IBM's worst crash exposes earnings bubble hidden beneath AI boom

The IBM crash on July 14 arrives at a moment of sharp contradiction in financial markets. While JPMorgan and Goldman Sachs reported record profits—JPMorgan's $21.2 billion（約3.4兆円） net income the highest in U.S. banking history, Goldman's net earnings up 84% to $6.4 billion（約1兆円）—IBM's relatively modest 3.7% revenue miss triggered a historic sell-off. This juxtaposition has led economist Steve Hanke to articulate a thesis gaining traction among analysts: markets are mispricing not stocks' valuations but the earnings that justify those valuations.

The traditional AI bull case rests on two pillars: first, that leading AI companies like Nvidia and Alphabet generate real cash flow unlike profitless dot-com names, and second, that S&P 500 valuations sit at 22x forward earnings, below the 25x-plus threshold typically associated with bubble territory. BCA Research's Peter Berezin has argued for months that today's AI trade is "primarily an earnings bubble rather than a valuation bubble." The danger of such bubbles is their invisibility. Valuation bubbles announce themselves through stretched P/E ratios; earnings bubbles hide within reported profit figures that may be inflated by cyclical capex surges or easy credit. Analysts historically cut profit estimates only after stock declines have already begun, leaving investors without early warning. When earnings bubbles burst, they leave behind real excess capacity—data centers, chip fabs—rather than merely erasing paper gains.

IBM's own aftermath illustrates this detection lag. BofA and UBS trimmed earnings estimates only after the stock had already crashed 25%, with BofA cutting its price target from $330 to $280 and UBS lowering 2026 EPS forecasts while holding its $236 target. The Street's split response—BofA maintaining a Buy rating while HSBC downgraded to Reduce—suggests genuine uncertainty about whether IBM represents a sector-wide crack or an isolated execution miss. The answer will emerge across the rest of earnings season.