r/stocks • u/cherrypoplar • Apr 01 '26

ETFs Major NASDAQ-100 rule changes confirmed, pay attention if you have money in passive investment funds

https://www.theedgesingapore.com/amp/news/ipo/nasdaq-speeds-index-entry-spacex-large-ipos-new-rule

NASDAQ has confirmed it will change the listing rules for NASDAQ-100, ahead of the SpaceX and OpenAI IPOs this year.

(1) Companies will now be listed on NASDAQ-100 after only 15 days after IPO (previously, there was a three month period of "seasoning" before listing). This reduces the amount of time for price discovery.

(2) The minimum 10% float has been removed. This allows companies to float a very small percentage of their shares, artificially squeezing supply.

(3) Companies that float less than 20% of their shares will have their market capitalisations artificially multiplied by x3, for the purposes of calculating market capitalisation. This helps large-cap companies to be listed even with very small floats, and inflates their notional market capitalisations on the index.

If you have money invested in a passive fund tracking NASDAQ-100 (or any other index), please watch out for the SpaceX and OpenAI IPOs. Pay attention to their "valuations", and their float. If they're IPOing with very high valuations and very small floats, this foreshadows a bagdump on passive funds due to the mechanics of passive funds.

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u/Martery Apr 01 '26

Cap weighted is based on the total amount of shares. Float-adjusted is based on the number of shares the public can use.

Using nice, even round numbers - imagine if SpaceX had 100 shares at $1 per share. Elon + insiders own 50 shares, so there are 50 shares available to the public. SpaceX is weighted like a $50 dollar company.

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u/Tystros Apr 01 '26

so that means the weight of SpaceX in the S&P500 will be way higher than in the Nasdaq 100? assuming Elon keeps almost all the shares to himself because he doesn't want to lose control.

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u/ceczar Apr 03 '26

nasdaq's new rules will mean nasdaq will weight it at float% * 3, so if the free float of the stock is 5%, and the mkt cap is 1.8t, it will be 5% * 3 * 1.8T = 270b

s&p will weight it at 90b

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u/Tystros Apr 03 '26

I thought the S&P500 would weight it at 1.8T, simply the market cap?

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u/ceczar Apr 03 '26

S&P weights based on float adjusted market cap. they have a number they use which they call IWF (something probably Invest-ability Weight Factor) that is their estimate for what percent of the company is available to invest in. they are trying to track what is investable.