The upcoming SpaceX IPO is raising concerns among some investors that the offering will simply be too large for the market to absorb in a healthy way.

The market debut on Friday, set to be the largest in history, is more than four times oversubscribed, Bloomberg reported.

Stocks fell last week as analysts speculated investors were selling shares to make space for the SpaceX IPO and other big upcoming tech listings, namely OpenAI and Anthropic, the Financial Times wrote. “Record new issues is one of the classic signs of a bubble,” one investment executive said.

US Sen. Elizabeth Warren this week called for regulators to delay the IPO, citing SpaceX’s historic valuation among other concerns.