Short Term USD Emerging Markets Bond ETF; Inflation Expectations ETF; CDS Short North American HY Credit ETF; Crude Oil Strategy 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 ETF or Ultra High Yield ETF) in order to receive that day’s closing NAV per Share
If you want to do scalping, then shorter-term expiree contracts that settle really soon would be fine. Keep in mind, the normal state of futures markets is "contango", which means that longer dated contracts will have a premium to the current spot rate, to reflect the interest rate differential and time preference.  This means you will see Weeklies maybe with a $1-2 preium and Quarterlies (assuming they expire months from now) with a $5-8 premium.  As an example we have Quarterlies contracts right now at OKCoin that settle on December 25. So we're just starting December now, that means that even though these are "Quarterlies" contracts by classification, they are expiring not 3 months from now, but 1 month from now. Don't mix up the settlement expiration date with the naming convention. 
  •   The bitcoin exchanges on which bitcoin trades are relatively new and, in most cases, largely unregulated and, therefore, may be more exposed to 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.
Bitcoin (BTC) has been engaged in a predictable up and down pattern where it absolutely crashes at the beginning of any year and then sky-rockets as the year nears its end. Bitcoin held steady at around $19,000 in December 2017, and then sure enough – crashed big time to around $6,000 at the beginning of 2018. At the time of writing, March 8th 2018, the price of Bitcoin is relatively stable between $10,000 and $12,000. In my opinion, the price will run again soon.

Several factors may affect a Fund’s ability to achieve a high degree of correlation with its benchmark. Among these factors are: (i) a Fund’s fees and expenses, including brokerage (which may be increased by high portfolio turnover) and the costs associated with the use of derivatives; (ii) less than all of the securities underlying a Fund’s benchmark being held by the Fund and/or securities not included in its benchmark being held by a Fund; (iii) an imperfect correlation between the performance of instruments held by a Fund, such as futures contracts, and the performance of the underlying securities in a benchmark; (iv) bid-ask spreads (the effect of which may be increased by portfolio turnover); (v) holding instruments traded in a market that has become illiquid or disrupted; (vi) a Fund’s share prices being rounded to the nearest cent; (vii) changes to the benchmark that are not disseminated in advance; (viii) the need to conform a Fund’s portfolio holdings to comply with investment restrictions or policies or regulatory or tax law requirements;

Bitcoin and other cryptocurrencies have evolved from a playful experiment among technical experts to an established and growing branch of the global financial industry. This means that the times in which cryptocurrency traders and investors only concerned themselves with straightforward buying and selling are over. Derivatives are now entering the picture.