Abstract: Systems, methods, and computer-readable storage media are provided for altering clearing price logic at auction time. Configurable parameters included in the clearing price logic make the logic configurable at run time based upon one or more of an ad size, the identity of the pages on which ads are presented, the content of the pages on which ads are presented, a targeting segment of which a user or browser ID is a member, or any combination thereof. This enables experimentation in the exchange and optimization of the logic without requiring alterations in the code and ensures that the price paid is at least equivalent to the minimum bid that would have been needed to win the auction.