Methods and systems for establishing a reserve price for a publisher's ad space inventory offered via a real-time bidding market are disclosed. In some embodiments, a certain percentage of traffic (e.g., ad requests) received at an ad market server are redirected to one or more external networks, such as ad networks, for processing. The performance of the redirected ad requests is analyzed to determine an expected clearing price for the ad requests. The expected clearing price of a particular ad request corresponding to a particular ad space, if greater than a publisher-established reserve price, is used as a market reserve price when presenting the ad requests in a real-time bidding market.