OpenAI’s recent GPT-6 Astra release has driven trader sentiment toward a 55.5% implied probability it finishes as the second-best lab on Code Arena’s WebDev leaderboard by year-end. The model quickly posted top or near-top scores in community-voted agentic coding tasks, closing gaps with Anthropic’s Claude Opus 5.5 and Fable 5.1 series that have led much of 2026. This positions OpenAI as the primary challenger in a tight race defined by iterative frontend workflows, tool use, and real-user preference votes. Lower odds for Google, Alibaba, and others reflect their current 100-plus point deficits on the Pareto frontier, though new model drops or category-specific gains could shift the deadlock before December resolution.