Nasdaq Eases Index Entry Rules for OpenAI and Anthropic IPO Wave as S&P Holds Firm

Major companies including OpenAI, Anthropic and SpaceX are preparing to go public, and traditional waiting periods could prevent indexes from promptly reflecting the market. But adding newly listed companies too soon would force passive funds tracking those indexes to buy shares and could drive up stocks before they are fully priced. Nasdaq therefore revised its Nasdaq-100 rules effective May 1, 2026.

Under the new rules, a newly listed company large enough to rank among the Nasdaq-100’s top 40 by market capitalization can join the index after 15 trading days, sharply reducing the previous minimum wait of three months. S&P Dow Jones Indices, however, decided on June 4, 2026, not to shorten the S&P 500 waiting period from 12 months to six months, meaning SpaceX would still have to wait a year. Its inclusion is estimated to trigger about $14 billion in passive buying.