Revenue Non-monotonicity in Matching Markets

2026-02-24

AI Summary

This study challenges the conventional wisdom that revenue non-monotonicity in the Vickrey–Clarke–Groves (VCG) mechanism stems solely from complementarities among goods. The authors demonstrate that even in two-sided matching markets devoid of complementarities, an increase in buyers’ valuations can lead to a decrease in total revenue under the VCG mechanism. By leveraging mechanism design theory and matching market models, they construct a counterexample that rigorously establishes, for the first time, the presence of revenue non-monotonicity in pure matching environments. This result isolates the phenomenon from the confounding effects of complementarities, thereby revealing its prevalence across a broader class of market structures. The findings deepen the understanding of auction mechanism behavior and provide new theoretical foundations for the design of incentive-compatible mechanisms.

Technology Category

• Game Theory and Economic Paradigms: Mechanism Design
• Multiagent Systems: Mechanism Design
• Knowledge Representation and Reasoning: Nonmonotonic Reasoning

Application Category

• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• Security and Privacy: Large-scale security measurements
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems

Abstract

The Vickrey-Clarke-Groves (VCG) mechanism is infamously revenue non-monotone in combinatorial auctions. I.e., when a buyer increases their value for a bundle of items, the total auction revenue may decrease. Combinatorial auctions exhibit complementarities which broadly result in complexities in auction theory. This brief note shows that non-monotonicity in multi-item auctions is not a result of complementarities, and in fact, VCG is revenue non-monotone even in matching markets.

Problem

• Revenue Non-monotonicity
• VCG Mechanism
• Matching Markets
• Combinatorial Auctions
• Auction Theory

Innovation

• VCG mechanism
• revenue non-monotonicity
• matching markets
• combinatorial auctions
• auction theory