SpaceX, OpenAI, and Anthropic IPOs may usher in an era of turbulence for big tech companies.

The high-profile initial public offerings (IPOs) expected on the US stock exchange, such as SpaceX – which filed its prospectus this Wednesday, May 20 – Anthopric, and OpenAI, are expected to trigger an unprecedented wave on Wall Street, especially given the new rules recently implemented by Nasdaq.

The new format, which came into effect at the beginning of May, includes measures to accelerate the entry of newly listed large-cap companies into the Nasdaq 100 index. This means that billions of dollars will automatically flow to the three companies shortly after their IPO, boosting their share prices but forcing investors to sell other shares.

Elon Musk's SpaceX filed for an IPO that is expected to be the largest in history, hours before OpenAI's plans to go public were revealed and rival Anthropic stated it was on track to turn a profit, paving the way for its own initial public offering.

The rocket manufacturer will make a relatively small number of shares available to public investors in its IPO next month, a small “free float” that, under old rules, would exclude the company from indices tracked by trillions of dollars in passive investments.

However, Nasdaq relaxed its rules in the battle for SpaceX's listing against its competitor NYSE, allowing the shares to enter the Nasdaq 100 after only 15 days. SpaceX and other new companies will also receive a weighting in the index equivalent to three times the value of their traded shares. S&P Dow Jones is also conducting consultations on changes that could accelerate the entry of the shares into the S&P 500.

The initial impact on the rest of the index will be limited by the relatively small number of shares offered, but will likely increase after the lock-up period ends, which will be staggered over the first 180 trading days, according to SpaceX's prospectus.

JP Morgan estimates that if 50% of the company's shares were eventually launched on the stock exchange, with a valuation reaching US$2 trillion, passive investors would have to sell US$95 billion worth of shares in the eight largest technology companies on Wall Street. SpaceX aims for a valuation of US$1.75 trillion.

According to the bank's calculations, Nvidia stands to lose the most, with an outflow of at least US$21 billion. Apple follows with US$17 billion, and Microsoft with US$12 billion. Even Tesla, also owned by Musk, will suffer losses, estimated at around US$5 billion.

But it won't just be these big tech companies that will lose shareholders. Investors are also preparing to sell shares in smaller companies, which may be delisted from indices later this year to make way for SpaceX and the arrival of other tech giants.