Anastasios Angelopoulos is co-founder and CEO of Arena, formerly LMArena, the company behind the Chatbot Arena AI model leaderboard. He was a PhD student at UC Berkeley when the project was an academic effort, and his profile lists an undergraduate degree in electrical engineering from Stanford.
He led the project's transition into a company incorporated in April 2025. Arena raised a $200 million Series B at a $3.1 billion valuation in October 2026, co-led by Lightspeed Venture Partners and Khosla Ventures.