To seek its investment objective, as a cash reserve, for liquidity purposes, or as “cover” for positions it has taken, each Fund may invest all or part of its assets in cash or cash equivalents, which include, but are not limited to, short-term money market instruments, U.S. government securities, floating and variable rate notes, commercial paper, certificates of deposit, time deposits, bankers’ acceptances or repurchase agreements and other short-term liquid instruments secured by U.S. government securities. Each Fund may invest in money market instruments issued by foreign and domestic governments, financial institutions, corporations and other entities in the U.S. or in any foreign country. Each Fund may also invest in pooled investment vehicles that invest in, and themselves qualify as, money market instruments.

Currently there are a several digital asset trading platforms that provide investors with forms of derivative products such as futures, so one could estimate and synthesize the discrete futures curve from the averages of various curves. MVIS research used BitMEX, OKCoin, CryptoFacilities, and BTCC as sources, to construct and approximate bitcoin futures curve based on non-U.S. bitcoin futures trading on these exchanges.
Furthermore, each Fund, except the Matching ProShares Funds, the Managed Futures Strategy ETF, the Crude Oil Strategy ETF, the CDS Short North American HY Credit ETF, the Bitcoin Futures Strategy ETF, the Short Bitcoin Futures Strategy ETF, the Blockchain/Bitcoin Strategy ETF, the Bitcoin Futures/Equity Strategy ETF has an investment objective to match the performance, a multiple (2x or 3x), the inverse (-1x) or a multiple of the inverse (-2x or -3x) of the performance of a benchmark on a single day. A “single day” is measured from the time the Fund calculates its NAV to the time of the Fund’s next NAV calculation. These Funds are subject to the correlation risks described above. In addition, while a close correlation of any Fund to its benchmark may be achieved on any single day, over time, the cumulative percentage increase or decrease in the NAV of the shares of a Fund may diverge, in some cases significantly, from the cumulative percentage decrease or increase in the benchmark due to a compounding effect as further described in the Prospectus and below.

Other countries are not as accommodative of bitcoin. For example, the Chinese government on December 3, 2013 issued a notice that classified bitcoin as legal and “virtual commodities;” however, the same notice restricted the banking and payment industries from using bitcoin, creating uncertainty and limiting the ability of Bitcoin Exchanges to operate in the then-second largest bitcoin market. Then on September 15, 2017, the Chinese government and local financial regulators officially requested some Chinese Bitcoin Exchanges and digital asset trading platforms to shut down by the end of September 2017. In addition, the Central Bank of Bolivia banned the use of bitcoin as a means of payment in May 2014. Further, in July 2016, the Russian Ministry of Finance indicated it supports a proposed law that bans bitcoin domestically but allows for its use as a foreign currency. In September 2017 the head of the Russian central bank stated that it is categorically against regulating cryptocurrencies as money, as a means by which payment can be made for goods and services, and against equating them with foreign currency. Most recently, South Korea’s Office for Government Policy Coordination released a wide variety of proposed regulations which range from the imposition of capital gains taxes on profits realized from cryptocurrency trading, to banning minors from registering on South Korean bitcoin exchanges, and even prohibiting financial institutions from investing in digital assets. These restrictive stances towards digital assets may reduce the rate of expansion of bitcoin use or even eliminate the use of bitcoin entirely in these geographies.
Bitcoin is pseudonymous rather than anonymous in that the cryptocurrency within a wallet is not tied to people, but rather to one or more specific keys (or "addresses").[53] Thereby, bitcoin owners are not identifiable, but all transactions are publicly available in the blockchain.[53] Still, cryptocurrency exchanges are often required by law to collect the personal information of their users.[53]
This post-effective amendment relates only to ProShares Bitcoin Futures Strategy ETF, ProShares Short Bitcoin Futures Strategy ETF, ProShares Bitcoin Futures/Equity Strategy ETF and ProShares Bitcoin/Blockchain Strategy ETF, each a new series of ProShares Trust. No information relating to any other series or class of series of ProShares Trust is amended or superseded hereby.
RD – Restricted default. ‘RD’ ratings indicate an issuer that in Fitch’s opinion has experienced an uncured payment default on a bond, loan or other material financial obligation but which has not entered into bankruptcy filings, administration, receivership, liquidation or other formal winding-up procedure, and which has not otherwise ceased operating. This would include:
•   Short Sale Exposure Risk — The Fund seeks inverse or “short” exposure through short positions in bitcoin futures contracts and other financial instruments. This will cause the Fund to be exposed to certain risks associated with selling assets short. These risks include, under certain market conditions, an increase in the volatility and decrease in the liquidity of the asset underlying the short position, which may lower the Fund’s return, result in a loss, have the effect of limiting the Fund’s ability to obtain inverse exposure through financial instruments such as swap agreements and futures contracts, or require the Fund to seek inverse exposure through alternative investment strategies that may be less desirable or more costly to implement. To the extent that, at any particular point in time, the assets underlying the short position may be thinly traded or have a limited market, including due to regulatory action, the Fund may be unable to meet its investment objective due to a lack of available securities or counterparties. During such periods, the Fund’s ability to issue additional Creation Units may be adversely affected. Obtaining inverse exposure through these instruments may be considered an aggressive investment technique. Inverse exposure must be actively managed in order to keep the Fund fully invested. See “Compounding Risk” above for an explanation of how this impacts performance
For instance, last year, an ETF was rejected. This resulted in the boost of altcoins. Here, Kelly says that we saw Bitcoin outperform and altcoins prices go flat. Cryptocurrencies such as Ethereum [ETH] and XRP [XRP] have been flat due to all the money flowing into Bitcoin. In case of an ETF rejection or even delay, a heavy amount of money will flow out of Bitcoin and into the others.
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.

•   A Fund’s income from or the proceeds of dispositions of its non-U.S. investments may be subject to withholding and other taxes imposed by foreign countries, which will reduce the Fund’s return on and taxable distributions in respect of its non-U.S. investments. Tax conventions between certain countries and the United States may reduce or eliminate these taxes. If more than 50% of the value of a Fund’s total assets at the close of a taxable year consists of securities of foreign corporations, the Fund will be eligible to elect to “pass through” to you foreign income taxes that it has paid. If this election is made, you will be required to include your share of those taxes in gross income as a distribution from the Fund and you generally will be allowed to claim a credit (or a deduction, if you itemize deductions) for these amounts on your federal U.S. income tax return, subject to certain limitations.
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.
The information in this Statement of Additional Information is not complete and may be changed. Shares of the Fund may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This Statement of Additional Information is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.
A dividend or Capital Gain Dividend with respect to shares of a Fund held by a tax-deferred or qualified plan, such as an IRA, retirement plan, or corporate pension or profit sharing plan, generally will not be taxable to the plan. Distributions from such plans will be taxable to individual participants under applicable tax rules without regard to the character of the income earned by the qualified plan. Shareholders should consult their tax advisors to determine the suitability of shares of a Fund as an investment through such plans and the precise effect of an investment on their particular situation.

Many institutional investors are wise to use the futures contracts to lower the Bitcoin price to buy in lower by setting the stop-loss triggers at support levels to push down the price further and further to make it look like a crash. This scares novice investors to support the bears and sell to avoid a total loss. By taking this strategy, the Wall Street investors are strategically pushing down the price for in order to re-enter at much lower levels and potentially set Bitcoin up for another rocket rise to unprecedented highs. Then, assumingly, collect profits and repeat the cycle, increasing profits each time Bitcoin rises and falls.

(c) distribute with respect to each taxable year at least 90% of the sum of its investment company taxable income (as that term is defined in the Code without regard to the deduction for dividends paid—generally, taxable ordinary income and the excess, if any, of net short-term capital gains over net long-term capital losses) and net tax-exempt interest income, for such year.
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.
R-1 (low) – Short term debt rated “R-1 (low)” is of good credit quality. The overall strength and outlook for key liquidity, debt and profitability ratios is not normally as favorable as with higher rating categories, but these considerations are still respectable. Any qualifying negative factors which exist are considered manageable, and the entity is normally of sufficient size to have some influence in its industry.

  •   Large-Cap Company Investment Risk —The Fund invests in stocks of large-cap companies. Although returns on investments in large-cap companies are often perceived as being less volatile than the returns of companies with smaller market capitalizations, the return on large-cap securities could trail the returns on investments in smaller and mid-sized companies for a number of reasons. For example, large-cap companies may be unable to respond quickly to new competitive challenges, such as changes in technology, and also may not be able to attain the high growth rate of successful smaller companies.
The tax rules are uncertain with respect to the treatment of income or gains arising in respect of commodity-linked exchange-traded notes (“ETNs”) and certain commodity-linked structured notes; also, the timing and character of income or gains arising from ETNs can be uncertain. An adverse determination or future guidance by the IRS (which determination or guidance could be retroactive) may affect a Fund’s ability to qualify for treatment as a regulated investment company and to avoid a Fund-level tax.
•   Active Management Risk — The performance of actively managed funds reflects, in part, the ability of ProShare Advisors to select investments and make investment decisions that are suited to achieving the Fund’s investment objective. ProShare Advisors’ judgments about the Fund’s investments may prove to be incorrect. If the investments selected and strategies employed by ProShare Advisors fail to produce the intended results, the Fund may not achieve its investment objective and could underperform other funds with a similar investment objective and/or strategies. The Fund does not seek to provide investment performance that would be opposite of a 30% investment in bitcoin futures contracts and a 70% investment in U.S. government securities.
Crypto Facilities and the CME Group  have been calculating and publishing the Bitcoin Reference Rate (BRR) since November 2016. Such an official rate is a prerequisite of options trading in the traditional markets. The BRR is calculated based on the rates from the biggest exchanges: Bitstamp, GDAX, itBit, and Kraken. More concretely, it is calculated based on all Bitcoin vs. USD trades on the participating exchanges between 3 and 4 p.m. London time. To calculate the BRR, the hour between 3 and 4 is divided into 12 intervals of 5 minutes. For each interval, the volume-weighted median of the Bitcoin price is calculated (statistically, the median, in contrast to the average, prevents single outliers from distorting the price). The BRR is then the average of these 12 median values. More details about the calculation of the BRR can be found in the BRR whitepaper.