Market readiness for SpaceX, Anthropic, and OpenAI IPOs sparks debate on future tech funding

The prospect of three colossal flotations from SpaceX, Anthropic and OpenAI has raised an obvious question: can equity markets absorb listings of this scale without strain? For now, the answer appears to be yes, if only because the American market is unusually deep. Even a combined fundraising effort running into hundreds of billions of dollars would be modest beside the trillions already tied up in the country’s largest share indices.

SpaceX is understood to be planning the first move, with reports pointing to a Nasdaq debut on June 12 and a target raise of $75 billion at a valuation of between $1.75 trillion and $2 trillion. The prospectus is said to reserve a portion of stock for retail buyers, while BlackRock is reportedly among the institutions weighing a substantial anchor commitment. Anthropic has also filed confidentially for an IPO, and OpenAI is widely expected to follow, potentially setting up a rush of blockbuster offerings in quick succession.

In context, these are exceptional sums, but not system-breaking ones. Saudi Aramco still holds the record for the largest debut raise, having taken in $29 billion in 2019. By comparison, the market capitalisation of companies in the S&P 500 alone runs to tens of trillions of dollars, and the broader Russell 3000 is larger still. That scale matters because it means the market can, at least initially, digest the new supply without forcing dramatic changes in most portfolios.

Index mechanics are also likely to soften the immediate impact. Most benchmarks weight companies by free float, not by headline valuation, so only the shares actually released into public trading are counted at first. That means SpaceX’s opening weight would be relatively small even on a huge valuation, and the effect on tracker funds would be limited. Nasdaq has already shortened the waiting period before inclusion, but the larger point is that float restrictions and staggered lock-ups prevent these companies from flooding the market all at once.

That staggered release may matter more than the IPO itself. Lock-up periods will initially stop founders, employees and early backers from selling much of their stock. Over time, though, those restrictions will fall away in stages, and the public float will expand. In SpaceX’s case, reports suggest Elon Musk’s holding, together with portions owned by significant investors, would remain locked for a year, while other tranches could become saleable after the first quarterly results and on later milestones. Anthropic and OpenAI would likely follow a similar pattern.

This means the real test for markets may come not on listing day, but in the years afterwards. Investors who buy into the story at the outset may discover that enthusiasm and pricing are not the same thing. Jay Ritter, the University of Florida academic who has studied long-run IPO performance, has found that newly listed shares have historically lagged the wider market over the three years after debut, with the weakest results often seen in the most richly valued offerings.

There is also a broader signal embedded in these deals. Big IPO waves have often arrived near the end of bullish cycles, when companies sense that investors are willing to pay the highest prices. The last major burst of listings in 2020 and 2021 preceded a bear market, and earlier booms were followed by more severe declines. If the current crop disappoints, it could unsettle sentiment well beyond the names themselves.

That is partly because the three companies sit at the centre of the artificial-intelligence narrative that has powered much of the market’s recent gains. The biggest listed AI-linked firms already represent a striking share of the S&P 500’s value. A setback for one IPO would not matter much to passive investors; a broader change in faith in AI could matter a great deal more.

There is another layer to the story, too: capital is becoming scarcer just as the technology sector is demanding more of it. For years, cash-rich giants have been buying back their own shares rather than issuing new ones. Now many are redirecting funds towards AI investment, while also tapping debt markets. The newcomers are, in effect, adding fresh supply to a market that had become accustomed to a shortage of it.

For that reason, the biggest question may not be whether the market can swallow the initial offerings. It almost certainly can. The larger concern is whether the arrival of SpaceX, Anthropic and OpenAI marks the start of a more demanding phase for investors, one in which the market must finance far more ambition, tolerate greater volatility and perhaps accept that the era of easy abundance in tech equities is giving way to something tighter.