2026 is set to be a record-breaking year for initial public offerings (IPOs), following SpaceX’s launch in early June, and with both Anthropic and OpenAI set to follow in the coming months. While we don’t expect these IPOs to challenge US stock markets in the near term, we do think they highlight the importance, these days, of investing in private markets given that so much value now accumulates there.

Going public

The prospect of very large companies going public on the US stock market has raised investor concerns about whether there is sufficient demand for this additional supply of new shares, or whether these IPOs will ‘crowd out’ interest in other stocks. However, there are three reasons why we don’t expect the behaviour of US stocks to be negatively impacted over the remainder of 2026.

First, despite a combined valuation of more than USD 4,000 billion, the inclusion of SpaceX, OpenAI and Anthropic in major equity market indices will be a gradual process. Most major equity market indices are weighted by the value of a company’s shares that are available for trading by the public. In other words, the free float, not the total market capitalisation. SpaceX, for example, only floated around 4% of its shares in its June debut. See Exhibit 1 for an illustration of the potential weight of the mega-cap debutants in the S&P 500.

While the free float share of this year’s major IPOs will rise over time, there are rules in place that limit how quickly this can happen. Before a company goes public, ownership is typically split across the company’s founders, employees and early-stage investors. To avoid a flood of supply immediately after a company lists, these “owners” are often not allowed to sell any of their stakes until 90 to 180 days after IPO, known as a lock-up period. Looking at the 10 largest IPOs between 2010 and 2025, the average free float on day one was around 45%, which then rose to around 80% six months later, according to data from J.P. Morgan Research.

It’s also worth remembering that newly listed companies don’t automatically get included in all benchmarks from day one. Some index providers, such as FTSE, MSCI and Nasdaq, have created “fast-entry” rules that will now see mega-cap companies joining major benchmarks after just a handful of trading days. S&P Global, however, will continue to require companies to have traded for 12 months before they can be considered eligible for inclusion in the S&P 500.

The second thing to bear in mind is the incentives created by the “circular financed” nature of companies in the tech ecosystem. The complex nature of financing agreements that span the artificial intelligence (AI) landscape has created a huge number of interdependencies, with many of the largest companies taking stakes in other players. The incentives for all companies in the tech ecosystem to see these IPOs progress smoothly are clear.

And finally, we must also recognise that the big question about technology stock valuations is whether the tech companies will generate a return on their investment. As we discuss in our 2026 Mid-Year Investment Outlook, the answer depends on whether companies outside of tech are managing to improve their productivity and profitability. However, while quarterly reporting requirements will result in far greater transparency around the prospects for future profitability, this question is still likely to remain unanswered for some time. We already know that this year’s market debutants all have grand ambitions for their role in an AI-driven future, but it’s unlikely that early earnings releases will do much to sway investors’ belief about how these companies will evolve over the coming decade in either direction.

You’ve got to be in it to win it

While the immediate impact on the US stock market is not expected to be significant, there is a lesson to be learned from these IPOs: the need for exposure to private markets in a modern portfolio.

SpaceX was founded in 2004 and therefore remained a private company for 22 years before coming to market at a valuation of USD 1,770 billion. Its value has since risen to over USD 2,000 billion, briefly surpassing the market capitalisation of Amazon.

The contrast with many of today's largest public companies is striking. Amazon listed in 1997 at the age of three with annual revenues of approximately USD 0.3 billion and a valuation of less than USD 1 billion in today's dollars. Google went public after six years with revenues of almost USD 4.8 billion and a valuation of roughly USD 40 billion. Meta listed after eight years with revenues of USD 5.4 billion and a valuation of around USD 151 billion. SpaceX listed after 22 years with revenues of USD 18 billion and a valuation of USD 1,770 billion. This was more than 40 times larger than Google's IPO, nearly 12 times larger than Meta's, and almost 2,000 times larger than Amazon's (see Exhibit 2).

While SpaceX represents an extreme example, the trend extends well beyond one company. In the technology boom of the late 1990s, the median technology company came to market at less than six years old. That figure has since doubled to 12 years. Companies are not only staying private for longer, but they are also arriving at public markets at a fundamentally different stage of maturity (see Exhibit 3).

This greater maturity can be seen clearly in annual revenues (see Exhibit 4). Today, the median technology company generates almost three times the annual revenue at IPO compared to a typical company that listed in the 1990s, when median revenues remained below USD 50 million in today’s money. The typical company coming to market is no longer a young, fast-growing business in its early stages, but an established company that has already done much of its scaling while remaining private.

The implication is clear. Companies are staying private much longer and enjoying significant growth before they become available to investors that focus solely on public markets.

Again, the trend extends beyond SpaceX. The expansion of private capital over the past two decades has fundamentally changed the financing options available for ambitious companies. Take Anthropic as an example. In May 2026 it raised USD 65 billion in a late-stage “Series H” financing round, valuing the company at USD 965 billion. Companies can now raise the capital they need to scale without ever accessing public markets. As a result, a growing share of the most dynamic value creation in the economy is taking place in private markets, before public investors can participate.

The changing composition of markets reflects this trend to stay private for longer, with a 2023 report from Bain & Company citing that 86% of companies with revenues above USD 100 million in the US were still private. Public equity markets, for all their depth and liquidity, now have almost 30% fewer companies than they did in the late 1990s. The companies that may well define the next decade of economic growth may follow SpaceX's path – scaling to extraordinary size in private markets before, or instead of, going public.

The lesson is clear: accessing the full breadth of economic growth today, and participating in value creation from its earliest stages, increasingly requires exposure to both public and private markets.