Comment by tristanj
17 hours ago
> Anthropic, OpenAI and SpaceX could well amount to $4T+ in market cap. That's ~6% of the entire index. It's like adding another NVidia.
This is a common misconception. The S&P 500 weights allocation by float-adjusted market cap, not by total market cap. In the case of SpaceX, they are planning to float ~4% of shares at IPO. Even if SpaceX was added to the index, its index weight would be based on that tiny float, and at a $1.75T valuation it would be treated as roughly a $70 billion company.
SpaceX weight would be ~0.125% of the index, not ~2.5% as you imply.
Nasdaq "solved" that problem by including a 5x float multiplier for stocks with less than 20% of shares available to the public...
That's misleading.
Before the changes, the Nasdaq-100 index was total market cap-weighted not float-weighted. Once a company crossed 10% floated shares, the company was added to the index at full weight.
Nasdaq's new system is a hybrid of float-weighted and cap-weighted. If a company has below 33.3% float, its weighting is 3x float. Above that, it's cap weighted. This allows a gradual fade-in of the company into the index.
It's a better system than the previous one, and in Nasdaq's own words, more conservative.
For the Nasdaq-100, SpaceX at 4% float gets 3 x 4% = 12% of its market cap counted, which is $210B not $1.75T. Still <1% of the index.
Also, the multiplier is 3x, not 5x. Nasdaq proposed 5x, but after feedback, this was reduced to 3x. The new thresholds are 3x and 33%, not 5x and 20%.
https://www.nasdaq.com/newsroom/nasdaq100-index-methodology-...
I stand corrected, I was not aware of the full mechanism, and I was still stuck at the proposed multiplier and not the actual one.
SoaceX plans to continually unlock float for the first six months of being listed. So the percentage of the index would continue to rise.