AI
San Francisco-based Arena, formerly known as Chatbot Arena and LMArena, has raised $200 million in a Series B funding round at a $3.1 billion valuation to expand its AI model and agent evaluation platform.
Lightspeed Venture Partners and Khosla Ventures co-led the round, with participation from Salesforce Ventures, Dell Technologies Capital, 01 Advisors, Acrew Capital and Endeavor Catalyst. Existing investors, including a16z, Felicis and The House Fund, also participated.
Led by CEO Anastasios Angelopoulos, Arena was developed by researchers from the University of California, Berkeley. Its platform evaluates frontier AI models and agents across real-world tasks, helping assess their performance and capabilities.
The company has introduced Agent Arena for evaluating agentic AI, an Arena Alignment Index tracking unauthorised actions, false attribution and deceptive task completion, and Max, an agent router that reportedly reduces costs by 37%.
Arena reports over $100 million in annualised revenue, 350 million platform sessions, 62 million votes and more than 1,000 model evaluations across multiple AI categories.
The fresh capital will support platform expansion, alignment measurement and real-world AI evaluation.
