We study how seller exit and continuing sellers' behavior on eBay is affected by an improvement in market transparency. The improvement was achieved by reducing strategic bias in buyer ratings. It led to a significant increase in buyer valuation especially of sellers rated poorly prior to the change, but not to an increase in seller exit. When sellers had the choice between exiting-a reduction in adverse selection-and improved behavior-a reduction in moral hazard-, they preferred the latter because of lower cost. Increasing market transparency improves market outcomes.JEL classification: D47, D83, L15.