Shill-Proof Auctions
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3736252.3742623.pdf
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342.79 KB
Format
Adobe PDF
Checksum (MD5)
52e08582c75d185705a853b13338a8ee
Author(s)
Komo, Andrew
Kominers, Scott
Roughgarden, Tim
Date Issued
July 2, 2025
Publisher
Association for Computing Machinery
Citation
Andrew Komo, Scott Duke Kominers, and Tim Roughgarden. 2025. Shill-Proof Auctions. In Proceedings of the 26th ACM Conference on Economics and Computation (EC '25). Association for Computing Machinery, New York, NY, USA, 784.
Version
Final published version
Abstract
In an auction, a seller may masquerade as one or more bidders in order to manipulate the clearing price. We characterize single-item auction formats that are shill-proof in the sense that a profit-maximizing seller has no incentive to submit shill bids. We distinguish between strong shill-proofness, in which a seller with full knowledge of bidders' valuations can never profit from shilling, and weak shill-proofness, which requires only that the expected equilibrium profit from shilling is nonpositive. The Dutch auction (with a suitable reserve) is the unique (revenue-)optimal and strongly shill-proof auction. Moreover, the Dutch auction (with no reserve) is the unique prior-independent auction that is both efficient and weakly shill-proof. While there are multiple ex-post incentive compatible, weakly shill-proof, and optimal auctions; any optimal auction can satisfy only two properties in the set {static, ex-post incentive compatible, weakly shill-proof}.
Description
EC ’25, July 7–10, 2025, Stanford, CA, USA
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1145/3736252.3742623
