Having said that, bitcoin price action remains fraught with wild and inexplicable gaps, like a $400 drop and rise in an hour in the late hours of July 30, according to Bloomberg.  This particular trade, and unwind seems to have affected bitcoin pricing globally and likely impacted trading of the U.S. listed contracts as well.  Volumes and open interest seemed to have increased around the time of this large trade unwind.  It could be a coincidence, though I suspect that some smart traders, aware of the situation, put short trades on in these future contracts to take advantage of the forced unwind.
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.
I have worked with the CME in the past on product development (specifically CDS futures) and from my experience, they would not have missed anything this simple.  In fact, while I am not a huge fan of the concept of Bitcoin futures, as currently implemented, I do not expect any errors in the operation of the CME or CBOE futures contract.  I am sure that regulators will be questioning them on the back of the OKEX, as they should, and I am also quite positive the exchanges here will pass with flying colors.

This means simply that you put down 1 bitcoin and you can trade 20 on OKCoin, or 100 bitcoin on BitMEX. The multiple refers to the initial margin you need to open the nominal position value. You simply set the margin aside as collateral, and if the position goes against you, the collateral will be used to exit your position into a liquidation, or margin call.

The Board has appointed a chief compliance officer (“CCO”) for the Trust (who is also the Chief Compliance Officer for the Advisor). The CCO reports directly to the Board and participates in the Board’s meetings. The Independent Trustees meet at least annually in executive session with the CCO, and the Funds’ CCO prepares and presents an annual written compliance report to the Board. The CCO also provides updates to the Board on the operation of the Trust’s compliance policies and procedures and on how these procedures are designed to mitigate risk. Finally, the CCO and/or other officers or employees of the Advisor report to the Board in the event that any material risk issues arise.
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.
Note: This Prospectus provides general U.S. federal income tax information only. Your investment in the Fund may have other tax implications. If you are investing through a tax-deferred retirement account, such as an individual retirement account (IRA), special tax rules apply. Please consult your tax advisor for detailed information about a Fund’s tax consequences for you. See “Taxation” in the SAI for more information.

There are also purely technical elements to consider. For example, technological advancement in cryptocurrencies such as bitcoin result in high up-front costs to miners in the form of specialized hardware and software.[105] Cryptocurrency transactions are normally irreversible after a number of blocks confirm the transaction. Additionally, cryptocurrency can be permanently lost from local storage due to malware or data loss. This can also happen through the destruction of the physical media, effectively removing lost cryptocurrencies forever from their markets.[106]
reduce the amount of the Fund’s borrowings to the extent necessary to meet this 300% coverage requirement. Maintenance of this percentage limitation may result in the sale of portfolio securities at a time when investment considerations would not favor such sale. In addition to the foregoing, the Funds are authorized to borrow money as a temporary measure for extraordinary or emergency purposes in amounts not in excess of 5% of the value of each Fund’s total assets. This borrowing is not subject to the foregoing 300% asset coverage requirement. The Funds are authorized to pledge portfolio securities as ProShare Advisors deems appropriate in connection with any borrowings.
•   Subsidiary Investment Risk — Changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary are organized, respectively, could result in the inability of the Fund to operate as intended and could negatively affect the Fund and its shareholders. The Subsidiary is not registered under the 1940 Act and is not subject to all the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all the protections offered to investors in registered investment companies.
In pure financial theory, the value of a futures contract is based on a "no arbitrage condition" from the interest rates in each asset. We have Bitcoin and US Dollar. Bitcoin interest rates tend to be less than US Dollar interest rates, so when you want to replicate the future value of bitcoin in US dollars, you have to borrow USD at, say, 5%, and invest in Bitcoin at 1% return. This requires a premium on the futures exchange to be able to hedge that trade. 
Gains or losses attributable to fluctuations in exchange rates that occur between the time a Fund accrues income or other receivables or accrues expenses or other liabilities denominated in a foreign currency and the time the Fund actually collects such receivables or pays such liabilities generally are treated as ordinary income or ordinary loss. Similarly, on disposition of some investments, including debt securities and certain forward contracts denominated in a foreign currency, gains or losses attributable to
Cryptocurrencies allow traders to diversify their investment portfolio, as their price is mainly determined by demand and supply; Their value has a low correlation to national economies or political scenarios. Once Bitcoin surpassed the price of gold in 2017, US markets introduced 2 ETFs on Bitcoin and drew more and more institutional money into the world of cryptocurrencies. In 2017, Indian PM Narendra Modi has announced the gradual replacement of paper currency with electronic currency; In March 2018, the Marshall Islands announced that they would be introducing a cryptocurrency to replace US dollars as their main currency; other central banks are investigating the adoption of blockchain-like technologies… in short cryptocurrencies are probably here to stay. A growing number of crypto investors all over the world have already discovered the benefits:
One traditional attraction of trading futures is the ability to use relatively small amounts of money to potentially achieve outsized returns. In many futures markets the margin, the amount of money that your broker requires up-front before executing the trade can be quite small compared to the ultimate value of the contract. For example, as of 22-Dec-2017, each E-mini S&P 500 contract was worth $134K ($50*S&P 500 index value)—this “list price” of the contract is called its notional value.  The CME only requires you to maintain a minimum margin of $4.5K (3.4% of notional) to control this contract (brokers often require additional margin). Margin requirements this low are only possible because the volatility of the S&P 500 is well understood and your margin account balance is adjusted at the end of every trading day to account for the winnings or losses of the day. If your account balance falls below the margin minimum of $4.5K you’ll need to quickly add money to your account or your position will be summarily closed out by your broker. On the plus side, if you’ve predicted the S&P’s direction correctly your profits will be that same as if you completely owned the underlying stocks in the index. A +1% daily move in the S&P500 would yield $1340 in profit even though you only have $4500 invested— a 29% return—this multiplier effect is called leverage.

Created by Charlie Lee, a former Google engineer, Litecoin is an open-source payment network that operates on a global scale. It is not controlled by any centralized power, and it uses the “scrypt” as proof-of-work. It is similar to Bitcoin but has the advantage of offering a faster rate of generation and therefore faster transactions. This is one of the main reasons why its enthusiasts continue to invest or hold onto the coin even after finding out that its founder sold his stack.
On October 31, 2017, CME Group, the world's leading and most diverse derivatives marketplace, had announced its intent to launch bitcoin futures in the fourth quarter of 2017. “CME Group's Bitcoin futures will be available for trading on the CME Globex electronic trading platform, and for submission for clearing via CME ClearPort, effective on Sunday, December 17, 2017 for a trade date of December 18” as per CME’s officials statement.
Each of the Exchanges has established limitations governing the maximum number of call or put options on the same index which may be bought or written (sold) by a single investor, whether acting alone or in concert with others (regardless of whether such options are written on the same or different Exchanges or are held or written on one or more accounts or through one or more brokers). Under these limitations, option positions of all investment companies advised by the same investment adviser are combined for purposes of these limits. Pursuant to these limitations, an Exchange may order the liquidation of positions and may impose other sanctions or restrictions. These position limits may restrict the number of listed options which a Fund may buy or sell; however, the Advisor intends to comply with all limitations.
The Guidelines are maintained and implemented by ISS and are an extensive list of common proxy voting issues with recommended voting actions based on the overall goal of achieving maximum shareholder value and protection of shareholder interests. Generally, proxies are voted in accordance with the voting recommendations contained in the Guidelines. If necessary, the Advisor will be consulted by ISS on non-routine issues. Proxy issues identified in the Guidelines include but are not limited to:
Coinbase is not alone in making moves toward becoming an ATS. Recently, mobile payment app company Circle acquired Poloniex, another U.S.-based exchange, with plans to “clean up” the exchange. A slide that was initially leaked from a Circle presentation stated, “Circle has briefed the SEC on the transaction and indicated that upon closing that we will begin the process of registering the new entity with the SEC and FINRA as a Broker/Dealer and in turn as a licensed ATS…”
  •   Intellectual property rights claims may adversely affect the operation of the Bitcoin Network. Third parties may assert intellectual property rights claims relating to the operation of the Bitcoin Network. Regardless of the merit of any intellectual property or other legal action, any threatened action that reduces confidence in the Bitcoin Network’s long-term viability or the ability of end-users to hold and transfer bitcoin may adversely affect the price of bitcoin and adversely affect the price of the bitcoin futures contracts held by the Fund.
  •   Ownership of bitcoin is pseudonymous and the supply of accessible bitcoins is unknown. There is no registry showing which individuals or entities own bitcoin or the quantity of bitcoin that is owned by any particular person or entity. It is possible, that a small group of early bitcoin adopters hold a significant proportion of the bitcoin that has been thus far created. There are no regulations in place that would prevent a large holder of bitcoin from selling its bitcoins, which could depress the price of bitcoin and have an adverse effect on an investment in the Fund.
Note that you could just keep bitcoin on CryptoFacilities waiting to make the trade so you don't have to wait to move the bitcoin you bought over. This is called see-saw arbitrage model, where you keep funds on both exchanges to avoid having to wait. This is fine, but you can't ignore that there is extra capital being used in the play, so it affects your rate of return and capital utilisation. We will not use this method, we will do a full, complete, legitimate arbitrage process.