U.S. IPO market surges past $115.6 billion（約18兆円） in first half of 2026, broadening beyond mega-deals

The U.S. IPO market is experiencing a resurgence after years of volatility, with the first half of 2026 establishing a historic foundation. SpaceX's June 12 listing set a record as the largest IPO in financial market history at $86 billion（約14兆円）, and even excluding that outsized transaction, the quarter would have ranked as the strongest U.S. IPO period since 2021, according to Renaissance Capital. This performance reflects convergent tailwinds: across industrial markets, AI adoption is accelerating, defense spending is increasing, and private capital continues funding category-leading companies at high valuations.

The significance of the current moment lies not in the mega-deals themselves but in what comes next. EY and General Atlantic both point to a rebalancing underway in the second half of 2026. Where the first half concentrated capital and investor attention on a handful of crowded trades—chiefly AI, semiconductors, and space—strategists expect mid-cap and overlooked sectors to emerge as discounts narrow toward normal levels. Advanced manufacturing, defense, energy, and AI infrastructure are named as areas poised to attract fresh investor interest. This broadening suggests that the IPO market is transitioning from a capital-concentration phase (dominated by mega-cap trades that drew outsized media attention) into a more balanced calendar where gains from early mega-deals are redeployed into less crowded opportunities.

The pipeline of anticipated late-2026 and 2027 listings—including Anthropic (reportedly eyeing a $1 trillion（約160兆円） valuation), several crypto and fintech candidates, and OpenAI—indicates that market momentum is likely to persist. However, the sustainability of this rebalancing depends on whether current pipelines convert and market conditions remain supportive, as EY notes. The test for the rest of 2026 will be whether investor appetite for growth and infrastructure across these less-crowded sectors proves genuine or whether capital gravitates back toward familiar mega-cap narratives.