(1) A period at the opening and the close of some futures markets in which the price for each futures contract is established by auction; (2) Buyer's Call generally applies to cotton, also called "call sale." A purchase of a specified quantity of a specific grade of a commodity at a fixed number of points above or below a specified delivery month futures price with the buyer allowed a period of time to fix the price either by purchasing a future for the account of the seller or telling the seller when he wishes to fix the price; (3) Seller's Call, also called "call purchase," is the same as the buyer's call except that the seller has the right to determine the time to fix the price; (4) option contract giving the buyer the right but not the obligation to purchase the commodity or to enter into a long futures position; and (5) the requirement that a financial instrument be returned to the issuer prior to maturity, with principal and accrued interest paid off upon return.