Investors eager to acquire shares in private tech giants like OpenAI, Anthropic, and SpaceX may face unexpected consequences when these companies go public in 2026. According to research from asset management firm GMO, the wave of mega IPOs anticipated this year could create pressure on the broader stock market. The firm warns that the surge of new shares entering the market without proportional demand growth could trigger price declines across major indices.
Ben Inker, GMO’s co-head of asset allocation, predicted in a report last month that at least two of these private giants will go public in 2026. The asset manager, co-founded by legendary investor Jeremy Grantham, has consistently expressed skepticism about artificial intelligence valuations over recent years.
How Tech IPOs Could Impact Stock Market Performance
The anticipated tech IPOs operate under basic supply and demand principles that govern all tradable assets. When substantial new share supply enters the market without corresponding demand increases, downward price pressure typically follows. Additionally, these companies will not immediately join the S&P 500 upon listing, potentially triggering outflows from the benchmark index as investors reallocate capital to purchase newly available shares.
GMO’s research reveals a striking historical pattern regarding IPO activity and market valuations. According to Inker, each 1% increase in market capitalization through IPOs eventually leads to approximately a 7.5% decrease in stock market prices. This relationship suggests that the combined market debut of multiple tech titans could generate significant headwinds for equity markets.
The Supply and Demand Challenge for Markets
The timing and magnitude of potential price impacts may vary according to GMO’s analysis. Initially, the market might experience upward momentum following these high-profile listings. However, longer-term pressures emerge as more stockholders gain the ability to monetize their holdings, creating sustained challenges for U.S. equity markets.
Inker elaborated on this timeline effect in his report, noting that post-IPO enthusiasm often gives way to selling pressure. The increased number of shareholders seeking liquidity can overwhelm buying interest, particularly when multiple billion-dollar companies list within a compressed timeframe.
GMO’s Contrarian Outlook on 2026 Stock Market Returns
GMO’s pessimistic stance extends beyond concerns about tech IPOs alone. Inker told Business Insider in December that the S&P 500 is positioned for negative returns in 2026, a forecast that stands well outside Wall Street consensus. His bearish call incorporates expectations of rotation away from the market’s largest artificial intelligence stocks, which have driven much of recent equity gains.
The firm has identified alternative opportunities for investors seeking positive returns in global markets. According to GMO, Japanese small-cap stocks and European value stocks represent more attractive investment prospects compared to U.S. large-cap equities. These recommendations reflect the firm’s value investing philosophy and contrarian approach to market positioning.
Market Excitement Versus Historical Patterns
Meanwhile, investor enthusiasm for accessing shares in companies at the forefront of artificial intelligence development remains exceptionally high. The potential public debuts of OpenAI, Anthropic, and SpaceX represent rare opportunities to invest in companies that have achieved massive private valuations and technological prominence. However, GMO’s historical analysis suggests that such excitement may cloud judgment about supply-demand dynamics.
Inker specifically noted that 2026 is likely to witness IPO excitement levels not seen in considerable time. The convergence of multiple mega-cap technology listings within a single year creates an unusual market environment that historical patterns suggest could prove challenging for existing shareholders across the broader market.
The timing and scope of these anticipated IPOs remain subject to market conditions and company decisions, with no official listing dates confirmed by OpenAI, Anthropic, or SpaceX. Investors and market analysts will monitor regulatory filings and company announcements throughout 2026 for clarity on when these transformative public offerings might occur.
