Autobidder's Dilemma: Why More Sophisticated Autobidders Lead to Worse Auction Efficiency

Hanrui Zhang
NeurIPS 2024
Google Scholar

Abstract

The recent increasing adoption of autobidding has inspired the growing interest in analyzing the performance of classic mechanism with value-maximizing auto-bidders both theoretically and empirically. It is known that optimal welfare can be obtained in first-price auctions if auto-bidders are restricted to uniform bid-scaling and the price of anarchy is $2$ when non-uniform bid-scaling strategies are allowed.

In this paper, we provide a fine-grained price of anarchy analysis for non-uniform bid-scaling strategies in first-price auctions, demonstrating the reason why more powerful (individual) non-uniform bid-scaling strategies may lead to worse (aggregated) performance in social welfare. Our theoretical results match recent empirical findings that a higher level of non-uniform bid-scaling leads to lower welfare performance in first-price auctions.