Currently, Bitcoin futures have very high margin requirements. The Cboe requires 40% of the notional amount for maintenance margin, the CME requires 43%. Your broker will likely require more than that. The culprit behind these high requirements is Bitcoin’s high volatility—until that calms down the exchanges will protect themselves by requiring a bunch of up-front money. If you don’t come up with the money for a margin call they want to close out your position without leaving a negative balance.

All other procedures set forth in the Authorized Participant Agreement must be followed in order to receive the next determined NAV. The requisite Fund Securities and the Balancing Amount (minus a redemption Transaction Fee or additional charges for requested cash redemptions) or the Cash Redemption Amount, as applicable and at the discretion of the Advisor, will be transferred by the second (2nd) NSCC Business Day following the date on which such request for redemption is deemed received. Cash-only redemption orders and Global Fund orders may not be placed through the Clearing Process.

the price of Bitcoin and Bitcoin Futures Contracts. In particular, it is possible that the price of the Bitcoin Futures Contracts subsequent to a “fork” may be linked to the price of bitcoin on only one of the resulting Bitcoin Networks, rather than the aggregate price of bitcoin on all resulting Bitcoin Networks. The CBOE Futures Exchange (“CFE”) and Chicago Mercantile Exchange (“CME”) have announced different protocols for addressing forks.

Changes in the laws of the United States and/or the Cayman Islands, under which the Parent Funds and the Subsidiaries are organized, respectively, could result in the inability of a Parent Fund and/or its respective Subsidiary to operate as described in this SAI and could negatively affect a Parent Fund and its shareholders. For example, the Cayman Islands does not currently impose any income, corporate or capital gains tax, estate duty, inheritance tax, gift tax or withholding tax on the Subsidiaries. If Cayman Islands law changes such that a Subsidiary must pay Cayman Islands taxes, Parent Fund shareholders would likely suffer decreased investment returns. See “Taxation” below for more information.

Each Fund may invest in real estate investment trusts (“REITs”). Equity REITs invest primarily in real property, while mortgage REITs invest in construction, development and long-term mortgage loans. Their value may be affected by changes in the value of the underlying property of the REIT, the creditworthiness of the issuer, property taxes, interest rates, and tax and regulatory requirements, such as those relating to the environment. REITs are dependent upon management skill, are not diversified and are subject to heavy cash flow dependency, default by borrowers, self-liquidation and the possibility of failing to qualify for tax-free pass-through of income under the Code and failing to maintain exempt status under the 1940 Act.

The Officers, under the supervision of the Board, manage the day-to-day operations of the Trust. One Trustee and all of the Officers of the Trust are directors, officers or employees of ProShare Advisors or Foreside Management Services, LLC. The other Trustees are Independent Trustees. The Trustees and some Officers are also directors and officers of some or all of the other funds in the Fund Complex. The Fund Complex includes all funds advised by ProShare Advisors and any funds that have an investment adviser that is an affiliated person of ProShare Advisors.
Each Fund intends to use, on a regular basis, leveraged investment techniques in pursuing its investment objective. Leverage exists when a Fund achieves the right to a return on a capital base that exceeds the Fund’s assets. Utilization of leverage involves special risks and should be considered to be speculative. Specifically, leverage creates the potential for greater gains to Fund shareholders during favorable market conditions and the risk of magnified losses during adverse market conditions. Leverage is likely to cause higher volatility of the NAVs of these Funds’ Shares. Leverage may also involve the creation of a liability that does not entail any interest costs or the creation of a liability that requires the Fund to pay interest which would decrease the Fund’s total return to shareholders. If these Funds achieve their investment objectives, during adverse market conditions, shareholders should experience a loss greater than they would have incurred had these Funds not been leveraged.
Leverage (All Funds, except the Matching ProShares Funds, 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 the Short (-1x) ProShares Funds and the CDS Short North American HY Credit ETF)
Source: MV Index Solutions GmbH (MVIS®). MVIS is a wholly owned subsidiary of Van Eck Associates Corporation. Data as of December 8, 2017 (synthesized data from BitMEX, OKCoin, CryptoFacilities, and BTCC which represents non-U.S. listed bitcoin futures trading on these exchanges). Not intended to be a forecast of future events, a guarantee of future results or investment advice. Current market conditions may not continue.  
Almost every crypto-list today starts off with the king – Bitcoin! Satoshi Nakamoto created Bitcoin a long time ago, and it was the first cryptocurrency to step blinking into the bright light of the world! Bitcoin has surpassed all expecatations and continues to grow in value and popularity – despite recent setbacks and a lot of FUD from trolls and haters (read: traditional banks) online.  Will Bitcoin continue to increase in value in 2018? Recent trends say: Yes! In my opinion, any cryptocurrency portfolio should hold some Bitcoin.
Two members of the Silk Road Task Force—a multi-agency federal task force that carried out the U.S. investigation of Silk Road—seized bitcoins for their own use in the course of the investigation.[86] DEA agent Carl Mark Force IV, who attempted to extort Silk Road founder Ross Ulbricht ("Dread Pirate Roberts"), pleaded guilty to money laundering, obstruction of justice, and extortion under color of official right, and was sentenced to 6.5 years in federal prison.[86] U.S. Secret Service agent Shaun Bridges pleaded guilty to crimes relating to his diversion of $800,000 worth of bitcoins to his personal account during the investigation, and also separately pleaded guilty to money laundering in connection with another cryptocurrency theft; he was sentenced to nearly eight years in federal prison.[87]

The most common way to trade in Bitcoin and other cryptocurrency derivatives today is through contract-for-difference (CFD) contracts. These CFD contracts are usually traded over the counter (OTC), meaning that they are not traded on exchanges but directly between participants. Due to the high volatility (exceeding 1.5-2x std from the mean) most of the OTC platforms do not provide leverage on bitcoin and other cryptos CFDs.
If an investor gets the timing of the oscillations right, they can make money at every point along the way, going long when the market goes up and short when it drops. However, it is also difficult to come across any reliable strategy that has thus far been able to predict which events influence the price of bitcoin to which extent. The initial calling off of the Segwit2x fork is a good example of that. Shortly after the news broke, the market appeared to be divided into two camps – those who saw less value because they would not receive the equivalent amount of their holdings in the new currency (“dividends”), and those who saw the news as a consolidation of bitcoin’s strength. The two camps pushed the price in opposite directions in a way that made it hard to predict which side would have the upper hand at which point in time.
With the increased use of technologies such as the Internet and the dependence on computer systems to perform necessary business functions, the Funds and the digital assets that underline the bitcoin futures contracts in which the Funds invest are susceptible to operational and information security risk. The digital nature of bitcoins and the irreversible nature of bitcoin transactions makes bitcoin an attractive target for theft, hacking and other cyber-attacks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber-attacks include, but are not limited to gaining unauthorized access to digital systems for purposes of misappropriating assets such as bitcoin or other cryptocurrencies or gaining access to sensitive information, corrupting data, or causing operational disruption. Cyber-attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites. Such events have historically correlated with a drop in the price of bitcoin, which may adversely affect your investment in a Fund. Cyber security failures or breaches of a Fund’s third party service provider (including, but not limited to, index providers, the administrator and transfer agent) or the issuers of the bitcoin futures contracts in which the Funds invest, have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, the inability of a Fund’s shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. The Funds their service providers, counterparties and other market participants on which the Funds rely could be negatively impacted as a result. While the Funds have established business continuity plans and systems to prevent such cyber-attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified.
Distributions of investment income are generally taxable to shareholders as ordinary income. Taxes on distributions of capital gains are determined by how long a Fund owned the investments that generated them, rather than how long a shareholder has owned his or her shares. In general, a Fund will recognize long-term capital gain or loss on investments it has owned for more than one year, and short-term capital gain or loss on investments it has owned for one year or less. Tax rules can alter a Fund’s holding period in investments and thereby affect the tax treatment of gain or loss on such investments. Distributions of net capital gain – the excess of net long-term capital gain over net short-term capital losses, in each case determined with reference to any loss carryforwards – that are properly reported by the Fund as capital gain dividends (“Capital Gain Dividends”) will be taxable to shareholders as long-term capital gains includible in net capital gain and taxable to individuals at reduced rates. Distributions of net short-term capital gain (as reduced by any net long-term capital loss for the taxable year) will be taxable to shareholders as ordinary income.
A Bitcoin (spot or futures) exchange (like any online trading firm) charges its clients a fee to carry out trading activities. As exchanges face the risk of hacking and theft, it is wise not to trust an exchange with all your coins. You should split and keep part of them in other devices or cold storage. Now with bitcoin futures being offered by some of the most prominent marketplaces, investors, traders and speculators are all bound to benefit. These centralized marketplaces will facilitate trade based on a trader’s outlook for bitcoin prices, gain exposure to bitcoin prices or hedge their existing bitcoin positions. Overall, the launching of bitcoin futures by Cboe and CME will facilitate price discovery and price transparency, enable risk-management via a regulated bitcoin product and give a further push to bitcoin as an accepted asset class. (For more, see: The Risks Of Buying Bitcoins.)

When a new crypto is launched, its founders announce how many coins will be mined. Once the quota is reached, no further coins can be produced. The first digital coin introduced was Bitcoin, which remains today the benchmark for all other digital coins. Among other currencies that have made their way into the cryptocurrency hall-of-fame we have: Ethereum, Ripple, Litecoin, EOS, and a number of derived currencies, including Bitcoin Cash and Bitcoin Gold.
and other factors. Thus, to the extent a Fund invests in swaps that use an ETF as the reference asset, that Fund may be subject to greater correlation risk and may not achieve as high a degree of correlation with its index as it would if the Fund used only swaps on the underlying index. The Advisor, under the supervision of the Board of Trustees, is responsible for determining and monitoring the liquidity of the Funds’ transactions in swap agreements.
If anything, the problem seems to start with incredibly lax risk management at this exchange.  According to the OKEX statement, the risk management team 'immediately' contacted the client to reduce the size of the trade - begging the question - how did their risk management system allow the trade to occur in the first place?  On the bright side, something like that should be easy to fix, but it is indicative, potentially of how many simple things are being overlooked in the rush to make money from crypto trading.
•   Interest Rate Risk — The Fund intends to invest a substantial portion of its assets in U.S. Treasury securities and is subject to interest rate risk. Interest rate risk is the risk that debt securities 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. A wide variety of factors can cause interest rates to rise (e.g., central bank monetary policies, inflation rates, general economic conditions, etc.). This risk may be elevated under current economic conditions because interest rates are at historically low levels. Returns on investment in debt instruments may trail the returns on other investment options, including investments in equity securities.
Do you remember, like, two weeks ago, when people were talking about how the launch of bitcoin futures at Cboe Global Markets Inc. and CME Group Inc. would allow for efficient short-selling of bitcoin and finally deflate the bubble? Smart hedge-fund money was lining up to bet against bitcoin, the thinking went, but had no convenient way to do it on the actual bitcoin exchanges. The only people trading bitcoin were the true believers, so of course it kept going up, but once it was opened up to normal financial players that would end. "The futures reduce the frictions of going short more than they do of going long, so it’s probably net bearish," said Craig Pirrong. 
Poloniex is popular with users seeking to convert cryptocurrencies, margin trade and lend. Services are accessible across the globe. Fees is dependent on the maker-the one whose name is already listed and taker-the one who makes an order. Makers are so named because they maintain the liquidity in the market. Every 24 hours the platform calculates the fees based on the volume traded between market and the taker for last 30 days and the fees is updated dynamically.
Trader A is a producer of pork bellies. In order to insure herself against a price drop in pork bellies in the future, she enters a futures contract with Trader B. Trader B uses these pork bellies to manufacture sliced breakfast bacon. Thus, he is not worried that prices might fall in the future – his worry is that prices will go up. Both traders agree that Trader A will sell a metric ton of pork bellies for 1,000 USD 3 months from now. This increases security for both of their businesses. Because a futures contract is a binding contract between two parties, neither party can drop out of the contract: Even if the price for pork bellies is 1,200 USD at the time of execution, trader A is still contractually obliged to sell for 1,000 USD.