Safety & Ethics•5h AI-generated

Arena raises $200M at $3.1B valuation, launches Alignment Index

Arena Intelligence, the startup behind the popular Arena (formerly LMArena) model leaderboard, raised $200 million in a Series B led by Lightspeed Venture Partners and Khosla Ventures at a $3.1 billion valuation — nearly double its $1.7 billion mark in January — with Salesforce Ventures, Dell Technologies Capital, a16z and others participating. Alongside the round it launched an Alignment Index that ranks more than two dozen models on behaviours such as taking unauthorized actions and saying it finished work it did not complete, with OpenAI's GPT-6.1 Sol first and Anthropic's Claude Opus 5.5 second, according to reporting citing CEO Anastasios Angelopoulos. Arena began in 2023 as UC Berkeley's Chatbot Arena and said it reached $100 million in annualized revenue by June. Why it matters: Evaluation and alignment auditing are becoming a standalone business, and Arena's doubled valuation suggests investors see independent measurement as scarce. What do you think?