Alpha Exchange yesterday published proposed public interest rule amendments intended to bring IntraSpread functionality in compliance with UMIR dark liquidity provisions that are coming into force on October 15, 2012. Specifically, the amendments would amend its IntraSpread dark pool functionality to remove dark orders that provide price improvement of 10% over the national best bid and offer, and introduce dark orders that can trade at the NBBO with SDL orders (orders with "fill or kill" duration that execute actively against dark orders) under certain circumstances.

The amendments are intended to come into effect on October 15, 2012. Comments are being accepted on the proposed amendments until August 27.