Tech shares soar as mega-IPOs fuel bubble fears

Tech shares kept climbing as a frenzy around mega-IPOs pushed bubble fears back to the center of the market. SpaceX drew more than $250 billion of investor demand for a $75 billion offering, nearly four times the amount it sought to raise, while Japanese investors alone were willing to subscribe to more than 1 trillion yen, or $6.2 billion, of stock. The surge has turned a handful of marquee listings into a market signal investors cannot ignore.

OpenAI filed confidentially for an initial public offering on June 8, only a little more than a week after Anthropic filed to go public, intensifying a fast-moving race among artificial intelligence names. The concentration of demand around a small group of high-profile companies has fed the idea that capital is chasing the story rather than the balance sheet, especially after years of gains led by giant technology platforms.

Bank of America strategist Michael Hartnett said the planned mega-IPOs could lift technology’s weight in the S&P 500 from above 44% toward roughly 48%. That would take the sector into territory he argues would exceed prior bubble-era concentrations, a striking warning for an index already dependent on a narrow group of winners. For ordinary investors, the risk is not just whether these names can command rich prices, but whether the rest of the market is left exposed to an even more concentrated rally.

The comparison to the late-1990s dot-com boom is no accident. Then, as now, investors treated a new technology wave as an excuse to suspend valuation discipline, only to discover that enthusiasm had raced far ahead of fundamentals. Today’s mix of soaring AI optimism, record-sized IPO demand and a market already tilted toward mega-cap tech has revived that same uneasy feeling: the higher the shares climb, the more painful any reset could be.