This study provides new identification and estimation results for ascending (traditional English or online) auctions with unobserved auction‐level heterogeneity and an unknown number of bidders. When the seller's reserve price and two order statistics of bids are observed, we derive conditions...

This study provides new identification and estimation results for ascending (traditional English or online) auctions with unobserved auction-level heterogeneity and an unknown number of bidders. When the seller's reserve price and two order statistics of bids are observed, we derive conditions...

This paper proposes an approach to proving nonparametric identification for distributions of bidders’ values in asymmetric second-price auctions. I consider the case when bidders have independent private values and the only available data pertain to the winner’s identity and the transaction...