One of the biggest issues for institutional investors is the fragmented nature of the market, requiring them to operate on several exchanges. Often, this forces them to come up with customized ways to deal with the limitations of each exchange — a time-consuming and frustrating exercise. Not only that, but this can lead to liquidity and slippage problems, as even small trades can consume liquidity and cause prices to slip.
To seek to achieve 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, certificates of deposit, bankers acceptances, or repurchase agreements secured by U.S. government securities.
Maintenance Margin - this is the % of the position value you have to have in your account at the very minimum to avoid being Margin Called.  In some exchanges, margin call will mean you get notified and must deposit more margin to avoid liquidation (like CryptoFacilities). On other exchanges you will at this point be liquidated out of your position. So if maintenance margin is 5%, then the 0.05 BTC of your initial margin will need to be kept for the position to be alive.
The first timestamping scheme invented was the proof-of-work scheme. The most widely used proof-of-work schemes are based on SHA-256 and scrypt.[18] The latter now dominates over the world of cryptocurrencies, with at least 480 confirmed implementations.[37] Some other hashing algorithms that are used for proof-of-work include CryptoNight, Blake, SHA-3, and X11.
Sub or Substratum is another open-source network with a huge focus on decentralizing the web and on “making the internet a free and fair place for the entire world.” This platform allows content creators to freely host their websites or applications on Substratum host, without any censorship blocks. Network users can then “run” Sub nodes and help the content get forwarded to end web users, who can access all Sub content in regular web browsers without any blocks or limits in shape of censorship.
  •   Risks Associated with Bitcoin – The Fund is exposed to risks associated with bitcoin. Investing in or gaining exposure to Bitcoin may provide the Fund with increased risk. Various global factors may negatively impact the Fund’s performance including legal, regulatory, political, social, regional and economic events. These risks, which could have a negative impact on the performance of the Fund and the trading price of Fund shares, include the following:
Investors purchasing and selling shares in the secondary market may not experience investment results consistent with those experienced by Authorized Participants creating and redeeming directly with the Fund. To the extent that exchange specialists, market makers, Authorized Participants, or other participants are unavailable or unable to trade the Fund’s shares and/or create or redeem Creation Units, trading spreads and the resulting premium or discount on the Fund’s shares may widen and the Fund’s shares may possibly be subject to trading halts and/or delisting.

Given the economic and environmental concerns associated with mining, various "minerless" cryptocurrencies are undergoing active development.[40][41] Unlike conventional blockchains, some directed acyclic graph cryptocurrencies utilise a pay-it-forward system, whereby each account performs minimally heavy computations on two previous transactions to verify. Other cryptocurrencies like Nano utilise a block-lattice structure whereby each individual account has its own blockchain. With each account controlling its own transactions, no traditional proof-of-work mining is required, allowing for feeless, instantaneous transactions.[42][better source needed]

•   Market Price Variance Risk — Fund shares are 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 shares will trade above, below or at a price equal to the value of the Fund’s holdings. Given the fact that shares can be created and redeemed in Creation Units, as defined below, ProShare Advisors believes that large discounts or premiums to the value of the Fund’s holdings should not be sustained. The Fund’s investment results are measured based upon the daily NAV of the Fund. Investors purchasing and selling shares in the secondary market may not experience investment results consistent with those experienced by Authorized Participants creating and redeeming directly with the Fund. To the extent that exchange specialists, market makers, Authorized Participants, or other participants are unavailable or unable to trade the Fund’s shares and/or create or redeem Creation Units, trading spreads and the resulting premium or discount on the Fund’s shares may widen and the Fund’s shares may possibly be subject to trading halts and/or delisting.
THIS MATERIAL HAS BEEN PREPARED BY A FUTURESONLINE BROKER WHO PROVIDES RESEARCH MARKET COMMENTARY AND TRADE RECOMMENDATIONS AS PART OF HIS OR HER SOLICITATION FOR ACCOUNTS AND SOLICITATION FOR TRADES. FUTURESONLINE, ITS PRINCIPALS, BROKERS AND EMPLOYEES MAY TRADE IN DERIVATIVES FOR THEIR OWN ACCOUNTS OR FOR THE ACCOUNTS OF OTHERS. DUE TO VARIOUS FACTORS (SUCH AS RISK TOLERANCE, MARGIN REQUIREMENTS, TRADING OBJECTIVES, SHORT TERM VS. LONG TERM STRATEGIES, TECHNICAL VS. FUNDAMENTAL MARKET ANALYSIS, AND OTHER FACTORS) SUCH TRADING MAY RESULT IN THE INITIATION OR LIQUIDATION OF POSITIONS THAT ARE DIFFERENT FROM OR CONTRARY TO THE OPINIONS AND RECOMMENDATIONS CONTAINED THEREIN.
When a Fund purchases a put or call option on a futures contract, the Fund pays a premium for the right to sell or purchase the underlying futures contract for a specified price upon exercise at any time during the option period. By writing (selling) a put or call option on a futures contract, a Fund receives a premium in return for granting to the purchaser of the option the right to sell to or buy from the Fund the underlying futures contract for a specified price upon exercise at any time during the option period.
!! WARNING !!! Note that on CryptoFacilities each contract is denominated by 1 BTC. So if you bought a fraction of BTC you can NOT perform a perfect hedge of the value. If you round the BTC you bought with start capital down, you will have slight overexposure LONG with the left-over BTC. If you round up and short an extra contract, you will have slight overexposure SHORT.
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