SpaceX, Anthropic, and OpenAI IPOs could drag equity markets for years, warns Rob Arnott

Rob Arnott has a message for anyone who thinks the coming wave of tech mega-IPOs is unambiguously great news for markets: think again.

The founder and chairman of Research Affiliates warned on June 5 that forthcoming listings from SpaceX, Anthropic, and OpenAI could create a prolonged drag on the broader equity market, diverting tens of billions of dollars away from existing stocks over multiple years.

The capital vacuum problem

SpaceX’s IPO is expected to raise approximately $75 billion, which would make it the largest public listing in history. To put that in perspective, Saudi Aramco’s 2019 IPO raised about $25.6 billion. Anthropic has filed confidential IPO paperwork following a funding round that valued the AI company at nearly $1 trillion. OpenAI is also expected to pursue a public listing.

Arnott’s concern isn’t about any single IPO in isolation. It’s the cumulative effect. When this much new equity hits the market in a compressed timeframe, existing shareholders in legacy companies get crowded out. Arnott described the dynamic as “drip, drip pressure,” referring to the ongoing impact of repeated share floats and the mechanical index rebalancing that follows each major listing.

The index rebalancing cascade

On May 28, Arnott noted that SpaceX would be eligible for inclusion in the Nasdaq 100 after just 15 days of trading, and the S&P 500 in approximately six months. He was actually bullish on SpaceX itself, citing the company’s small initial float and the near-certainty of rapid index inclusion as factors that would drive its stock price higher.

Index funds tracking the Nasdaq 100 or S&P 500 must maintain specific weightings, so adding a company worth hundreds of billions means mechanically reducing exposure to existing constituents. Each secondary offering, each lock-up expiration that releases insider shares, each subsequent index reconstitution repeats the cycle. That’s the “drip, drip” Arnott is warning about.

What this means for crypto and risk assets

Arnott’s analysis focuses squarely on traditional equity market dynamics, without mentioning crypto or digital assets.

If SpaceX alone pulls $75 billion from the market and Anthropic follows with a listing at anything close to its near-$1 trillion valuation, the total capital displacement could rival the magnitude of entire asset classes.

Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our Editorial Policy.