The SEC has approved a proposal from the C2 Options Exchange to make changes to the Automated Improvement Mechanism, or "AIM."   C2’s AIM allows a Participant to cross an agency order it presents as agent ("Agency Order") against principal interest or a solicited order, provided that it first exposes the Agency Order to a one-second auction. If the Agency Order is 50 contracts or greater, the Participant ("Initiating Participant") must stop the Agency Order at the NBBO, or the order’s limit price, if better.  For an Agency Order that is fewer than 50 contracts, the Participant must stop the Agency Order at the NBBO improved by 1 minimum increment, or the order’s limit price, if better). When initiating an auction, an Initiating Participant submitting an Agency Order to the AIM either must indicate a single price at which it seeks to cross the Agency Order ("single price submission") or must indicate that it will match as principal the price and size of all AIM responses ("auto-match").  Once submitted for processing, such submission may not be modified or cancelled.  A Request for Responses (“RFR”) will then be sent to any Participant that has elected to receive such requests, and the exposure period will last for one second. For further details, go to:  [C2 Options Exchange Rule Filing 11-043, 3/9/12].