Upon entering into a futures contract, each Fund will be required to deposit with the broker an amount of cash or cash equivalents in the range of approximately 5% to 10% of the contract amount for equity index futures and in the range of approximately 1% to 3% of the contract amount for treasury futures (these amounts are subject to change by the exchange on which the contract is traded). This amount, known as “initial margin,” is in the nature of a performance bond or good faith deposit on the contract and is returned to the Fund upon termination of the futures contract, assuming all contractual obligations have been satisfied. Subsequent payments, known as “variation margin,” to and from the broker will be made daily as the price of the index underlying the futures contract fluctuates, making the long and short positions in the futures contract more or less valuable, a process known as “marking-to-market.” At any time prior to expiration of a futures contract, a Fund may elect to close its position by taking an opposite position, which will operate to terminate the Fund’s existing position in the contract.
Collateralized mortgage obligations (“CMOs”) are debt obligations collateralized by mortgage loans or mortgage pass-through securities (collateral collectively hereinafter referred to as “Mortgage Assets”). Multi-class pass-through securities are interests in a trust composed of Mortgage Assets and all references in this section to CMOs include multi-class pass-through securities. Principal prepayments on the Mortgage Assets may cause the CMOs to be retired substantially earlier than their stated maturities or final distribution dates, resulting in a loss of all or part of the premium if any has been paid. Interest is paid or accrues on all classes of the CMOs on a monthly, quarterly or semi-annual basis. The principal and interest payments on the Mortgage Assets may be allocated among the various classes of CMOs in several ways. Typically, payments of principal, including any prepayments, on the underlying mortgages are applied to the classes in the order of their respective stated maturities or final distribution dates, so that no payment of principal is made on CMOs of a class until all CMOs of other classes having earlier stated maturities or final distribution dates have been paid in full.
A Fund will incur a loss as a result of a short sale if the price of the security increases between the date of the short sale and the date on which the Fund replaces the borrowed security. A Fund will realize a gain if the price of the security declines in price between those dates. The amount of any gain will be decreased, and the amount of any loss will be increased, by the amount of the premium, dividends or interest a Fund may be required to pay, if any, in connection with a short sale.
(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.

The Fund may invest 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.

Ann then goes on BFE and she wants to short on bitcoin at market price. She sees that only the January 9 contract has any orders. She could put a limit order in the orderbook if she wanted. However, she sees Bob's bid in the orderbook and decides to fill it, and uses her 0.2btc as margin to collateralize this position. She has just opened a position worth 1 bitcoin that has 5x leverage, and so has Bob.
There's a lot of ins and outs which can get confusing in arbitrage trading. We won't go into the technicals of why futures contracts trade at a premium to spot price. You can read a full explanation here. If it's not of interest to you, all you need to know is that there's a tendency, the further out in time the futures contract expires, for the premium to spot to be higher and higher in nominal percentage terms.