The IPO window may be opening, but don't celebrate just yet. Three AI-focused companies—SpaceX, OpenAI and Anthropic—are set to absorb most of the available capital, with SpaceX pricing its massive offering at $1.77 trillion valuation. This concentration of listings suggests the reopening may be narrower than it appears.

SpaceX alone plans to raise $75 billion, exceeding the total U.S. IPO market volume for 2025. The company is allocating $22.5 billion to retail investors, who may need to sell existing holdings like Tesla and Bitcoin to participate. Meanwhile, Anthropic targets a $965 billion valuation and OpenAI eyes a fall listing. These three companies could constitute the entire 2026 IPO class.

The real impact lies in M&A activity. Once public, these companies become well-capitalized acquirers with liquid stock to deploy. OpenAI has already completed nearly half a dozen acquisitions this year, matching its full 2025 total. AI dealmaking surged 90% year-over-year in the first quarter.

Founders should focus on building companies that these AI giants want to acquire—real workflow ownership, proprietary data assets, or testing infrastructure. Investors must distinguish between a concentration event and genuine market reopening. The test comes this fall when follow-on listings emerge and we see how these newly public companies spend their stock.