OpenAI has established a pattern of major model releases roughly every 9 to 12 months. GPT-4 launched in March 2023, GPT-4 Turbo in November 2023, and GPT-4o in May 2024. The prediction market question of whether GPT-5.5 will arrive specifically on April 26, 2026, reflects trader interest in the next major generation of large language models from OpenAI's roadmap. This market is resolvable because OpenAI announces major releases publicly through blog posts, developer events, and API availability—making verification clear after the target date passes. The 0% current odds reflect trader consensus that an April 26 release is extremely unlikely. OpenAI typically signals major releases in advance through developer previews, regulatory disclosures, or partnership announcements, and no such signals currently point to April 26. Major AI releases require significant coordination across infrastructure, partnerships, and user onboarding, which prediction market traders are implicitly pricing into their current forecast. The April 30 market close provides a four-day window to confirm whether any surprise announcement occurs near the April 26 date. Traders here are essentially estimating the probability of an unexpected early release versus OpenAI's more typical development timeline spanning many months between major iterations.