A breakdown of the 1.9K+ companies running IBM z/OS Operating System.
Top industries
Information technology and services875
Financial services365
Professional and business services289
Media and telecommunications53
Industrial and manufacturing49
Education and training45
Health and wellness30
Government and public services29
No industry recorded: 70
Company size
1–10122 (7%)
11–50287 (16%)
51–250429 (23%)
251–500212 (12%)
501–1,000108 (6%)
1,001–5,000254 (14%)
5,001–10,000107 (6%)
10,001+324 (18%)
Share of companies with a recorded size, by employees.
No size recorded: 124
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Frequently asked questions
About the IBM z/OS Operating System data on this page.
How many companies use IBM z/OS Operating System?
Firmable holds confirmed IBM z/OS Operating System detections for 1,967 distinct companies, 470 of them confirmed in the last 90 days. A company is counted once however many of its properties run it.
Which companies use IBM z/OS Operating System?
THL Partners, Veritas Capital and Diné Development Corporation are among the most prominent in the current set.
What industries use IBM z/OS Operating System?
Information technology and services, financial services and professional and business services lead the set, across 19 industries in total.
What size companies use IBM z/OS Operating System?
Adoption concentrates in the 51-250 employee band, across the companies whose size is recorded.
Where are IBM z/OS Operating System users based?
The United States, Canada, Australia and Indonesia account for most detections, across 13 countries.
How current is this data?
470 companies were confirmed in the last 90 days. Last detection 7 September 2026.
