This paper examines the optimal choices of two competing auction houses, where each one can choose its auction date, so that the auctions run either simultaneously, sequentially or with an overlap. We use the art market as an application. Under plausible outcome assumptions, we show that if the auctions are running as a one-time-only event, then the optimal strategy of both is to run simultaneous auctions. In the more realistic scenario, where auctions are running as recurrent events, overlapping auctions turn out to be equilibrium choices. If the process of supply of objects to the auction house is taken into account, then overlapping auctions in the version of almost simultaneously running auctions will be the equilibrium outcome of the optimizing behavior of the auction houses.

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