Rumor: OpenAI’s "Spud"

A blog post published April 11 says OpenAI’s next model, codenamed “Spud,” finished pretraining around March 24 and could ship before April 30 — but OpenAI has not announced it. (abhs.in) The post says prediction market Polymarket was pricing roughly 78 percent odds of an April release when it was written, and it labels the model name “GPT-5.5” as unconfirmed. The same site says “Spud” is an internal codename and that release timing, pricing, and product scope remain unknown. (abhs.in, abhs.in) Pretraining is the first large stage of model building, where a system learns patterns from vast amounts of text and other data before later tuning and safety work. OpenAI described GPT-4.5 in February 2025 as a model that “scales pre-training further,” which is the closest official public reference point for this kind of claim. (openai.com, openai.com) The rumor lands after OpenAI spent 2025 shipping named models through official channels rather than teasing them in advance. OpenAI announced GPT-4.5 on February 27, 2025, and GPT-4.1, GPT-4.1 mini, and GPT-4.1 nano on April 14, 2025. (openai.com, openai.com) OpenAI’s current public developer materials do not mention any model called “Spud” or “GPT-5.5” in official docs tied to the application programming interface. The platform documentation instead shows currently documented model lines such as GPT-4.1 and newer GPT-5-series entries on the platform site. (platform.openai.com, developers.openai.com) That leaves the report in the category of market chatter, not product confirmation. The abhs.in article is explicit that it is assembling leaks, timing signals, and betting-market odds rather than citing an OpenAI launch post, pricing page, or application programming interface release note. (abhs.in, abhs.in) One reason the rumor is getting attention is that OpenAI has used “.5” branding before for a larger general-purpose model between major generations. OpenAI said GPT-4.5 was its “largest and most knowledgeable model yet” and framed it as a research preview rather than a full next-generation replacement. (openai.com, openai.com) Another reason is that OpenAI’s release pattern has been uneven across products. GPT-4.1 launched “starting today” for developers in the application programming interface in April 2025, while other models have appeared first in ChatGPT, partner products, or limited previews. (openai.com, platform.openai.com) As of April 12, the hard fact is narrower than the rumor: there is a speculative report, and there is no official OpenAI announcement to match it. If that changes, the first concrete signals will likely be an OpenAI blog post, system card, or model documentation page — not a codename leak. (abhs.in, openai.com, platform.openai.com)