Why the exploding secondaries market is hard to pin down

Secondaries are an elephant-sized black box. 

The market is mammoth, expanding, and—here’s the kicker—we have no clue how big it really is. The secondaries market has exploded in recent years, driven by a simple problem: companies are staying private longer, exits have dried up, and investors need inventive ways to return cash to their LPs.

New PitchBook data estimates that, in 2025, somewhere between $62.5 billion and $120.9 billion were traded in U.S. direct secondaries. Now, $58 billion-plus is a helluva range, but more importantly: that’s a margin of error larger than many markets. (The worldwide total addressable market for, say, soap is around $50 billion.) One point of comparison: $50 billion was the volume for all of 2024. 

PitchBook has good reason for keeping its estimates broad. The secondaries market, as big as it’s gotten, is structurally opaque. There are a few rules that force disclosure and investors—frequently small firms and wealthy individuals—often buy shares with incomplete information. The FOMO logic isn’t all that different from public markets. If you like OpenAI, you want a piece of it—it’s the same as someone buying Disney stock because they believe in the name. 

The difference, of course, is that nothing is publicly reported. Some deals get done through large institutions (Goldman Sachs, Morgan Stanley, and Charles Schwab all did 2025 acquisitions to bolster their secondary operations). Those Wall Street-funneled deals are for the big fish—if you fancied a few-hundred-million-dollar stake in a company like Anduril. But much of the market runs through smaller operations, sometimes just one or two people, brokering deals for buyers looking to put in a couple hundred thousand.

And this is where the market grows lopsided, as everyone chases a handful of companies. PitchBook points out that the top 20 startups on private stock marketplace Hiive accounted for an astonishing 86.4% of secondary trading value in the fourth quarter of 2025. The top five (names like OpenAI and SpaceX) accounted for 55.6% of that volume. 

So, how big is the secondary market? What can we actually know right now? PitchBook goes straight to the midpoint of that range, $91.7 billion, then adds their estimate for GP-led venture secondaries volume, $14.6 billion. That gets the 2025 market for U.S. venture secondaries to $106.3 billion.

And that’s almost definitely conservative. We’ve lost track of an elephant.

See you tomorrow,

Allie Garfinkle
X: @agarfinks
Email: alexandra.garfinkle@fortune.com
Submit a deal for the Term Sheet newsletter here.

Joey Abrams curated the deals section of today’s newsletter. Subscribe here.

This story was originally featured on Fortune.com