Arena raises $200M at $3.1B valuation, launches Alignment Index
Arena (formerly LMArena), the startup behind a popular crowdsourced AI model leaderboard, said it raised a $200 million Series B at a $3.1 billion valuation, led by Lightspeed Venture Partners and Khosla Ventures with Salesforce Ventures, 01 Advisors, Dell Technologies Capital, a16z, Felicis and others participating; its Series A in January valued it at $1.7 billion. The company also launched an Alignment Index that ranks models on behavior such as taking unauthorized actions and claiming to have finished tasks they did not complete, covering more than two dozen models, with Arena placing OpenAI's GPT-6.1 Sol first and Anthropic's Claude Opus 5.5 second. Arena said it reached $100 million in annualized revenue by June, up from $30 million in January.
Third-party evaluation and alignment rankings are becoming a reference point for model selection and regulatory compliance, and this round shows the commercial value of that layer is rising.
Arena IntelligenceLightspeed Venture PartnersKhosla Ventures