An imperfectly-informed regulator needs to procure multiple units of some good (e.g., green energy, market liquidity, pollution reduction, land conservation) that can be produced with heterogeneous technologies at various costs. How should she optimally procure these units? Should she run...

We study the mechanics of cartel enforcement and its interaction with bidding constraints in the context of repeated procurement auctions. Under collusion, bidding constraints weaken cartels by limiting the scope for punishment. This yields a test of collusive behavior exploiting the...