The secondaries market is offering an unusually clear view of what may be the most closely watched IPO horse race in history: OpenAI versus Anthropic.

For some time, the prevailing sentiment has been that OpenAI is falling behind Anthropic, and prospective buyers across the secondaries market appear to share that view. Demand for Anthropic shares is far exceeding demand for OpenAI shares, according to pre-IPO market sources. While the sense is that enthusiasm for Anthropic has intensified in recent months — including the demand explosion surrounding the company's mammoth $65 billion fundraise — Anthropic shares have been the most prized assets in the space for some time.

The secondaries market, where shares of private companies are bought and sold before an IPO, has become one of the few public windows into how institutional investors are pricing the leading AI labs — and the widening gap in entry minimums between the two companies is itself a signal of where that money wants to be.

"Anthropic has been the most in-demand name in the secondary market for about a year," Javier Avalos, CEO of private markets platform Caplight, wrote to Fortune, adding that he has seen roughly $1.5 billion in interest in Anthropic since the beginning of Q2 2026.

Back in May, demand for Anthropic shares was described as "a pressure cooker ready to explode." In the aftermath, the company has run a tight ship regarding who is allowed to buy its shares on the secondary market.

"In the secondary space, Anthropic really tightened its process around letting people into its cap table," said Clara Vydyanath, general partner at Underline Capital. "A lot of cap-table GPs have warehoused positions… and they're now piecemeal-selling blocks worth $20 million, $50 million, $100 million at a time."

According to Caplight data, Anthropic's valuation currently sits in the $1.4 trillion ballpark, up more than 400% year-over-year, Avalos said — a figure that aligns with what Vydyanath is seeing. And investors without millions to deploy are probably not getting into Anthropic at all.

"I think below $25 million is difficult," said Vydyanath. "It's [generally] got to be $50 million-plus at valuations clearing around $1.3-1.4 trillion."

Even then, access to Anthropic can be a struggle regardless of how much money an investor wants to commit.

"It's an incredibly cluttered market," said Christine Healey, founder of broker firm Healey Pre-IPO. "Even some investors trying to do $10 million or $100 million ticket sizes can struggle to find access… Based on what I've seen, Anthropic is a market where demand far outweighs supply, probably by 3x, 4x, 5x demand versus supply."

OpenAI presents a stark contrast. Entry into that company on the secondary market likely requires deploying between $500,000 and $1 million, several sources said. Avalos added that demand for OpenAI shares has somewhat recovered from earlier-year lows in recent months.

For some investors, that gap may represent an opportunity — though such views reflect the perspectives of individual market participants rather than settled consensus on either company's worth.

"Right now, what I can say is that OpenAI feels underpriced and Anthropic feels overpriced," said Underline's Vydyanath. "In reality, OpenAI is a phenomenal deal right now."