Private Share Trading Booms, Anthropic Leads While SpaceX IPO Looms

The private share trading market has hit a new gear, and the leaderboard looks nothing like it did a year ago. Glen Anderson, president of Rainmaker Securities, who has been brokering trades in private company shares since he founded the firm in 2010, described the secondary market as more active than he has ever seen it, with Anthropic replacing OpenAI as the dominant institutional trade and SpaceX's imminent public offering threatening to upend the entire dynamic.

OpenAI shares fell out of favor on the secondary market, in some cases becoming almost impossible to unload, as investors pivoted quickly to Anthropic. The numbers behind that shift are stark. At Next Round Capital, founder Ken Smythe revealed that despite approaching hundreds of institutional investors, not a single buyer could be found for OpenAI shares in recent weeks. Last year, such offerings would have vanished within days, but even at a discounted valuation of $765 billion, well below OpenAI's newest primary-round post-money figure of $852 billion achieved in its $122 billion raise, sellers found no takers. Anderson confirmed that secondary pricing for OpenAI had converged around that $765 billion implied mark.

Anthropic, meanwhile, has become the market's obsession. Buyers across secondary platforms have $2 billion in cash ready to deploy into Anthropic shares, reflecting a rotation driven by both relative valuation and revenue momentum. Valued at $380 billion in its $30 billion Series G round, Anthropic reached $14 billion in annualized run-rate revenue as of February 2026, growing 10x annually for three consecutive years. That growth trajectory, at a valuation roughly half of OpenAI's, has made it the more compelling risk-reward proposition for institutional buyers hunting exposure to the AI sector without paying the premium that has historically attached to OpenAI.

The already feverish market now faces a potential structural disruption from SpaceX. SpaceX confidentially filed for an IPO on April 1, 2026, in what would likely be a record offering. The company could seek a valuation of $1.75 trillion, with a listing targeted for around June. According to Reuters, lead bookrunners include Morgan Stanley, Goldman Sachs, JPMorgan Chase, Bank of America, and Citigroup, with 16 other banks involved in smaller roles, reflecting the scale of the transaction. SpaceX most recently completed a tender offer at an $800 billion valuation before its merger with Elon Musk's xAI pushed the combined entity's implied worth past $1.25 trillion.

For the secondary market, a SpaceX IPO of that magnitude cuts both ways. On one hand, it could absorb enormous institutional capital that would otherwise cycle through private platforms. On the other, a successful listing at or near the $1.75 trillion target could validate the pricing of other late-stage private companies and open the door for a wave of follow-on offerings from names like OpenAI, Stripe, and Databricks. 2025 was already a banner year for the pre-IPO trading market, with trading volume on the Rainmaker platform swelling to new highs as buyers who had been on the sidelines for most of the prior few years returned to a risk-on stance.

Whether SpaceX's debut accelerates or cools that momentum will depend heavily on how its first weeks of trading land, and on whether investors who have been circling Anthropic find their window narrowed by a public market that suddenly offers its own historic-scale AI bet.