The season of the mega IPOs is gathering momentum.
Just days before SpaceX is expected to begin trading publicly, Anthropic, the artificial intelligence company behind Claude, confidentially filed for an initial public offering, officially taking its place on the starting line of what could become the largest IPO cycle in modern market history.
The company did not disclose the size or timing of the offering, saying any deal would depend on market conditions.
But the filing means Anthropic could come to market as early as this fall. OpenAI is also widely expected to file for an IPO in the coming weeks.
Together, SpaceX, Anthropic, and OpenAI are expected to raise roughly $200 billion in quick succession, creating a new set of questions for investors already navigating record-high equity markets powered by enthusiasm around artificial intelligence.
The debate is no longer simply about whether these companies deserve trillion-dollar valuations.
The larger question is what happens when some of the most valuable private companies in the world suddenly become investable.
Will the offerings suck liquidity from the rest of the market? Will investors have enough capital to absorb them? And if they do, what happens after the initial excitement fades?
Likely impact of the IPOs on indices and passive investing
If SpaceX, OpenAI, and Anthropic debut at or above their latest private valuations, the consequences could extend far beyond Silicon Valley.
According to commonfund, IPOs above the $1 trillion mark would immediately place the companies among the ten largest constituents of the S&P 500 once included in major indices.
They would outrank established giants such as Costco and JPMorgan Chase by market value.
That possibility has fueled expectations that passive funds tracking major indices would eventually be forced to buy large quantities of stock.
Yet market participants caution that such inclusion is far from guaranteed.
“Many investors assume that a high-profile IPO quickly enters the major indices and then benefits from mechanical purchases by passive funds. It can happen, but it’s not automatic,” said Jean Fusshoeller, portfolio manager at Capital at Work.
He noted that profitability and seasoning requirements have traditionally slowed entry into the S&P 500.
However, S&P Dow Jones Indices recently opened a consultation on potential rule changes that could reduce waiting periods and potentially relax profitability requirements for exceptionally large companies.
“If adopted, these changes could significantly affect the timing and magnitude of passive demand,” Fusshoeller said.
He added that expectations themselves can become a market force.
“Investors often incorporate inclusion into indices before it actually happens. Expectations alone can move prices. If these expectations turn out to be too optimistic, the reversal can be just as abrupt.”
Could mega IPOs divert investor capital away from other sectors?
Even if passive funds ultimately become buyers, investors are asking a more immediate question: who will fund the IPOs in the first place?
Unlike previous market cycles, cash levels among institutional investors are already unusually low.
Bank of America data shows fund managers’ cash allocations have fallen below 4% for the first time since February 2024.
The decline reflects years of money flowing into equities, particularly AI-linked names that have powered the market higher.
In practical terms, investors are already close to fully invested.
That means capital allocated to SpaceX, OpenAI, and Anthropic may need to come from positions elsewhere in the market.
The concern has sparked warnings that the IPOs could temporarily divert investor attention and capital away from other sectors.
Along with the IPOs, Alphabet has also announced an $80 billion equity issuance to fund its AI computing infrastructure buildout.
Alphabet said it plans to issue $30 billion in concurrent underwritten public offerings consisting of $15 billion of mandatory convertible preferred stock and $15 billion in its class A and class C common equity.
Another $10 billion of stock will be sold to Berkshire in a private placement.
Alphabet also said it plans to issue $40 billion of stock in an “at-the-market” offering starting in the third quarter of 2026, which might add to the liquidity problem.
“Let’s see: $80 billion for GOOGL, probably $100 billion for Anthropic, $100 billion for OpenAI (maybe more) and $100 billion for SpaceX and $100 billion for Amazon? does this market have $500 billion in spare change. What has to be sold to raise it???” CNBC host Jim Cramer said in a post on X this morning.
Why are some strategists unconcerned
However, not everyone is convinced.
Ed Yardeni, president of Yardeni Research, argues that fears of an AI-driven liquidity drain are exaggerated.
“Fears are mounting that the AI-3 IPOs will suck the oxygen out of the rest of the stock market. We aren’t as concerned,” the firm said.
The numbers provide some context.
The combined fundraising target of roughly $200 billion appears substantial, but it remains small relative to a Wilshire 5000 market capitalization of $75.6 trillion and an S&P 500 worth nearly $60 trillion.
Yardeni also noted that US markets absorbed approximately $232 billion in new equity issuance over the past year and more than $450 billion during 2021, suggesting that investors have handled similar capital demands before.
Retail investors could also play a significant role.
“We have already personally received emails from our brokers inviting us to participate in the SpaceX IPO,” Yardeni said.
With 62% of American adults owning stocks and retirement assets exceeding $20 trillion, even as household equity ownership remains near record levels, Yardeni believes demand could prove deeper than many expect.
The real risk may be too few shares
Ironically, the bigger issue may not be insufficient demand but insufficient supply.
Nearly all of America’s publicly listed technology giants have free floats exceeding 85%, with the notable exception of Meta, where founder Mark Zuckerberg still controls about 13% of the company’s shares more than a decade after its 2012 IPO.
By contrast, SpaceX, Anthropic, and OpenAI are expected to debut with relatively limited free floats, as lock-up agreements will initially prevent founders, employees, and early investors from selling their stakes.
While those restrictions will eventually expire, bringing trillions of dollars worth of additional shares to public markets over time, the process is likely to unfold gradually rather than all at once.
SpaceX is expected to float only around 4.3% of its shares.
Anthropic and OpenAI are also anticipated to come public with relatively small free floats.
That creates the possibility of a powerful supply-demand imbalance, particularly if index providers accelerate inclusion timelines, Yardeni said.
Yardeni cited estimates suggesting S&P 500 index funds alone could absorb nearly one-fifth of SpaceX’s public float within six months.
Nasdaq-100 and Russell 1000 funds could absorb another 24%.
“This is forced buying colliding with a very limited supply,” Yardeni said.
The situation could create dramatic price swings, especially during the early months of trading when insider lock-up restrictions prevent founders, employees, and early investors from selling shares.
Over time, however, those restrictions will expire, gradually increasing the supply of publicly traded stock.
Why late investors may face weaker returns after IPO debuts
The transition of these companies into public markets is therefore likely to play out over years rather than days.
Historical data, however, suggests that many heavily anticipated IPOs struggle to justify their valuations over time, leaving late-arriving investors vulnerable to underperformance.
Research by University of Florida professor Jay Ritter found that the average IPO between 1980 and 2024 underperformed the broader market by 20 percentage points over the three years following listing.
Companies valued at more than 40 times revenue underperformed by 58 percentage points.
SpaceX, based on recent private-market valuations, would enter public markets at more than 90 times revenue.
There is also a broader historical pattern.
Waves of blockbuster IPOs have often arrived near the end of bull markets rather than the beginning.
The listing boom of 2020 and 2021 preceded a sharp market downturn, while similar surges in the late 1990s and before the 2008 financial crisis were followed by significant corrections.
The risk is not necessarily that SpaceX, OpenAI, or Anthropic disappoint individually. The greater concern is that all three have become symbols of the AI trade itself.
Artificial intelligence-related companies already account for an outsized share of US market value.
If investor enthusiasm toward AI were to cool, the consequences could extend well beyond the new listings.
For now, investors appear eager to participate.
But as the largest IPO wave in years approaches, markets are about to discover whether demand for AI can be as powerful in public markets as it has been in private ones.
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