Polymarket Traders Bet $119K on OpenAI's Valuation Dropping to $750B by Year-End

Somewhere on Polymarket, traders have put between $119K and $132K behind the idea that OpenAI’s IPO closing market cap will land in the $500B to $750B range. The catch: the market itself thinks there’s only a 4-6% chance that actually happens.

That’s a bet against a company currently valued at $852B on private markets.

The contract in question asks traders to predict OpenAI’s IPO closing market capitalization, broken into various brackets. The $500B to $750B bracket, which would represent a meaningful haircut from the company’s last private valuation, has attracted a respectable amount of volume despite its long-shot odds.

But the real star of the contract isn’t any valuation bracket. It’s the “No IPO” outcome, which commands a probability of 62-67%. In other words, roughly two-thirds of the money thinks OpenAI simply won’t go public before the deadline.

The original market sentiment had pegged an 18% chance of OpenAI’s valuation falling to $750B by year-end, though Polymarket’s conditional pricing for that bracket in an IPO scenario has since compressed to the low single digits.

OpenAI raised $122B in March 2026, a round that valued the company at $852B post-money. Secondary market implied valuations have pushed even higher, reaching around $894B as of late August 2026.

There’s also the Sam Altman factor. Reports from June 2026 indicated that OpenAI’s CEO has expressed a clear preference: no IPO unless the company can command a valuation above $1 trillion. Some analysts have speculated that this $1T threshold could push any potential IPO into 2027.

Discussions in late 2025 actually centered on $750B as a target valuation for potential fundraising. The jump to $852B happened quickly, and quick jumps can reverse.

There’s also a structural argument about IPO discounts. If OpenAI were to IPO in a risk-off environment, a $750B market cap would represent roughly an 11-12% discount to the March 2026 private round, which is within the range of historical IPO haircuts for overvalued tech companies.

The fact that traders are pricing a nearly two-thirds probability of no IPO at all reflects deep uncertainty about the public market window for mega-cap tech listings. OpenAI’s apparent willingness to wait for a valuation above $1 trillion only reinforces that pattern.