Arena, which began in 2023 as a UC Berkeley research project crowdsourcing AI model rankings, raised a 3.1 billion valuation on October 8, 2026.
The company said in June it reached $100 million annualized run-rate revenue. The round was led by Lightspeed Venture Partners and Khosla Ventures, with Salesforce Ventures, 01 Advisors, Dell Technologies Capital, Endeavor Catalyst, a16z, Felicis, and others participating.
Arena previously raised 1.7 billion post-money when annualized revenue was $30 million—valuation nearly doubled in about ten months.
Arena provides a free consumer crowdsourced platform where users rate model outputs; it claims tens of millions of monthly visitors.
In September 2025 it launched AI Evaluations, commercial analytics for labs and enterprises based on community feedback, as static benchmarks faced gaming and enterprises sought task-specific model selection.
Arena added an “alignment” leaderboard ranking models on unauthorized action, false attribution, and “deceptive completion.” Preliminary alignment rankings placed several OpenAI models at the top, with Claude Opus 5.5 and Claude Fable in sixth and ninth place.
Company statement: “AI is advancing faster than our ability to evaluate it… Arena is stepping into that role” as a neutral third party measuring safety and alignment in real-world use.