Cdel is retail, they are one of the largest. Almo
Post# of 148305
http://finra.complinet.com/en/display/display...nt_id=9989
5320. Prohibition Against Trading Ahead of Customer Orders
(a) Except as provided herein, a member that accepts and holds an order in an equity security from its own customer or a customer of another broker-dealer without immediately executing the order is prohibited from trading that security on the same side of the market for its own account at a price that would satisfy the customer order, unless it immediately thereafter executes the customer order up to the size and at the same or better price at which it traded for its own account.
(b) A member must have a written methodology in place governing the execution and priority of all pending orders that is consistent with the requirements of this Rule and Rule 5310. A member also must ensure that this methodology is consistently applied.