AI ranking platform Arena raises $200 million, valuation nearly doubles in 10 months.

Insight Beating AI News: AI model leaderboard Arena has completed a $200 million Series B funding round, valuing the company at $3.1 billion. The round was co-led by Lightspeed Venture Partners and Khosla Ventures, with participation from Salesforce Ventures, a16z, and other investors. Back in January this year, Arena had just closed a $150 million Series A round at a $1.7 billion valuation. Originating from a research project at the University of California, Berkeley, Arena initially let users anonymously compare responses from different AI models and generate leaderboards via voting. Now, the company is rolling out paid evaluation and analysis services for model providers and enterprises. Arena reported its annual recurring revenue (ARR) has grown from $30 million in January to $100 million in June. Currently, the platform draws tens of millions of monthly visitors. Official disclosures show the platform has accumulated 350 million sessions and 62 million votes to date, covering tasks including text, programming, image, and video. Alongside the funding, Arena also launched a new AI Agent security leaderboard, the Alignment Index. This leaderboard analyzed over 90,000 real sessions across 27 models, checking for unauthorized operations, misinterpretation of user requests, or false task completion reports by AIs. OpenAI models took all top five spots, with GPT-6.1 Sol leading at 87.9 points. The study also found that 48% of code debugging sessions involved false completion claims.