The IBM mainframe business decline at the heart of Big Blue’s second-quarter earnings wiped out roughly $67 billion in stock market value in a single session, according to The Wall Street Journal, triggering one of the most bruising days in the company’s 115-year history.
The quarter’s headline numbers were, on their own terms, respectable. IBM posted $17.2 billion in revenue, $9,977 million in GAAP gross profit, and a GAAP gross margin of 58.8%, up 1.1 points year on year, according to Arvind Krishna’s letter to IBM investors. Net earnings came in at $2.2 billion. None of that was the problem.
The problem was infrastructure. Mainframe hardware revenue fell 42%, dragging results so far below Wall Street’s expectations that Krishna and the board took the unusual step of pre-announcing the miss before formal earnings were released. Krishna’s published letter described results that were ‘worse than our expectations,’ offering investors a preview of the damage. The stock fell 25%, its biggest single-day decline on record.
Why the IBM Mainframe Business Decline Cascades Through the Whole Company
The mainframe is not simply one product line among many. Chief financial officer Jim Kavanaugh laid out the arithmetic on the investor call: IBM earns $3 in software revenue for every $1 of mainframe hardware sold. That ratio means a hardware shortfall compounds rapidly across the income statement.
Kavanaugh confirmed to Bloomberg that annual software growth would now come in at 6% to 8%, down from a prior target of more than 10%. Full-year constant-currency revenue growth guidance was cut to a 4% to 5% range from the earlier forecast of more than 5%. Both reductions were attributed entirely to the infrastructure weakness and its associated software pull-through.
Krishna’s explanation for the shortfall was specific. ‘Tens’ of customers that had been expected to take delivery of a new mainframe during the quarter chose not to. Mainframes carry price tags running from hundreds of thousands to millions of dollars, with maintenance contracts and software stacking millions more on top. A deferral of that scale moves the needle quickly.
AI Built the Problem and, Krishna Insists, Will Not Bury the Mainframe
The source of the deferral, Krishna argued, was the same AI infrastructure boom that had been lifting IBM’s share price. Enterprise hardware costs, driven by surging demand for data centre components, rose 15% to 30%. Customers caught in that pricing squeeze reallocated capital to the more immediately urgent purchases. ‘When they were faced with that issue, then they decided to move budget to those areas where they were having that extreme price,’ Krishna said.
Dell and HP have both warned publicly that AI-driven demand for components such as memory has forced price increases on enterprise gear. Apple has flagged similar pressures. The dynamic is broad, but its effect on IBM’s most lucrative product line was acute.
Krishna insisted the deferred purchases are not lost, merely delayed. Several customers, he said, have already placed orders in the current quarter. ‘We see no evidence of clients moving off the mainframe,’ he said. The argument is that the hardware cycle will complete; the software contracts will follow.
There is reason to take that argument seriously, even if investors did not on the day. IBM entered 2026 on the back of a strong prior year: its 2025 Annual Report filed with the SEC showed full-year revenue of $67.5 billion, up 6% at constant currency, with free cash flow of $14.7 billion, described as its highest in over a decade. The company’s generative AI book of business stood at more than $12.5 billion since inception to date, and software revenue grew at what the company called its highest annual growth rate in history.
That momentum was built, in part, on tens of billions spent remaking IBM as a software company through acquisitions including Red Hat, HashiCorp, and Confluent, with further investment into AI-powered enterprise security alongside OpenAI.
The tech industry has been predicting the death of the mainframe for decades. Each time, the machine has outlasted its obituary. The more pointed question now is whether the current quarter proves Krishna right about deferral, or wrong about the permanence of the shift. IBM’s next earnings update will answer it.
