⚠ Fifteen Percent Is Not GrowingLow threat

IBM (IBM) — threat to the moat

If 85% of mainframe capacity is holding, 15% is not, and IBM does not say how fast it is leaving.

If clients holding 85% of installed capacity are maintaining or growing it1, clients holding the other 15% are not. IBM does not say how fast that slice is shrinking or why.

Infrastructure Support revenue ($M)6,02120215,83720225,37720235,10720245,1002025IBM Annual Reports 2022-2025
Down about 15% in four years.

That slice matters because mainframe economics are cumulative. Every client that moves a workload off the platform reduces the capacity on which Transaction Processing licences, infrastructure support and financing are all priced. The support line already shows the slow erosion: Infrastructure Support revenue was $6,021 million in 2021 and $5,100 million in 202523, about 15% lower4.

Competition for the workloads is real. IBM's own filing says "cloud service providers are leveraging innovation in technology" in its infrastructure markets5. A migration off a mainframe takes years, but once finished it does not come back.

The installed base also appears in the Financing segment, which leases machines to clients. When leases end, IBM takes the equipment back, and in 2025 its Financing profit was lifted by "sales of returned leased equipment to Infrastructure"6. Returned machines are a normal part of the cycle, but they are also the physical trace of clients who did not renew a lease. IBM does not say how many machines come back and are not replaced.

The threat is low while IBM keeps disclosing a high figure. It rises if the share of capacity kept or grown is reported lower at the next launch, or if support revenue, which tracks the installed base, falls more than 3% in a single year; it fell 0.1% in 20257.

References
  1. ReportedIf clients holding 85% of installed capacity are maintaining or growing it, clients holding the other 15% are not.
    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 ↗
  2. ReportedThe support line already shows the slow erosion: Infrastructure Support revenue was $6,021 million in 2021 and $5,100 million in 2025, about 15% lower.
    IBM 2022 Annual Report (Form 10-K exhibit 13) - zSystems growth, incremental sales to Kyndryl, disposal of the retained Kyndryl stake, Red Hat growth, 2021-2022 segment revenue. — FY2022 · publ. February 2023 · source ↗
  3. ReportedThe support line already shows the slow erosion: Infrastructure Support revenue was $6,021 million in 2021 and $5,100 million in 2025, about 15% lower.
    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. Moat Explorer calcThe support line already shows the slow erosion: Infrastructure Support revenue was $6,021 million in 2021 and $5,100 million in 2025, about 15% lower.
    Moat Explorer calculation from IBM's reported figures ($ millions unless stated). Segment mix 2025: Software 29,962 / 67,472 = 44.4% of segment revenue and 9,920 / 16,364 = 60.6% of segment profit; Consulting 21,055 / 67,472 = 31.2% and 2,464 / 16,364 = 15.1%; Infrastructure 15,718 / 67,472 = 23.3% and 3,458 / 16,364 = 21.1%; Financing 737 / 67,472 = 1.1% and 521 / 16,364 = 3.2%. Segment revenue below reported revenue: 60,530 - 59,621 = 909 (2022); 61,860 - 61,229 = 631 (2023); 62,753 - 62,510 = 243 (2024); 67,535 - 67,472 = 63 (2025). Growth: revenue 67,535 / 62,753 - 1 = 7.6% (2025); 62,753 / 61,860 - 1 = 1.4% (2024); Q2 2026 17,162 / 16,977 - 1 = 1.1%; Software 25,011 / 23,629 - 1 = 5.8%, 27,085 / 25,011 - 1 = 8.3%, 29,962 / 27,085 - 1 = 10.6%; Software Q2 2026 7,761 / 7,387 - 1 = 5.1%; Consulting 20,884 / 20,058 - 1 = 4.1%, 20,692 / 20,884 - 1 = -0.9%, 21,055 / 20,692 - 1 = 1.8%, 21,055 / 20,058 - 1 = 5.0% over three years, Q2 2026 5,327 / 5,314 - 1 = 0.2%; Infrastructure 14,593 / 15,288 - 1 = -4.5%, 14,020 / 14,593 - 1 = -3.9%, 15,718 / 14,020 - 1 = 12.1%, Q2 2026 3,835 / 4,142 - 1 = -7.4%; Financing 737 / 713 - 1 = 3.4%, Q2 2026 186 / 166 - 1 = 12.0%; Transaction Processing 8,603 / 7,714 - 1 = 11.5% and 8,603 - 7,714 = 889 added 2023-2025; Hybrid Cloud 7,327 - 5,827 = 1,500 added 2023-2025; 11% to 13% of 7,327 = 806 to 952 a year; OpenShift 30% x 2.0bn = 0.6bn a year; Infrastructure Support 5,100 / 6,021 - 1 = -15.3% (2021-2025) and 4,800 / 5,100 - 1 = -5.9%; research and development 8,316 / 7,479 - 1 = 11.2%; Software segment profit 9,920 / 7,012 - 1 = 41.5%; Consulting segment profit 2,464 / 1,871 - 1 = 31.7%; financing receivables 15,193 / 11,738 - 1 = 29.4%; total debt 62.0bn - 50.9bn = 11.1bn since 2022. Shares: mainframe-linked revenue 10,618 + 8,603 + 5,100 = 24,321, and 24,321 / 67,535 = 36.0%; Hybrid Cloud 7,327 / 29,962 = 24.5% of Software; OpenShift 2.0 / 24.6 = 8.1% of software ARR; June 2026 ARR 24.6bn / 2025 Software revenue 29.962bn = 82.1%; revenue outside the United States 40,643 / 67,535 = 60.2%, so about 60%; research and development 8,316 / 67,535 = 12.3% of revenue; quantum more than 10bn / 5 years = more than 2bn a year, and 2.0 / 8.316 = 24%, about a quarter; goodwill 67,717 / 151,880 = 44.6% of total assets; goodwill plus intangibles (67,717 + 11,391) / 151,880 = 52.1%; other assets 151,880 - 67,717 - 11,391 = 72,772; HashiCorp goodwill 4,684 / 7,433 = 63.0%; Confluent goodwill 7,238 / 11,602 = 62.4%, other net assets 11,602 - 7,238 = 4,364; stock-based compensation 1,685 / 16,364 = 10.3% of segment profit; Kyndryl spin 55,179 / 73,620 - 1 = -25.0% of 2020 revenue, about a quarter. Margins: Software Q2 2025 2,296 / 7,387 = 31.1%; Consulting Q2 2025 562 / 5,314 = 10.6%; Infrastructure Q2 2026 835 / 3,835 = 21.8% and Q2 2025 965 / 4,142 = 23.3%; total segment profit Q2 2026 4,092 / 17,110 = 23.9% and Q2 2025 4,003 / 17,009 = 23.5%; Financing Q2 2026 108 / 186 = 58% (reported 58.0%); pre-tax margin 10,328 / 67,535 = 15.3%; Global Technology Services 2020 117 / 27,039 = 0.4%; gross margin Q2 2026 9,907 / 17,162 = 57.7% and Q2 2025 9,977 / 16,977 = 58.8%. Red Hat: 7,327 / 35,100 = 20.9% of consideration; pre-tax at the Software margin 0.331 x 7,327 = 2,425, and 2,425 / 35,100 = 6.9%, about 7%; after a 21% tax 6.9% x 0.79 = 5.5%; revenue needed for 8% after tax 0.08 x 35,100 / (0.331 x 0.79) = 10,738, about 10.7bn, which is 10,738 / 7,327 = 1.47 times 2025 revenue: about 3.2 years at 12.5% growth, 4.4 years at 9% and 7.8 years at 5%. Cash and capital: acquisitions plus dividends 2025 8,294 + 6,255 = 14,549, and 14,549 / 14,734 = 98.7% of free cash flow; first half 2026 acquisitions 10.5bn / free cash flow 4.8bn = 2.2 times; dividends 6,255 / 10,593 = 59.0% of net income; Consulting backlog 31.9bn / 21.055bn = 1.5 years of revenue; remaining performance obligations 71bn - 68bn = 3bn lower in six months; pension risk transfers 16 + 6 + 1.2 = 23.2bn; defined-benefit obligations 14,460 + 29,872 = 44,332 against plan assets 18,073 + 26,733 = 44,806; free cash flow guidance 14.7bn + 1.0bn = 15.7bn. Further: revenue per employee 67,535 / 264.3 thousand = about 255,500 dollars; Q2 2026 Software share of segment profit 2,502 / 4,092 = 61.1%; first-half Software 14,813 / 13,722 - 1 = 8.0%; amortisation of acquired intangibles 2,166 / 1,627 - 1 = 33.1%; free cash flow 14.7 / 6.5 = 2.3 times (2021-2025); Q2 2026 Transaction Processing 2,208 - 2,030 = 178 lower, Data 1,782 - 1,499 = 283 higher, Hybrid Cloud 1,998 - 1,796 = 202 higher, Transaction Processing above Hybrid Cloud by 2,030 - 1,998 = 32; share price 225.51 / 332.46 - 1 = -32.2% from the 52-week high; first half 2026 Hybrid Cloud 3,903 / 3,483 - 1 = 12.1%, Transaction Processing 3,963 / 4,037 - 1 = -1.8%, Hybrid Infrastructure 4,678 / 4,512 - 1 = 3.7%, Infrastructure Support 2,483 / 2,515 - 1 = -1.3%, Automation 3,692 / 3,467 - 1 = 6.5%, Data 3,256 / 2,736 - 1 = 19.0%, Financing 406 / 357 - 1 = 13.7%, Strategy and Technology 5,829 / 5,702 - 1 = 2.2%, Intelligent Operations 4,770 / 4,680 - 1 = 1.9%; Strategy and Technology Q2 2026 2,933 / 2,920 - 1 = 0.4%; Infrastructure Support 2021 share 6,021 / 14,188 = 42.4%; Infrastructure 2020 pre-tax margin 1,654 / 14,533 = 11.4%; Consulting 2020 pre-tax margin 1,034 / 16,257 = 6.4%; buybacks 2015-2019 4,609 + 3,502 + 4,340 + 4,443 + 1,361 = 18,255; Hybrid Cloud 7,327 / 67,535 = 10.8% of revenue, about a tenth; acquisitions 2023 to June 2026 5.1 + 3.3 + 8.3 + 10.5 = 27.2bn; HashiCorp net of acquired cash and securities 7,433 - 929 - 331 = 6,173; ARR 24.6 - 21.3 = 3.3bn from end-2024 to June 2026; net interest excluding Financing 1,312 / 984 - 1 = 33.3%; 2024 signings 25,103 / 20,692 = 1.21, about 21% above revenue; generative AI book 12.5 - 9.5 = 3.0bn added in Q4 2025; EMEA growth gap 14.2 - 9.0 = 5.2 points; revenue 57,350 / 73,620 - 1 = -22.1% from 2020 as filed to 2021. Trailing twelve months to June 2026: revenue 67,535 - 31,519 + 33,079 = 69,095; net income 10,593 - 3,249 + 3,381 = 10,725; P/E 212,460 / 10,725 = 19.8; P/S 212,460 / 69,095 = 3.07 - growth rates and line totals. — FY2015-Q2 2026 · publ. September 2026 · source ↗
    Method: Arithmetic on figures reported in IBM's Annual Reports, Forms 10-Q, results releases and market data; operands shown in the source line.
  5. ReportedIBM's own filing says "cloud service providers are leveraging innovation in technology" in its infrastructure markets.
    IBM Form 10-K for 2025 - Item 1 business, competitors and strategic partners, Item 1A risk factors, executive officers. — FY2025 · publ. 24 February 2026 · source ↗
  6. ReportedWhen leases end, IBM takes the equipment back, and in 2025 its Financing profit was lifted by "sales of returned leased equipment to Infrastructure".
    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 ↗
  7. ReportedIt rises if the share of capacity kept or grown is reported lower at the next launch, or if support revenue, which tracks the installed base, falls more than 3% in a single year; it fell 0.1% in 2025.
    IBM 2025 Annual Report (Form 10-K exhibit) - management discussion, consolidated financial statements and notes - segment note: segment revenue, segment profit, margins and reconciliation to reported revenue. — FY2025 · publ. 24 February 2026 · source ↗
Sources
Generated September 28, 2026