⚠ IBM Reports the Swing, Not the SizeLow threat

IBM (IBM) — threat to the moat

IBM tells investors how fast the mainframe grows but not how big it is, and the 14 July fall is part of the price of that secrecy.

IBM publishes the growth rate of IBM Z every quarter and never the revenue. The filings say it rose 51.7% in 20251 and fell 42.0% in the second quarter of 20262, but the dollar figure sits inside Hybrid Infrastructure, $10,618 million in 20253, alongside Power and Storage.

Hybrid Infrastructure revenue ($M)8,16720219,45120229,21520238,913202410,6182025IBM Annual Reports 2022-2025; IBM Z inside, not disclosed
The only dollar figure that contains the mainframe.

That opacity is a threat to the owners rather than the business. Investors pricing a franchise need to know its size. Without it, a 42% fall reads as a catastrophe or a blip depending on assumptions, which may be why a quarter with revenue up 1%4 produced the worst day in the stock's recorded history5.

The consequences have been concrete. Hagens Berman, a law firm, announced in September 2026 that it was investigating possible securities-law violations after the fall, citing "serious problems in the company's Z performance"6. An investigation is not a lawsuit, but it is the cost of surprises.

The first-quarter release shows how the disclosure can mislead in the other direction too. It reported IBM Z up 51%7, and total revenue of $15.9 billion, up 9 percent8. An investor who could not see the dollar value of the mainframe could not tell how much of that growth was one product's launch year. Three months later the same line fell 42.0%9. A franchise disclosed only as a growth rate is a franchise that surprises.

This threat is low for the moat and moderate for the shares. It would ease if IBM began disclosing IBM Z revenue in dollars; it would worsen if another quarter swung this far against guidance, because each surprise lowers the multiple the market is willing to pay.

References
  1. ReportedThe filings say it rose 51.7% in 2025 and fell 42.0% in the second quarter of 2026, but the dollar figure sits inside Hybrid Infrastructure, $10,618 million in 2025, alongside Power and Storage.
    IBM 2025 Annual Report (Form 10-K exhibit) - management discussion, consolidated financial statements and notes - management discussion of the Infrastructure and Financing segments: IBM Z, Hybrid Infrastructure and support. — FY2025 · publ. 24 February 2026 · source ↗
  2. ReportedThe filings say it rose 51.7% in 2025 and fell 42.0% in the second quarter of 2026, but the dollar figure sits inside Hybrid Infrastructure, $10,618 million in 2025, alongside Power and Storage.
    IBM Form 10-Q for the quarter ended 30 June 2026 - segment results, revenue categories, RPO, the Confluent acquisition and management discussion - Infrastructure and Financing segment results. — Q2 2026 · publ. 23 July 2026 · source ↗
  3. ReportedThe filings say it rose 51.7% in 2025 and fell 42.0% in the second quarter of 2026, but the dollar figure sits inside Hybrid Infrastructure, $10,618 million in 2025, alongside Power and Storage.
    IBM 2025 Annual Report (Form 10-K exhibit) - management discussion, consolidated financial statements and notes - management discussion of the Infrastructure and Financing segments: IBM Z, Hybrid Infrastructure and support. — FY2025 · publ. 24 February 2026 · source ↗
  4. ReportedWithout it, a 42% fall reads as a catastrophe or a blip depending on assumptions, which may be why a quarter with revenue up 1% produced the worst day in the stock's recorded history.
    Arvind Krishna's letter to IBM investors with preliminary second-quarter 2026 results, Form 8-K exhibit 99.1. — Q2 2026 · publ. 14 July 2026 · source ↗
  5. ReportedWithout it, a 42% fall reads as a catastrophe or a blip depending on assumptions, which may be why a quarter with revenue up 1% produced the worst day in the stock's recorded history.
    CNBC, IBM stock craters 25%, the worst day on record, after company issues second-quarter earnings warning. — July 2026 · publ. 14 July 2026 · source ↗
  6. ReportedHagens Berman, a law firm, announced in September 2026 that it was investigating possible securities-law violations after the fall, citing "serious problems in the company's Z performance".
    GlobeNewswire, Hagens Berman announces investigation of IBM after the 14 July 2026 fall. — September 2026 · publ. 23 September 2026 · source ↗
  7. ReportedIt reported IBM Z up 51%, and total revenue of $15.9 billion, up 9 percent.
    IBM first-quarter 2026 results release, Form 8-K exhibit 99.1 - IBM Z growth and the 31st consecutive annual dividend increase. — Q1 2026 · publ. 22 April 2026 · source ↗
  8. ReportedIt reported IBM Z up 51%, and total revenue of $15.9 billion, up 9 percent.
    IBM first-quarter 2026 results release, Form 8-K exhibit 99.1 - IBM Z growth and the 31st consecutive annual dividend increase. — Q1 2026 · publ. 22 April 2026 · source ↗
  9. ReportedThree months later the same line fell 42.0%.
    IBM Form 10-Q for the quarter ended 30 June 2026 - segment results, revenue categories, RPO, the Confluent acquisition and management discussion - income statement, segment table, RPO, pensions and working capital. — Q2 2026 · publ. 23 July 2026 · source ↗
Sources
Generated September 28, 2026