Arena, the company behind the crowdsourced LMArena leaderboard, has raised $200 million in a Series B round at a $3.1 billion valuation, it announced on Thursday. 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.
The news comes roughly ten months after Arena's $150 million Series A in January, which valued the company at $1.7 billion post-money. Its valuation has therefore nearly doubled in that period, while annualized run-rate revenue grew from $30 million at the time of the Series A to $100 million in June, according to the company.
What Arena's $200M round means for AI benchmarks
Arena began in 2023 as a research project at UC Berkeley, where it crowdsourced rankings of AI models. The platform is free for consumers: users enter prompts or request vibe-coded projects, then rate which model performs better. Arena says it has tens of millions of monthly visitors.
In September of last year the company launched AI Evaluations, a commercial service that gives model labs and enterprises detailed performance analytics based on community feedback. That timing proved useful as AI labs discovered their models were gaming benchmarking tests, and enterprises increasingly wanted to know which model fit their own internal needs rather than relying only on standardized benchmarks.
Arena alignment leaderboard tracks lying and unauthorized actions
Arena has added an alignment category to its leaderboard, ranking models on issues such as unauthorized action, false attribution and what it calls deceptive completion. In its funding announcement, the company said AI is advancing faster than our ability to evaluate it, and that static benchmarks break down once models recognize they are being tested.
