“…Hu, McAdams, and Shum (2013) extended these results to apply to settings with nonseparable unobserved auction‐level heterogeneity (where the number of potential bidders in An, Hu, and Shum (2010) can be considered a form of unobserved heterogeneity in their model) when three bids are observable in first price auctions. Additional work studying unobserved heterogeneity in first price auctions includes Armstrong (2013), Balat (2017), Seifert and Hüttel (2020), and Andreyanov and Caoui (2020). As explained above, existing deconvolution approaches (Li and Vuong (1998), Li, Perrigne, and Vuong (2000), Krasnokutskaya (2011)) have thus far been applied primarily in first price auctions (with a known number of bidders) where, unlike ascending auctions, independent bids are available.…”