Abstract: A method allocates quantities of an underlying financial product for a plurality of orders, each being for a quantity of a derivative financial product counter to a previously received order for the derivative financial product and characterized by a ratio of the quantity of the derivative financial product to a quantity of the underlying financial product, and includes receiving first and second orders for quantities of the derivative financial product, computing first and second quantities of the underlying financial product, based on the first and second orders to achieve the ratio, rounding the first quantity to determine a first whole number quantity, generating a composite quantity of the underlying financial product based on the first and second quantities, generating a rounded representation of the composite quantity, and determining a second whole number quantity of the underlying financial product based on the rounded representation and the first whole number quantity.

Abstract: In an Exchange which assigns only a whole number/integer representation of a computed number of futures contracts to a covered order for one or more option contracts, a method allocates quantities of an underlying financial product in connection with a plurality of orders, each being for a quantity of a derivative financial product derived from the underlying financial product and each being counter to a previously received order for a quantity of the derivative financial product, the previously received order being further characterized by a specified ratio of the quantity of the derivative financial product thereof to a quantity of the underlying financial product.

Abstract: Systems and methods for determining implied spreads are provided. An example includes receiving a new order for a financial instrument and determining if the new order in combination with pending orders creates an implied spread. The implied spread may be submitted with information to facilitate matching the legs of the implied spread using the new order. The detection of the implied spread may be performed outside of a match engine; thus, permitting the detection to occur in parallel and apart from the operation of the match engine.