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Complementary Bidding and the Collusive Arrangement: Evidence from an Antitrust Investigation

Robert Clark et al.

American Economic Journal: Microeconomics2025https://doi.org/10.1257/mic.20210450article
AJG 3ABDC A*
Weight
0.48

Abstract

Clustered bids and a missing mass of nearly tied bids have both been proposed as markers of collusion. We present causal empirical evidence from an actual procurement cartel that bidding involves both clustering and a gap around the winning bid. We support these results with information from the testimony of cartel participants that explains how both patterns arise naturally as part of an arrangement featuring complementary bidding. Based on these findings, we develop an easy-to-implement screen for collusive arrangements featuring complementary bidding. (JEL D43, D44, H76, L12, L13, L74)

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https://doi.org/https://doi.org/10.1257/mic.20210450

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@article{robert2025,
  title        = {{Complementary Bidding and the Collusive Arrangement: Evidence from an Antitrust Investigation}},
  author       = {Robert Clark et al.},
  journal      = {American Economic Journal: Microeconomics},
  year         = {2025},
  doi          = {https://doi.org/https://doi.org/10.1257/mic.20210450},
}

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Complementary Bidding and the Collusive Arrangement: Evidence from an Antitrust Investigation

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Evidence weight

0.48

Balanced mode · F 0.40 / M 0.15 / V 0.05 / R 0.40

F · citation impact0.44 × 0.4 = 0.18
M · momentum0.55 × 0.15 = 0.08
V · venue signal0.50 × 0.05 = 0.03
R · text relevance †0.50 × 0.4 = 0.20

† Text relevance is estimated at 0.50 on the detail page — for your query’s actual relevance score, open this paper from a search result.