Seldom are observed losing bids available in industry data. A special workshop of the Fed Cattle Market Simulator was designed to capture bids for each pen of cattle traded. Data enabled identifying buyer and seller behavior in the price discovery process, both before and after imposed mergers of the two largest and two smallest packer teams. Highest losing bids also were estimated with packer bid functions and compared with observed highest losing bids. An estimated price discovery model indicated market structure as measured by number of buyers was more important than simply the number of bids or size of transactions.