgage-backed security is a type of pass-through security, which is a security representing pooled debt obligations repackaged as interests that pass income through an intermediary to investors. Each Fund may invest in mortgage-backed securities, as “cover” for the investment techniques these Funds employ. In the case of mortgage-backed securities, the ownership interest is in a pool of mortgage loans.

A Precautionary Note to Retail Investors — The Depository Trust Company (“DTC”), a limited trust company and securities depositary that serves as a national clearinghouse for the settlement of trades for its participating banks and broker-dealers, or its nominee will be the registered owner of all outstanding shares of the fund Your ownership of shares will be shown on the records of DTC and the DTC Participant broker through whom you hold the shares. PROSHARES TRUST WILL NOT HAVE ANY RECORD OF YOUR OWNERSHIP. Your account information will be maintained by your broker, who will provide you with account statements, confirmations of your purchases and sales of shares, and tax information. Your broker also will be responsible for furnishing certain cost basis information and ensuring that you receive shareholder reports and other communications from the Fund. Typically, you will receive other services only if your broker offers these services.
You may wonder: where do these contracts come from? We know on the spot market that bitcoins are being bought and sold for fiat, but how the heck are bitcoins being used to trade bitcoin futures contracts? Let's walk through a really simple example showing how an exchange functions when there's just a simple two traders who want to go long and short. 
If you want to speculate on the price of a cryptocurrency then the use of a Contract for Difference (CFD) is an option to consider. You won’t actually own the cryptocurrency, which means you don’t face the hassle and hurdles of trying to buy via one of the unregulated exchanges. Instead, a CFD is a financial instrument which allows you to speculate on price movements.
and the FTSE Developed Europe Index (the “Indices”) (ii) the figure at which an Index is said to stand at any particular time on any particular day or otherwise, or (iii) the suitability of the Index for the purpose to which it is being put in connection with the ProShares Ultra, Short and UltraShort FTSE China 50 and Ultra and UltraShort FTSE Developed Europe. None of the Licensor Parties have provided or will provide any financial or investment advice or recommendation in relation to the Index to ProShares or its clients. The Index is calculated by FTSE or its agent. None of the Licensor Parties shall be (a) liable (whether in negligence or otherwise) to any person for any error in the Index and (b) under any obligation to advise any person of any error therein.
Each Fund intends to invest in bitcoin futures contracts. The Funds will not invest directly in bitcoin and are not benchmarked to the current price of bitcoin. The value of the bitcoin futures contracts is generally based on the expected value of bitcoin at a future point in time, specifically, the expiration date of the bitcoin futures contracts. Other factors, such as cost of mining, storing and securing bitcoin may affect the value of bitcoin futures. A change in the price of bitcoin today (sometimes referred to as the “spot” price) will not necessarily result in a corresponding movement in the price of the bitcoin futures contracts since the price of the bitcoin futures contracts is based on expectations of the price of bitcoin at a future point in time. Additionally, there is no one centralized source for pricing bitcoin and pricing from one bitcoin exchange to the next can vary widely. Additionally, each Fund has the ability to invest in, or take a short position in, bitcoin futures contracts offered by CFE or CME, each of which uses a different exchange, or exchanges, to determine the value of bitcoin, which may lead to material differences in the value of the bitcoin futures contracts offered by CFE and CME. As a result, each Fund should be expected to perform very differently from the performance of the spot price of bitcoin (or the inverse of such performance) over all periods of time.
As discussed above in “Investment in a Subsidiary”, each of the Managed Futures Strategy ETF, the Crude Oil Strategy ETF the Bitcoin Futures Strategy ETF, the Short Bitcoin Futures Strategy ETF, the Blockchain/Bitcoin Strategy ETF, and the Bitcoin Futures/Equity Strategy ETF (each, a “Parent Fund”) intends to achieve commodity exposure through investment in a wholly-owned foreign subsidiary (each a “Subsidiary”). Each Subsidiary is classified as a corporation and is treated as a “controlled foreign corporation” (“CFC”) for U.S. federal income tax purposes. Each Parent Fund will limit its investments in its Subsidiary in the aggregate to 25% of the Parent Fund’s total assets. Each Parent Fund does not expect that income from its investment in its Subsidiary will be eligible to be treated as qualified dividend income or that distributions from its Subsidiary will be eligible for the corporate dividends-received deduction.
While the DJ Brookfield Global Infrastructure ETF and the Global Listed Private Equity ETF anticipate that, under normal market conditions, each Fund will invest primarily (i.e., at least 40% of its “assets” as defined above) in securities issued by issuers organized or located outside the United States (“foreign issuers”), to the extent that foreign issuers ever comprise less than 40% of such Fund’s assets for an extended period of time (i.e., six months), the Fund will take steps to: (i) either change its name; or (ii) change its benchmark.
Bitcoin (BTC) has been engaged in a predictable up and down pattern where it absolutely crashes at the beginning of any year and then sky-rockets as the year nears its end. Bitcoin held steady at around $19,000 in December 2017, and then sure enough – crashed big time to around $6,000 at the beginning of 2018. At the time of writing, March 8th 2018, the price of Bitcoin is relatively stable between $10,000 and $12,000. In my opinion, the price will run again soon.
  3. Make loans to other persons, except that the acquisition of bonds, debentures or other corporate debt securities and investment in government obligations, commercial paper, pass-through instruments, certificates of deposit, bankers’ acceptances and repurchase agreements and purchase and sale contracts and any similar instruments shall not be deemed to be the making of a loan, and except, further, that the Fund may lend its portfolio securities, provided that the lending of portfolio securities may be made only in accordance with applicable law and the guidelines set forth in the Prospectus and this SAI, as they may be amended from time to time.
Update 1st October 2018: The cryptocurrency market has been volatile as ever over the last 6 months. Unless you are a skilled trader, it is harder to make money in a bear market than in a bull market – and we have been in a bear market for some time now. Personally, I have stopped trading and I am now focussing on growing my portfolio passively using a cryptocurrency trading bot – you can find out more about this here.  If you are new to crypto, read on!
Distributions by the Fund to foreign shareholders other than Capital Gain Dividends, short-term capital gain dividends and interest-related dividends (e.g., dividends attributable to foreign-source dividend and interest income or to short-term capital gains or U.S. source interest income to which the exception from withholding described above does not apply) are generally subject to withholding of U.S. federal income tax at a rate of 30% (or lower applicable treaty rate).

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.
Assume it is January 3, 2015. Bob and Ann both want to trade at Bitcoin Futures Exchange (BFE). BFE offers 3 different contracts: one expiring and settling on Friday January 9 ('weekly'), another expiring Friday January 16th ('biweekly'), and finally one expiring in March 27 ('quarterly').  Each contract is worth 1 bitcoin notionally.  BFE has a policy that traders have to put 20% of margin down to enter a trade, so Bob and Ann deposit 0.2btc to their BFE accounts as they only want to trade 1 contract.
Individual shares of the Fund will be 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. ProShare Advisors cannot predict whether the Fund’s shares will trade above, below or at a price equal to the value of the Fund’s holdings. Differences between secondary market prices and NAV, the value of the Fund’s holdings, may be due largely to supply and demand forces in the secondary market, which may not be the same forces as those influencing prices for securities or financial instruments held by the Fund at a particular time. Given the fact that the Fund’s shares can be created and redeemed in Creation Units, ProShare Advisors believes that large discounts or premiums to the value of the Fund’s holdings should not be sustained.
On May 7, 2014, the SEC published an investor alert that highlighted fraud and other concerns relating to certain investment opportunities denominated in bitcoin and fraudulent and unregistered investment schemes targeted at participants in online bitcoin forums. On July 25, 2017, the SEC issued a Report of Investigation or Report which concluded that digital assets or tokens issued for the purpose of raising funds may be securities within the meaning of the federal securities laws. The Report emphasized that whether a digital asset is a security is based on the particular facts and circumstances, including the economic realities of the transactions. This was reiterated in a December 11, 2017 Public Statement emphasizing the risks of investing in digital assets such as bitcoin and noting the possibility that bitcoin and other digital assets may be deemed to be securities. The SEC continues to take action against persons or entities misusing bitcoin in connection with fraudulent schemes (i.e., Ponzi scheme), inaccurate and inadequate publicly disseminated information, and the offering of unregistered securities.

Investment in mortgage-backed securities poses several risks, including among others, prepayment, market and credit risk. Prepayment risk reflects the risk that borrowers may prepay their mortgages faster than expected, thereby affecting the investment’s average life and perhaps its yield. Whether or not a mortgage loan is prepaid is almost entirely controlled by the borrower. Borrowers are most likely to exercise prepayment options at the time when it is least advantageous to investors, generally prepaying mortgages as interest rates fall, and slowing payments as interest rates rise. Besides the effect of prevailing interest rates, the rate of prepayment and refinancing of mortgages may also be affected by appreciation in home values, ease of the refinancing process and local economic conditions. Market risk reflects the risk that the price of a security may fluctuate over time. The price of mortgage-backed securities may be particularly sensitive to prevailing interest rates, the length of time the security is expected to be outstanding, and the liquidity of the issue. In a period of unstable interest rates, there may be decreased demand for certain types of mortgage-backed securities, and each Fund invested in such securities wishing to sell them may find it difficult to find a buyer, which may in turn decrease the price at which they may be sold. Credit risk reflects the risk that a Fund may not receive all or part of its principal because the issuer or credit enhancer has defaulted on its obligations. Obligations issued by U.S. government-related entities are guaranteed as to the payment of principal and interest, but are not backed by the full faith and credit of the U.S. government. The performance of private label mortgage-backed securities, issued by private institutions, is based on the financial health of those institutions. With respect to GNMA certificates, although GNMA guarantees timely payment even if homeowners delay or default, tracking the “pass-through” payments may, at times, be difficult.
The global regulatory landscape for bitcoin and other digital assets has been inconsistent and continues to evolve. Some countries have taken an accommodating approach to the regulation of digital assets while others have banned their use. There are various accommodative approaches a country may take. Sweden and Australia treat bitcoin as a currency, while Canada and Taiwan have labeled bitcoin as a digital or virtual currency, distinct from fiat currency. Norway categorizes bitcoin as a form of virtual asset or commodity. The United Kingdom treats bitcoin as private money and determined that the value added tax will not apply to bitcoin sales, but it can be charged on the commission instead. In April 2017, legislation took effect in Japan that treats bitcoin and other digital assets as included in the definition of currency. In July 2016, the European Commission released a draft directive that proposed applying counter-terrorism and anti-money laundering regulations to virtual currencies, and, in September 2016, the European Banking authority advised the European Commission to institute new regulation specific to virtual currencies, with amendments to existing regulation as a stopgap measure. Regulatory bodies in some countries such as India and Switzerland have declined to exercise regulatory authority when afforded the opportunity.
Decentralized cryptocurrency is produced by the entire cryptocurrency system collectively, at a rate which is defined when the system is created and which is publicly known. In centralized banking and economic systems such as the Federal Reserve System, corporate boards or governments control the supply of currency by printing units of fiat money or demanding additions to digital banking ledgers. In case of decentralized cryptocurrency, companies or governments cannot produce new units, and have not so far provided backing for other firms, banks or corporate entities which hold asset value measured in it. The underlying technical system upon which decentralized cryptocurrencies are based was created by the group or individual known as Satoshi Nakamoto.[28]
These are fundraising mechanisms for newly launched cryptocurrencies. Investors in ICOs receive tokens in the new venture. Investors have poured billions of dollars into more than 1,000 ICOs over the past year. While many ICOs are legitimate, the vast majority have no real business plans or technology behind them. Many get launched with nothing more than a whitepaper by individuals with no technology or industry experience.
Still elsewhere, the Commodity Futures Trading Commission, in a footnote, quoted me saying "Just because you mumble the word 'blockchain' doesn't make otherwise illegal things legal," which I hope is now an official CFTC position. And here is Tyler Cowen on bitcoin volatility and Siegel's paradox: "Volatility is a feature of Bitcoin, not a bug, and that is in part for reasons that have nothing to do with speculation or bubbliness, but rather follow from the contours of the utility function." And: "No, a Guy Didn't Scam $1 Million by Selling Chuck E. Cheese Tokens as Bitcoins."
It is important to note, however, that leverage means that your potential losses may also be much higher. If pork belly prices fall, call options lose value in a much higher proportion than the pork bellies themselves. In the above example, if the price of pork bellies falls from 1,000 to 900 USD (by 10%), the price of call options may fall from 10.5 USD to almost zero, resulting in a near-total loss of your funds instead of a small loss of just 10%.