OpenAI Jumps 32%, Airtable Crashes 56% As Private Market Returns Diverge

OpenAI surged 32.3% in September while Airtable plunged 56.1%, highlighting a widening divide in private-market performance as investors become more selective and secondary-market share discounts deepen.

The divergent returns came as Forge’s equal-weighted Private Market Index rose 1.4% during the month, masking sharp swings among individual companies. The firm’s October private-market update points to a market where gains remain concentrated in a handful of high-profile businesses while other companies face steeper valuation pressure.

OpenAI was the largest contributor to the cap-weighted Forge Accuidity Private Market Index, which gained 3.4% in September. Defense technology company Anduril also supported performance, rising 7.3%, while publicly traded SpaceX (NASDAQ:SPCX) gained 5%.

The gains were offset by losses elsewhere. Airtable recorded the steepest decline among the index’s tracked companies, followed by Postman, which fell 33.7%. Cryptocurrency exchange Kraken dropped 19.1%, while AI chip startup SambaNova Systems declined 12.4%.

Airtable’s drop reflected its acquisition by Bending Spoons at a lower-than-anticipated price of $1.28 billion, according to Forge. Meanwhile, Fin, formerly Intercom, jumped 78.7% after Salesforce (NYSE:CRM) acquired the company for $3.6 billion on Sept. 10.

The contrast highlights how acquisition prices, company-specific developments and differences in investor demand can drive widely divergent outcomes across private markets.

Private Market Buyers Gain Leverage

The uneven performance comes as the balance between buyers and sellers shifts in the secondary market.

Buy-side indications of interest accounted for 43.5% of new and updated indications on the Forge Marketplace in September, down from 45% in August and 48% in July. The decline marked the fourth consecutive monthly decrease and brought buyer participation to its lowest share in roughly two years.

At the same time, the median secondary-market transaction traded at a 9% discount to the company’s last primary funding-round valuation, compared with a 3% discount in August.

Pricing also softened among higher-priced transactions. The 90th percentile of secondary trades fell from a 58% premium to the last primary funding round in August to a 15% premium in September. The 75th percentile declined from an 11% premium to 6%.

The changes suggest that rising seller participation is giving buyers more negotiating power, potentially creating opportunities for investors seeking exposure to private companies at lower prices.

However, Forge cautioned that monthly pricing shifts can reflect changes in the mix of companies being traded rather than a broad repricing of the entire market.

$20 Billion Valuations Still Hold Up

Despite the divergence in returns and softer secondary-market pricing, many of the largest private companies have maintained their valuations.

Of the 40 companies tracked by Forge that have reached valuations of at least $20 billion, 28, or 70%, maintained that threshold in their latest funding round or exited at a higher valuation.

Among the companies in this tier are Anduril, which Forge valued at $123.8 billion, fintech firm Ramp at $60 billion, and AI startup Cognition at $48 billion.

Five companies raised capital at valuations of $20 billion or more since early August, compared with eight during all of 2025, according to Forge.

The findings suggest that private-market weakness is not uniform. While some companies continue to attract investor capital at high valuations, others are experiencing sharp repricing as acquisition outcomes and secondary-market activity reshape expectations.

For investors, the challenge is distinguishing companies with durable growth prospects from those whose previous funding-round valuations may no longer reflect what buyers are willing to pay.

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