An ad publisher like eBay has multiple ad sources to serve ads from. Specifically, for eBay's text ads, there are two ad sources, viz. eBay Commerce Network (ECN) and Google. The problem and solution we have formulated considers two ad sources. However, the solution can be extended for any number of ad sources. A study was done on performance of ECN and Google ad sources with respect to the revenue per mille (RPM, or revenue per thousand impressions) ad queries they bring while serving ads. It was found that ECN performs better for some ad queries and Google performs better for others. Thus, our problem is to optimally allocate ad traffic between the two ad sources to maximize RPM.