A method for stock option trading includes receiving an option order at a
market, contemporaneously receiving a copy of the option order at an
electronic drop (EDrop) system, which is separate and distinct from the
market, obtaining a potential cross quantity and a potential cross price
based on the option order at the EDrop system, and submitting, through
the EDrop system, a contra-order, with respect to the option order, to
the market for fulfillment, wherein the contra-order specifies at least
one of an underlying security potential cross quantity, and the potential
cross price.