Margin Call - when you run out of bitcoin on your account to cover the contract positions you have taken (your account value doesn't cover the Maintance Margin) you are officially rekt. Some exchanges like CryptoFacilities will merely notify you that you have to deposit more or reduce your positions to increase your margin. Others like BitMEX will liquidate you at this level where the exchange takes over your position to liquidate it into the market to prevent system loss.
Non-VanEck proprietary information contained herein has been obtained from sources believed to be reliable, but not guaranteed. Not intended to be a forecast of future events, a guarantee of future results or investment advice. Historical performance is not indicative of future results. Current data may differ from data quoted. No part of this material may be reproduced in any form, or referred to in any other publication, without express written permission of VanEck.

•   Counterparty Risk —The Fund bears the risk that the counterparty to derivative transaction, such as a futures contract, defaults or otherwise fails to honor its obligations. If a counterparty defaults, the Fund will lose money and the value of an investment in the Fund may decrease. The Fund may engage in futures transactions with a limited number of counterparties, which may increase the Fund’s exposure to counterparty risk. The effect of the volatility of bitcoin pricing or other aspects of trading in bitcoin futures on futures clearinghouses for bitcoin futures is currently unknown, and may result in increased counterparty risk.
COVERED BONDS. The Funds may invest in covered bonds, which are debt securities issued by banks or other credit institutions that are backed by both the issuing institution and underlying pool of assets that compose the bond (a “cover pool”). The cover pool for a covered bond is typically composed of residential or commercial mortgage loans or loans to public sector institutions. A covered bond may lose value if the credit rating of the issuing bank or credit institution is downgraded or the quality of the assets in the cover pool deteriorates.
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.
In addition, the Advisor, any of its affiliates or employees and the Funds have a policy not to enter into any agreement or other understanding—whether written or oral—under which brokerage transactions or remuneration are directed to a broker to pay for distribution of a Fund’s shares. The table below sets forth the brokerage commissions paid by each Fund for the period noted for each Fund. Because each of the New Funds was not operational at the end of the Trust’s last fiscal year, information on brokerage commissions paid by the Fund is not included in this SAI.
On top of that, the cryptocurrency market travels at lightspeed compared to other markets. New coins enter the market on a daily basis (in 2016, there were about 550 different coins, today there are about 1,500), and each one has news every day. I’m not doubting your ability to consume and analyze news, but that level of information bombardment will always be more effectively consumed as a group. In these communities, you’ll see members link news and relevant articles about coins you’ve invested in and coins you’ve never heard of. The community will definitely expand your knowledge much faster than doing it all yourself.

The Funds may enter into forward contracts to attempt to gain exposure to an index or asset without actually purchasing such asset, or to hedge a position. Forward contracts are two-party contracts pursuant to which one party agrees to pay the counterparty a fixed price for an agreed-upon amount of an underlying asset or the cash value of the underlying asset at an agreed-upon date. When required by law, a Fund will segregate liquid assets in an amount equal to the value of the Fund’s total assets committed to the consummation of such forward contracts. Obligations under forward contracts so covered will not be considered senior securities for purposes of a Fund’s investment restriction concerning senior securities. Forward contracts that cannot be terminated in the ordinary course of business within seven days at approximately the amount at which a Fund has valued the asset may be considered to be illiquid for purposes of the Fund’s illiquid investment limitations. A Fund will not enter into a forward contract unless the Advisor believes that the other party to the transaction is creditworthy. The counterparty to any forward contract will typically be a major, global financial institution. A Fund bears the risk of loss of the amount expected to be received under a forward contract in the event of the default or bankruptcy of a counterparty. If such a default occurs, a Fund will have contractual remedies pursuant to the forward contract, but such remedies may be subject to bankruptcy and insolvency laws, which could affect the Fund’s rights as a creditor. 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 may each invest in forward contracts where commodities are the underlying asset.

•   Foreign Investments Risk — Investing in securities of foreign issuers may provide the Fund with increased risk. Various factors related to foreign investments may negatively impact the Fund’s performance, such as: i) fluctuations in the value of the applicable foreign currency; ii) differences in securities settlement practices; iii) uncertainty associated with evidence of ownership of investments in countries that lack centralized custodial services; iv) possible regulation of, or other limitations on, investments by U.S. investors in foreign investments; v) potentially higher brokerage commissions; vi) the possibility that a foreign government may withhold portions of interest and dividends at the source; vii) taxation of income earned in foreign countries or other foreign taxes imposed; viii) foreign exchange controls, which may include suspension of the ability to transfer currency from a foreign country; ix) less publicly available information about foreign issuers; x) changes in the denomination currency of a foreign investment; and xi) less certain legal systems in which the Fund might encounter difficulties or be unable to pursue legal remedies. Foreign investments also may be more susceptible to political, social, economic and regional factors than might be the case with U.S. securities. In addition, markets for foreign investments are usually less liquid, more volatile and significantly smaller than markets for U.S. securities, which may affect, among other things, the Fund’s ability to purchase or sell foreign investments at appropriate times. Because of differences in settlement times and/or foreign market holidays, transactions in a foreign market may take place one or more days after the necessary exposure to these investments is determined. Until the transactions are effected, the Fund is exposed to increased foreign currency risk and market risk.

The policy for each Fund regarding purchases and sales of securities is that primary consideration will be given to obtaining the most favorable prices and efficient executions of transactions. Consistent with this policy, when securities transactions are effected on a stock exchange, the policy is to pay commissions that are considered fair and reasonable without necessarily determining that the lowest possible commissions are paid in all circumstances. The Advisor believes that a requirement always to seek the lowest possible commission cost could impede effective portfolio management and preclude the Fund and the Advisor from obtaining a high quality of brokerage and execution services. In seeking to determine the reasonableness of brokerage commissions paid in any transaction, the Advisor relies upon its experience and knowledge regarding commissions generally charged by various brokers and on its judgment in evaluating the brokerage and execution services received from the broker. Such determinations are necessarily subjective and imprecise, as in most cases an exact dollar value for those services is not ascertainable. In addition to commission rates, when selecting a broker for a particular transaction, the Advisor considers but is not limited to the following efficiency factors: the broker’s availability, willingness to commit capital, reputation and integrity, facilities reliability, access to research, execution capacity and responsiveness.
Short Term USD Emerging Markets Bond ETF; Crude Oil Strategy ETF; Inflation Expectations ETF; CDS Short North American HY Credit ETF and Short or Ultra Fixed Income ProShares Funds    2:30 p.m. (3:00 p.m., if transmitted by mail; except 4:00 p.m., if transmitted by mail on behalf of Short High Yield or Ultra High Yield) in order to receive that day’s closing NAV per Share
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. 
ProShare Advisors, pursuant to a separate Management Services Agreement, performs certain administrative services on behalf of the Funds, such as negotiating, coordinating and implementing the Trust’s contractual obligations with the Funds’ service providers; monitoring, overseeing and reviewing the performance of such service providers to ensure adherence to applicable contractual obligations; and preparing or coordinating reports and presentations to the Board of Trustees with respect to such service providers as requested or as deemed necessary. For these services, the Trust pays to ProShare Advisors a fee at the annual rate of 0.10% of average daily net assets for each of the Funds. ProShare Advisors has entered into an Advisory and Management Services Fee Waiver Agreement that waives this management services fee for the Morningstar Alternatives Solution ETF through at least October 31, 2018. Prior to this date, ProShare Advisors may not terminate the arrangement without the approval of the Board.
You could imagine the spread going the other way, though. If everyone really was clamoring to short bitcoin, and if the futures offered a more convenient way to do it than the bitcoin exchanges, then you'd expect the short sellers to pay a premium to short via futures. Instead of selling a bitcoin at $18,000 today, they'd be willing to sell a synthetic bitcoin for $17,500, paying the spread to an arbitrageur who was willing to do the actual shorting for them. But the fact that the spread is mostly positive, and that bitcoin's price has been mostly going up, suggests that the demand has mostly been for synthetic long positions, not short.

EDIT: #10 Bonus (Suggested by @kerstenwirth ) — always check the ticker symbol. Ticker symbols are not universal, and may vary from exchange to exchange in rare cases. Those cases, though, can come back to bite you. For example, Bitcoin Cash trades on some exchanges as BCH, while it trades on others as BCC. BCC is also the ticker symbol for BitConnect, which was recently outted as a Ponzi Scheme. If you bought BCC under the impression was Bitcoin Cash, you would’ve lost a lot of money.

  •   The bitcoin exchanges on which bitcoin trades are relatively new and, in most cases, largely unregulated and, therefore, may be more exposed to volatility, fraud and security breaches than established, regulated exchanges for other products. Over the past several years, a number of Bitcoin Exchanges have been closed due to fraud, failure, security breaches or governmental regulations. The nature of the assets held at Bitcoin Exchanges make them appealing targets for hackers and a number of Bitcoin Exchanges have been victims of cybercrimes. No Bitcoin Exchange is immune from these risks. Fraudulent activity can increase volatility and have an adverse effect on the price of bitcoin, the general acceptance of bitcoin as an investment or means of currency and could have a negative impact on the bitcoin futures contracts in which the Fund invests and the value of the Fund.

There are many groups on Facebook where you can find likeminded folks who will happily talk crypto all day but the problem is that 99% of these groups are filled with people who have only a very basic understanding of cryptocurrency and the knowledge available here is not particularly strong. I have recently left almost every single group on Facebook as, in my opinion, they are largely filled with FUD.
A Fund’s current obligations under most swap agreements (total return swaps, equity/index swaps, interest rate swaps) will be accrued daily (offset against any amounts owed to the Fund) and any accrued but unpaid net amounts owed to a swap counterparty will be covered by segregating or earmarking cash or other assets determined to be liquid, but typically no payments will be made until the settlement date. In connection with CDS in which a Fund is a “buyer”, the Fund will segregate or earmark cash or assets determined to be liquid by the Advisor, with a value at least equal to the Fund’s maximum potential exposure under the swap (e.g., any accrued but unpaid net amounts owed by the Fund to any clearinghouse counterparty). In connection with CDS in which a Fund is a “seller”, however, the Fund will segregate or earmark cash or assets determined to be liquid by the Advisor, with a value at least equal to the full notional amount of the swap (minus any variation margin or amounts owed to the Fund under an offsetting cleared transaction). This segregation or earmarking is intended to ensure that a Fund has assets available to satisfy its potential obligations with respect to the transaction. Each Fund reserves the right to modify its asset segregation policies in the future, including modifications to comply with any changes in the positions articulated by the SEC or its staff regarding asset segregation. Swap agreements that cannot be terminated in the ordinary course of business within seven days at approximately the amount a Fund has valued the asset may be considered to be illiquid for purposes of the Fund’s illiquid investment limitations.
In general, a foreign corporation that is not engaged in and is not treated as engaged in a U.S. trade or business is nonetheless subject to tax at a flat rate of 30% (or lower tax treaty rate), generally payable through withholding, on the gross amount of certain U.S.-source income that is not effectively connected with a U.S. trade or business. There is presently no tax treaty in force between the United States and the jurisdiction in which any Subsidiary is (or would be) resident that would reduce this rate of withholding tax. Income subject to such a flat tax is of a fixed or determinable annual or periodic nature and includes dividends and interest income. Certain types of income are specifically exempted from the 30% tax and thus withholding is not required on payments of such income to a foreign corporation. The 30% tax generally does not apply to capital gains (whether long-term or short-term) or to interest paid to a foreign corporation on its deposits with U.S. banks. The 30% tax also does not apply to interest which qualifies as “portfolio interest.” Very generally, the term portfolio interest includes U.S.-source interest (including OID) on an obligation in registered form, and with respect to which the person, who would otherwise be required to deduct and withhold the 30% tax, received the required statement that the beneficial owner of the obligation is not a U.S. person within the meaning of the Code.
Consistent with a client’s investment objective, the Advisor may enter into guarantee close agreements with certain brokers. In all such cases, the agreement calls for the execution price at least to match the closing price of the security. In some cases, depending upon the circumstances, the broker may obtain a price that is better than the closing price and which under the agreement provides additional benefits to clients. The Advisor will generally distribute such benefits pro rata to applicable client trades.
Fundamental securities analysis is not used by ProShare Advisors in seeking to correlate a Matching Fund’s investment returns with its index. Rather, ProShare Advisors primarily uses a passive or mathematical approach to determine the investments a Matching Fund makes and techniques it employs. While ProShare Advisors attempts to minimize any “tracking error,” certain factors tend to cause a Matching Fund’s investment results to vary from a perfect correlation to its index, as applicable. See “Special Considerations” below for additional details.
through direct investments/short positions in the securities and/or through investments with similar economic characteristics. For the purposes of each such investment policy, “assets” includes a Fund’s net assets, as well as amounts borrowed for investment purposes, if any. In addition, for purposes of such an investment policy, “assets” includes not only the amount of a Fund’s net assets attributable to investments providing direct investment exposure to the type of investments suggested by its name (e.g., the value of stocks, or the value of derivative instruments such as futures, options or options on futures), but also cash and cash equivalents that are segregated on the Fund’s books and records or being used as collateral, as required by applicable regulatory guidance, or otherwise available to cover such investment exposure. The Board has adopted a policy to provide investors with at least 60 days’ notice prior to changes in a Fund’s name policy.
Well since then bitcoin is up more than 50 percent; it reached a record of $19,511 early Monday, hours after CME launched its futures contract. "Bitcoin Climbs as Futures Debut Fails to Incite Attack by Shorts," is the Bloomberg headline about Sunday's start of trading on CME. On the other hand, bitcoin was actually down a bit on the first full day of CME trading yesterday, and fell further overnight; "Bitcoin Futures Prices Fall in CME Debut" is the Wall Street Journal headline about Monday's trading. It is of course still very early days for the futures, and it's still possible that the shorts will come in and drive the price down. I guess it's even possible bitcoin bulls and bears will both flock to the futures market and trade with each other to find an efficient and stable price that reflects bitcoin's fundamental value, whatever that is.

In June 2015, the New York Department of Financial Services (the “NYDFS”) finalized a rule that requires most businesses involved in digital currency business activity in or involving New York, excluding merchants and consumers, to apply for a license (“BitLicense”) from the NYDFS and to comply with anti-money laundering, cyber security, consumer protection, and financial and reporting requirements, among others. As an alternative to the BitLicense in New York, firms can apply for a charter to become limited purpose trust companies qualified to engage in digital currency business activity. Other states have considered regimes similar to the BitLicense, or have required digital currency businesses to register with their states as money transmitters, such as Washington and Georgia, which results in digital currency businesses being subject to requirements similar to those of NYDFS’ BitLicense regime. Certain state regulators, such as the Texas Department of Banking, Kansas Office of the State Bank Commissioner and the Illinois Department of Financial and Professional Regulation, have found that mere transmission of bitcoin, without activities involving transmission of fiat currency, does not constitute money transmission requiring licensure. The North Carolina Commissioner of Banks has issued guidance providing that North Carolina’s money transmission regulations only apply to the transmission of digital currency and not its use. In June 2014, the State of California adopted legislation that would formally repeal laws that could be interpreted as making illegal the use of bitcoin or other digital assets as a means of payment. In July 2017, Delaware amended its General Corporation Law to provide for the creation maintenance of certain required records by blockchain technology and permit its use for electronic transmission of stockholder communications.
BB, B, CCC, CC, and C – Obligations rated ‘BB’, ‘B’, ‘CCC’, ‘CC’, and ‘C’ are regarded as having significant speculative characteristics. ‘BB’ indicates the least degree of speculation and ‘C’ the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposures to adverse conditions.
Transaction fees payable to the Trust are imposed to compensate the Trust for the transfer and other transaction costs of a Fund associated with the issuance and redemption of Creation Units of Shares. A fixed Transaction Fee is applicable to each creation or redemption transaction, regardless of the number of Creation Units purchased or redeemed. In addition, a variable Transaction Fee equal to a percentage of the value of each Creation Unit purchased or redeemed may be applicable to a creation or redemption transaction. Purchasers of Creation Units of the Matching and Ultra ProShares Funds for cash may also be required to pay an additional charge to compensate the relevant Fund for brokerage, market impact or other expenses. Where the Trust permits an in-kind purchaser to substitute cash in lieu of depositing a portion of the Deposit Securities, the purchaser will be assessed an additional charge for cash purchases. The maximum Transaction Fee on purchases and redemptions will be 2.00% of the NAV of any Creation Unit, except that for the High Yield—Interest Rate Hedged, the Investment Grade—Interest Rate Hedged and the Short Term USD Emerging Markets Bond ETF, a Transaction Fee up to 3.00% will be charged on the cash used in lieu of depositing all or a portion of the Deposit Securities or the cash portion of any redemption transaction. The Transaction Fees charged to each Fund are presented in the Authorized Participant Handbook.
Under normal market conditions, each Fund intends to invest substantially all of its assets in Benchmark Futures Contracts. The contractual obligations of a buyer or seller holding a futures contract to expiration may be satisfied by settling in cash as designated in the contract specifications. Alternatively, futures contracts may be closed out prior to expiration by making an offsetting sale or purchase of an identical futures contract on the same or linked exchange before the designated date of settlement. Once this date is reached, the futures contract “expires.” The Funds do not intend to hold bitcoin futures contracts through expiration, but instead to “roll” their respective positions. “Rolling” refers to a process whereby futures contracts nearing expiration are closed out and replaced with an identical futures contract with a later expiration date. Accordingly, the Funds are subjects to risks related to rolling.
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 the ProShares Cayman Portfolio I, the ProShares Cayman Crude Oil Portfolio, the ProShares Cayman Bitcoin Futures Strategy Portfolio the ProShares Cayman Short Bitcoin Futures Strategy Portfolio, the ProShares Cayman Bitcoin Futures/Equity Strategy Portfolio and the ProShares Cayman Bitcoin/Blockchain Strategy Portfolio respectively, each a wholly-owned subsidiary of its respective Parent Fund (each, a “Subsidiary”) organized under the laws of the Cayman Islands. Each Parent Fund’s investment in its respective Subsidiary is intended to provide such Parent Fund with exposure to commodity and financial markets in accordance with applicable rules and regulations. Each Subsidiary may invest in derivatives, including futures, forwards, option and swap contracts, notes and other investments intended to serve as margin or collateral or otherwise support the Subsidiary’s derivatives positions. Neither Subsidiary is registered under the 1940 Act, and neither Subsidiary will have all of the protections offered to investors in RICs. The Board, however, has oversight responsibility for the investment activities of each Parent Fund, including its investment in its respective Subsidiary, and the Parent Fund’s role as the sole shareholder of the Subsidiary.
If a beneficial owner of Fund Shares who or which is a foreign shareholder has a trade or business in the United States, and income from the Fund is effectively connected with the conduct by the beneficial owner of that trade or business, such income will be subject to U.S. federal net income taxation at regular income tax rates and, in the case of a foreign corporation, may also be subject to a branch profits tax.
These developments are expected to not only further rally the price of Bitcoin, but also open the doors for more traditional investment opportunities based on cryptocurrencies, such as a Bitcoin exchange-traded fund (ETF). ETFs are currently very popular investment products for beginning and advanced investors because they charge low fees and usually have low volatility. Because high volatility is one of the factors preventing conventional investors from entering the crypto market, products such as these could offer them the best of both worlds.