The "total market index" point has been addressed twice now. Nobody ever claimed the S&P 500 tracks all equities. Only you keep bringing it up.

On your claim that these companies "wouldn't be in the top 20 by weight": as I addressed to you other times in this thread, SpaceX float 1 year after IPO would be 50%, giving it an index weight of $800 billion. That places it easily in the top 20 large-cap U.S. companies. The article linked has a chart of forecast free float. Your claim is false.

https://www.economist.com/finance-and-economics/2026/06/01/c...

On "arbitrary modification" of rules: every criterion in the index was itself added or revised at some point. The profitability requirement, the float threshold, the dual-class share exclusion then reinclusion. All these rules were modified. If all rule changes are "arbitrary," so are the existing rules. The only meaningful standard for evaluating a rule change is whether it better serves the index's stated purpose.

The stated purpose of the S&P500 is to be the "best single gauge of U.S. large-cap equities." A company with a $1.75T market cap that ranks in the top 5 by size in the US is, by definition, large-cap. Excluding such a large company is contrary to the stated purpose of the index.