ACV Auctions Q4 Revenue Up 15%, Shares Fall 36% Amid AI Concerns and Below-Expectation 2026 Guidance

ACV Auctions reported Q4 revenue of $183.6M (up 15.1%) and guided 2026 revenue of $845M to $855M with adjusted EBITDA of $73M to $77M. Despite CEO George Chamoun's claim that ACV is the AI disruptor in wholesale auto, shares fell 25% post-earnings, down 36.16% YTD. The company's no-reserve auction format, the ACV Guarantee, reached 19% of Q4 mix, and Chamoun said he would be "thrilled" to see it reach the mid-20% range in 2026.