With OpenAI‘s announcement on Monday that, like Anthropic, it has confidentially filed for an initial public offering with the Securities and Exchange Commission, the race for the mega-AI lab IPO is officially on.

In a post on the OpenAI website, the company said that it recently submitted a confidential filing with the SEC. “We expect it to leak so we’re just announcing it,” the post said. “We have not decided on timing yet; it may be a while because there are things we want to do that are likely easier as a private company. But it’s a complicated set of tradeoffs and this gives us the option to go public sooner if that ends up being best.”

Anthropic’s announcement last week was equally light, saying that its proposed IPO ”will depend on market conditions and other factors.”

While the timing is uncertain, the fact that both companies have taken this step—getting draft versions of their IPO prospectuses into regulators’ hands for feedback—means they want to be ready to pull the trigger at any time. With a confidential S-1, a company can privately receive feedback on its disclosure statements from the SEC and make revisions before presenting the information to investors. Ensuring their IPO documents have the SEC’s blessing lets firms base their timing on other factors.

With SpaceX’s record IPO set to take place later this week, attention will turn to the two artificial intelligence giants as they take their rivalry to the public markets. And as PitchBook’s Kyle Stanford has previously posited, these three companies could break the IPO gates open or swallow the whole market and shut out other candidates.

In late May, Anthropic, maker of Claude AI, became the world’s most valuable startup after announcing it raised $65 billion in Series H funding at a USD 965 billion valuation. That surpassed OpenAI, which was most recently valued at $852 billion. After initially floating plans to go public at a $2 trillion valuation, SpaceX announced a target of $1.8 trillion.