SpaceX, Amazon-backed (AMZN) Anthropic, and Microsoft-backed (MSFT) OpenAI's upcoming initial public offerings may drag down broader stock markets by drawing tens of billions away from existing companies, Research Affiliates founder Rob Arnott was quoted as saying by Bloomberg News on Friday.

"It's going to disrupt the capital markets, and it already is disrupting the capital markets," Arnott said in an interview with Bloomberg.

Index funds will have to trim their current positions to make room for new entrants that could squeeze out the larger smaller firms, the report said.

(Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)