Source: Sharecast
OpenAI said it has not yet decided on timing, noting that the process may take time because "there are things we want to do that are likely easier as a private company". OpenAI was valued at $852bn in March.
The move comes days after rival Anthropic also filed confidentially for an IPO, having last been valued at $965bn.
OpenAI's filing follows a legal win for chief executive Sam Altman and president Greg Brockman, after a California jury ruled that Elon Musk's lawsuit against the pair was filed outside the statute of limitations. Musk has said he will appeal, calling the verdict a "calendar technicality".
The IPO could deliver a significant windfall for Microsoft, one of OpenAI's largest backers, after companies amended their partnership last October, allowing OpenAI to transition fully to a for‑profit structure. Under that deal, Microsoft received 27% of OpenAI Group PBC, valued at $135bn, while the non-profit arm received a $130bn stake.
Reporting by Iain Gilbert at Sharecast.com