OpenAI

OpenAI is a capped-profit company whose consumer product, ChatGPT, and developer API became default interfaces for generative models. A large share of startups call the API rather than train a frontier model.

Microsoft invested billions, took a large economic stake, and became the exclusive cloud for OpenAI's heaviest training and serving. Microsoft also distributes the models inside Copilot, Windows, and Azure. The Federal Trade Commission has examined whether arrangements like this function as mergers or exclusive deals that were never filed.

Distribution through Microsoft products is a tying story if customers who want Office are steered to one model and cannot easily substitute another. It is ordinary distribution if customers can still call a rival API. The difference is default placement and technical friction, the same facts as the Google search default cases.

OpenAI's own API terms, rate limits, and data-use rules are a platform for developers. A ban, a price change, or a rule against competing with ChatGPT can remove an app's backend overnight. That is platform-suspension risk even though the company is younger than Apple or Google.

The Microsoft partnership concentrates compute, distribution, and a leading model lab. Enforcers ask whether rivals can rent equivalent compute and reach customers who live in Office.

Default Copilot placement is the new search-default question: a preselected model captures habit before a comparison is made.

API dependence creates lock-in for apps. Prompts, evals, and fine-tunes are not a clean export.

Exclusive access to a next model, even for a few months, can be an exclusivity restraint if it is bought rather than earned.

People meet OpenAI as a chatbot and as a feature inside software their employer already pays for. The choice of model is often made by the employer or the default, not by a settings screen.

A startup whose product is a thin layer on the API has one critical supplier. A pricing or policy change is a supply shock, not a normal software update.