Warren presses index firms on SpaceX IPO rule changes

Sen. Elizabeth Warren (D-Mass.) is pressing four major index providers over whether they changed their rules to accommodate SpaceX, OpenAI and Anthropic without adequate investor safeguards.

In a letter sent Thursday to Nasdaq, S&P Dow Jones Indices, FTSE Russell and Morningstar Indexes, Warren asked whether the firms made or considered rule changes after lobbying from Elon Musk, other SpaceX officials or representatives from OpenAI or Anthropic. She also requested any communications between the index companies and those firms. CNBC first reported the letter.

Warren pointed to changes or proposed changes that would fast-track newly listed stocks into top indexes.

"The changes to your index rules to accommodate these large companies, however, have the potential to destabilize markets and create significant risks for American investors, especially retirees and other individuals that rely on index funds for their savings," she wrote.

SpaceX is set to begin trading Friday. The offering is expected to be one of the largest in history, with the company valued around $1.8 trillion. OpenAI and Anthropic have also confidentially filed for IPOs.

Earlier this week, Warren called on the SEC to delay the SpaceX offering, arguing the agency had not done enough due diligence to protect investors and market integrity.

The letter adds to a growing regulatory spotlight on how index providers handle large, high-profile listings. Critics have argued that fast-track rules could expose passive funds to volatile stocks before they have a trading history, forcing retirees and other index-fund holders into positions they did not choose.