Abstract: The present invention is directed to a system for the electronic trading of financial instruments, and in particular, a system and method for the receipt, combination, and evaluation of equity portfolios for possible simultaneous execution by a sponsor at passively determined prices. In accordance with an embodiment of the present invention, a method for trading securities portfolios includes receiving a first intended portfolio trade having an associated specified commission, evaluating a combination of the first intended portfolio trade and a second intended portfolio trade for possible execution; and transmitting a decision on whether to execute the combination of the first intended portfolio trade and the second intended portfolio trade.