Take SpaceX, for example. With an assumed valuation of USD 1.75 trillion, an IPO would be historic. Based on its full market capitalisation, the company would account for around 4.6% of the Nasdaq-100 and approximately 2.5% of the S&P 500, which would place it around 7th in both indices. At first glance, then, a new mega-cap. <\/p>\n\n
However, what matters is not the headline valuation, but the freely tradable float. As things stand, SpaceX brings only around USD 75 billion to the market. That would amount to just 4.3% of the assumed total valuation. This undermines the logic of the index. In the S&P 500, the free-float-adjusted weighting would be only around 0.11%, and in the Nasdaq-100 around 0.2%. A supposed index heavyweight would in fact be merely a medium-sized index constituent. <\/p>\n\n
Nvidia clearly stands out. The company dominates indices not only because of its market capitalisation, but also thanks to a free float of over 95%. Its market valuation therefore accounts for almost the entirety of its index weighting. With SpaceX, the situation would be the reverse. A high valuation alone does not necessarily result in a high index weighting. <\/p>\n\n
Inclusion in the index is also not guaranteed. The Russell 1000 requires a free float of at least 5%; at 4.3%, SpaceX would fall just short of this. The Nasdaq-100 amended its rules on 1 May 2026, removing the previous minimum requirement of 10%. The new limit is now three times the free float. Inclusion would be possible, but only with a reduced weighting. For the S&P 500, a committee makes the decision. There is no fixed minimum quota, but a substantial public free float is required. Whether 4.3% is sufficient remains to be seen. <\/p>\n\n
For active investors, the appeal lies in the timing. Index inclusions are unlikely to occur simultaneously. The Russell 1000 could react early, the Nasdaq 100 could follow later, and the S&P 500 not until the fourth quarter of 2026 at the earliest. Passive capital would therefore flow in waves rather than all at once. <\/p>\n\n
This is where the structural opportunity lies. Every time insider holdings are sold off, the free float increases. This also increases the free-float-adjusted index weighting. Every index review can trigger fresh mechanical demand as active funds adjust their positions to limit deviations from the benchmark index. <\/p>\n\n
What SpaceX exemplifies is likely to apply to potential IPOs by OpenAI or Anthropic as well: high valuations, high levels of insider ownership, and a low free float. The market focuses on the headline. Professional investors analyse the index mechanics. This is because the relevant capital flows do not necessarily arise at the time of the stock market debut, but rather in the rules, deadlines and weighting models that follow. <\/p>\n","protected":false},"excerpt":{"rendered":"
SpaceX, OpenAI and Anthropic could reshape the stock market landscape by 2026. But the real story lies less in the headlines about billion-dollar valuations than in the mechanics of the indices. <\/p>\n","protected":false},"author":5,"featured_media":1445950,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"ngg_post_thumbnail":0,"footnotes":""},"categories":[216,222],"tags":[],"class_list":["post-1446135","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-advertorial-en","category-trading-desk-en"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/posts\/1446135","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/comments?post=1446135"}],"version-history":[{"count":1,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/posts\/1446135\/revisions"}],"predecessor-version":[{"id":1446136,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/posts\/1446135\/revisions\/1446136"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/media\/1445950"}],"wp:attachment":[{"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/media?parent=1446135"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/categories?post=1446135"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.payoff.ch\/en\/wp-json\/wp\/v2\/tags?post=1446135"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}