Arena raises $200M Series B at $3.1B valuation, launches agent Alignment Index
arena · x · 2026-10-13
Arena (born from UC Berkeley SkyLab, the team behind LMArena) announced a $200M Series B at a $3.1B valuation, with investors including a16z, Felicis, Kleiner Perkins, and Lightspeed. It also launched the Arena Alignment Index, built from real-world agent traces to evaluate how safely and reliably AI behaves in practice, covering three signals: Unauthorized Action, False Attribution, and Deceptive Completion. CEO Anastasios Angelopoulos presented it at the NYSE.
Related event: Arena Raises $200M Series B at $3.1B Valuation(2 posts)→
More from Venture
- 159 Cybercabs deployed, 319 registered, yet TSLA sits flat — the repricing game of chicken — JOBhakdi · 2026-10-13
- Jefferies sees a 2008-style credit angle in the AI boom as hyperscaler RPO backlog nears $2.3tn — SumitGup · 2026-10-13
- NVIDIA in talks to acquire Reflection AI, may repurpose GTM team for open-weight LLM push — thedealdirector · 2026-10-13
- Grok bot 'Grokbit' rakes in over $10K in fees — nima_owji · 2026-10-13
- Nvidia now takes 38% of top-5 hyperscaler IT capex, up from 11% in 2023, targeting 44% — Beth_Kindig · 2026-10-13
- Martin Casado: VCs obsess over business metrics too early — disruptive tech precedes business models — martin_casado · 2026-10-13