Patent ID: 7617139

Claim:
A computer system for facilitating transactions between a first party and a second party, the computer system comprising: an electronic memory device; and an electronic processor in communication with the memory device, wherein the memory device comprises instructions that when executed by the processor cause the processor to: receive an indication of a derivative portfolio indicating one or more securities on which the first party is long and the second party is short; receive an indication of a long portfolio of securities on which the second party holds a long position, wherein the long portfolio and the derivative portfolio do not have any securities in common; determine whether a right to substitute securities from the derivative portfolio resides with the first party or the second party; conditioned on the right to substitute residing with the first party, substitute a first security from the derivative portfolio for an equal value of a second security in response to an instruction originated by the first party; conditioned on the right to substitute residing with the second party, substitute a third security from the derivative portfolio for an equal value of a fourth security in response to an instruction originated by the second party.