317-622-8970Search all companies →Largest IT Companies in Illinois (2026)
Factur's directory lists 5,647 IT companies in Illinois. These are the 10 largest of them by annual revenue, led by Morningstar Inc ($2.4B), Alight ($2.3B) and Paylocity ($1.7B).
Size mix: of the 5,647 with a known headcount, 90.9% have 1-50 employees, 6.7% 51-200, 1.9% 201-1000, 26 companies 1001-5000 and 5 companies 5001+. 68 employ more than 500 people.
The 10 largest IT companies in Illinois by annual revenue
| # | Company | City | Employees | Annual revenue |
|---|---|---|---|---|
| 1 | Morningstar Inc | Chicago | 10,973 | $2.4B |
| 2 | Alight | Lincolnshire | 9,500 | $2.3B |
| 3 | Paylocity | Schaumburg | 6,700 | $1.7B |
| 4 | IFS | Linkoping | 6,000 | $1.7B |
| 5 | Paylocity | Schaumburg | 6,400 | $1.4B |
| 6 | Tempus AI Inc | Chicago | 2,400 | $952M |
| 7 | CCC Intelligent Solutions Holdings Inc | Chicago | 2,491 | $945M |
| 8 | Cision US Inc | Chicago | 4,000 | $826M |
| 9 | Donnelley Financial Solutions Inc | Chicago | 1,750 | $767M |
| 10 | Denkei Corporation Americas | Schaumburg | 3,836 | $753M |
How this list is ranked
Companies are ranked by annual revenue (USD) as recorded on each company's profile in the Factur directory, highest first; companies with the same revenue are ordered by employee count. Only companies with a positive revenue figure on file are ranked, so a large private company with no reported revenue can be missing. The list covers companies whose record places them in Illinois and whose Factur industry is IT. Figures are a snapshot of the directory, refreshed when the rankings are regenerated; open a profile for its current data.