No tracker publishes one operating system market share figure for banks. The published data sits in layers: Kyndryl’s banking survey for mainframe core systems, Microsoft lifecycle dates for ATM software, StatCounter pageview shares for mobile channels and FINOS survey data for open source.
This guide covers operating system market share in banking and finance across those layers, using releases from December 2024 to September 2026.
Operating System Market Share In Banking And Finance
Does Any Tracker Publish Operating System Market Share for Banks?
No. StatCounter, IBM, Microsoft, Kyndryl, BMC and FINOS each measure one slice, and none of them publishes a combined operating system share for banks.
Core systems sit on mainframes, where Kyndryl’s 2025 survey gives the only bank-specific figures used here. Those figures are shares of survey respondents, not install counts.
ATMs run Windows IoT editions. Hyosung Americas told Digital Transactions in December 2024 that Windows 10 LTSB 2016 is the version commonly used on U.S. ATMs, but no vendor in this review publishes an ATM operating system share.
Server-side Linux appears in open source surveys such as FINOS. Sector splits for servers are covered in this breakdown of Linux server share by industry.
Mobile channels map to Android and iOS. StatCounter measures sampled web pageviews across all tracked sites, not banking apps.
58% Grew Mainframe Use: Kyndryl’s 2025 Banking Survey
Kyndryl’s 2025 banking edition shows 58% of banking and financial services respondents increased mainframe use over the prior 12 months. Another 33% held usage steady and 9% cut it.
Kyndryl commissioned Coleman Parkes Research to survey 500 senior leaders at mainframe-using enterprises. The banking PDF does not state how many of the 500 work at banks.
| Finding (share of respondents) | Banking & financial services | All industries |
|---|---|---|
| Modernization strategy shifted in last 12 months | 76% | 80% |
| Mainframe very or extremely important to strategy and operations | 80% | 78% |
| Struggle to find skilled talent for modernization | 67% | 70% |
| Regulatory compliance influences modernization decisions | 99% | 94% |
Why Banking Firms Keep Workloads on the Mainframe
| Rank | Reason | Share of banking respondents |
|---|---|---|
| 1 | Business criticality of the data | 48% |
| 2 | Information security concerns | 29% |
| 3 | Access to AI technologies | 27% |
| 4 | Lower costs on the mainframe | 26% |
These shares overlap and do not add to a single whole. Banking respondents also rank security as the top factor in modernization strategy.
Banking and Finance Operating System Strategy by Modernization Path
Modernizing on the mainframe leads among banking respondents at 47%, against 43% across all industries. Integrating with cloud sits at 26% in banking and 34% overall.
Moving applications off the mainframe to other platforms stands at 17% in banking and 16% overall. Kyndryl does not state whether respondents could name more than one path.
| Modernization path | Expected annual savings, banking & financial services |
|---|---|
| Modernizing on the mainframe | $35.5 million |
| Moving applications off the mainframe to other platforms | $31.1 million |
| Integrating with cloud | $27.2 million |
How Is AI Changing Bank Mainframe Operating Systems?
IBM z17 became generally available on June 18, 2025. IBM says its Telum II processor enables more than 450 billion inferencing operations a day with a one-millisecond response time.
IBM also states that z17 handles 50% more AI inference operations per day than z16. These are vendor capability figures, not measured bank deployments.
Among Kyndryl’s banking respondents, optimizing performance and resource allocation is the top AI mainframe use case at 30%, versus 33% across all industries. Fraud detection, security testing and threat detection complete the top four.
| AI and GenAI projection, next three years | Banking & financial services | All industries |
|---|---|---|
| Projected savings (labor, operational, business) | $24 million | $29 million |
| Estimated revenue | $27 million | $44 million |
IBM Z Revenue Fell 42% in Q2 2026
IBM Z revenue fell 42% year over year in the second quarter of 2026, according to IBM’s July 22, 2026 results. Infrastructure revenue dropped 7% to $3.8 billion.
IBM’s Form 10-Q links the decline to performance below expectations and a comparison against a strong prior-year z17 launch. In a July 14 letter, CEO Arvind Krishna said clients shifted late-June capex toward servers, storage and memory.
Distributed Infrastructure rose 37% in the same quarter, and IBM does not split that line by operating system. Wider enterprise figures sit in these Linux data center market statistics.
Mainframe Confidence Across Industries (BMC 2026)
BMC’s 2026 Mainframe Survey found 94% of respondents see the mainframe as a long-term platform or one attracting new workloads. The 2025 edition recorded 97%, the highest in the survey’s history.
The 2026 edition also reports 94% continuing to invest and 69% with growth in general-purpose capacity. BMC’s respondents span industries, so these are not bank-only figures.
ATM Operating System Market Share in Banking: The October 13, 2026 Cutoff
Windows 10 Enterprise 2016 LTSB and Windows 10 IoT Enterprise 2016 LTSB reach end of support on October 13, 2026, according to Microsoft. Microsoft opened Extended Security Updates for the 2016 LTSB on April 1, 2026, for up to three years.
Microsoft lists ATMs among the fixed-function devices built on Windows IoT Enterprise. No published source gives a share of ATMs by Windows version.
| Windows IoT Enterprise release | Start date | End of support |
|---|---|---|
| Windows 10 IoT Enterprise LTSC 2015 | Jul 29, 2015 | Oct 14, 2025 |
| Windows 10 IoT Enterprise LTSC 2016 (2016 LTSB) | Aug 2, 2016 | Oct 13, 2026 |
| Windows 10 IoT Enterprise LTSC 2019 | Nov 13, 2018 | Jan 9, 2029 |
| Windows 10 IoT Enterprise LTSC 2021 | Nov 16, 2021 | Jan 13, 2032 |
| Windows 11 IoT Enterprise LTSC 2024 | Oct 1, 2024 | Oct 10, 2034 |
Diebold Nixdorf says it made the first Windows 11 ATM installation, reported in December 2024 at two banks in Central Asia. The machines run Windows 11 IoT Enterprise LTSC 2024.
Windows 10 LTSB 2016 is the version commonly used on U.S. ATMs, according to William Budde of Hyosung Americas. Desktop Windows pageview shares by market are listed in this desktop OS share by country report.
Is Android or iOS Bigger for Mobile Banking Channels?
Android took 67.61% of worldwide mobile web pageviews in August 2026, per StatCounter. In the United States, iOS led at 60.68%.
StatCounter samples pageviews across its tracked sites, so these shares describe traffic, not banking app users or installed devices. Browser splits on the same traffic base appear in this web browser market share analysis.
| Mobile OS | Worldwide | United States |
|---|---|---|
| Android | 67.61% | 39.29% |
| iOS | 32.36% | 60.68% |
| KaiOS | 0.01% | 0.02% |
| Linux | 0.01% | 0% |
| Windows | 0.01% | 0% |
| Samsung | 0% | 0% |
Linux and Open Source in Banking and Finance: FINOS 2025 Findings
The FINOS 2025 State of Open Source in Financial Services report measures attitudes and practices among survey respondents, not operating system installs. Its figures describe those respondents, not all institutions.
| Finding | Share of respondents |
|---|---|
| Open source delivers business value | 87% |
| Vulnerabilities are the leading security concern | 52% |
| Industry standards are where collaboration delivers most value | 51% |
| AI named as most vital open source technology | 49% |
| Unclear ROI slows contribution | 48% |
| Legal or licensing concerns slow contribution | 48% |
| Actively produce SBOMs | 43% |
| Cloud named as most vital open source technology | 39% |
| Supply chain attacks cited as a concern | 37% |
AI has topped the FINOS list of vital open source technologies for three years running. Large-enterprise Linux use outside finance is tracked in these Linux adoption figures for Fortune 500 companies.
LinuxONE Emperor 5 for Linux on Z
IBM announced LinuxONE Emperor 5 on May 6, 2025, built on the same Telum II processor as z17. Canonical says the system supports up to 208 customer cores and up to 64TB of memory, with Ubuntu Server ready from day one.
Red Hat Enterprise Linux and SUSE are also among the distributions certified for the system, per Phoronix. Distribution shares on general servers are covered in this Linux distribution market share roundup.
FAQs
What operating system do banks use for core systems?
Kyndryl’s 2025 banking survey points to mainframes: 80% of banking respondents called the mainframe very or extremely important to operations, and 58% increased usage over the prior 12 months.
What operating system do ATMs run?
Many run Windows IoT Enterprise. Hyosung Americas says Windows 10 LTSB 2016 is commonly used on U.S. ATMs; its support ends October 13, 2026. Windows 11 IoT Enterprise LTSC 2024 runs to October 10, 2034.
Is Android or iOS more common for mobile banking?
StatCounter does not track banking apps. Across all mobile web pageviews in August 2026, Android led worldwide at 67.61%, while iOS led the United States at 60.68%.
Are banks moving off the mainframe?
A minority are. Kyndryl’s 2025 banking edition shows 17% moving applications off the mainframe, against 47% modernizing on it. Only 9% reported lower mainframe use over the prior 12 months.
Does Reddit show which operating systems banks run?
Reddit threads offer individual accounts, not measured data. For measured figures, use Kyndryl’s banking survey, Microsoft lifecycle dates and StatCounter pageview shares, each with its stated period.
Sources
https://www.kyndryl.com/content/dam/kyndrylprogram/doc/en/2025/mainframe-modernization-banking.pdf
https://newsroom.ibm.com/2026-07-22-IBM-RELEASES-SECOND-QUARTER-RESULTS
