S&P Dow Jones Indices just told the biggest IPO candidates in history to wait their turn. On June 4, the index provider confirmed it will not change its eligibility rules for major US indices, including the S&P 500, after a formal consultation period that gathered input from a wide range of market participants.
The decision lands at a particularly loaded moment. SpaceX is planning a June 2026 IPO with a target valuation of $1.75 trillion, offering less than 5% of shares initially. Under the existing rules, Elon Musk’s rocket company would face at least a one-year wait before even being considered for the S&P 500, regardless of how massive it is at listing.
What the rules actually require
The S&P 500 isn’t just a list of America’s biggest companies. It’s a curated index with specific gatekeeping criteria, and S&P just reaffirmed every single one of them.
First, there’s the 12-month seasoning period. A company must trade publicly for a full year before it’s eligible. No exceptions for trillion-dollar valuations.
