Earlier quoted context omitted.
Very few 401ks offer the NASDAQ 100 as an investment option. Last I checked it was <1%.
Apparently the rule change also affects CRSP, which is the index behind Vanguard's Total Stock Market (VTI) index funds. https://finance.yahoo.com/markets/stocks/articles/spacex-ipo... VTI in turn is the primary holding of most of Vanguard's Target Date retirement funds, which are widely held in 401ks.
> CRSP indexes were also recently changed to better accommodate fast entry. New IPOs are eligible for CRSP's suite of indexes after five trading days, provided they pass the index's eligibility and investability screens. Previously, these screens included having at least 10% of shares qualifying as freely tradeable (known as float shares outstanding, or FSO). However, in April the methodology changed to allow stocks with either 10% FSO or approximately $3.3 billion in float-adjusted market capitalization to be eligible for index inclusion. The weighting of stocks in CRSP indexes is also based on free float, which should help address the investability challenges associated with thinly traded stocks.
* https://www.schwab.com/learn/story/some-indexes-accelerate-e...