OpenAI's official announcement and rollout of GPT-5.5 today—detailed in a blog post and confirmed via posts from CEO Sam Altman and the company account—has driven trader consensus to 100% implied probability for an April 23 release, as the large language model is now available to paid ChatGPT and Codex subscribers, excelling in agentic coding, research, and tool use with efficiency gains over GPT-5.4. This rapid iteration, just seven weeks after the prior model, underscores OpenAI's accelerated development pace amid competition from Anthropic's Claude. While skin-in-the-game bets reflect near-certainty on confirmed deployment, edge cases like disputes over exact rollout timing or resolution criteria could theoretically challenge it, though such risks appear negligible given the public availability.