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5,647 companies in IT in Illinois.
Explore 5,647 IT in Illinois listed with contact details, employee size, revenue, and NAICS/SIC codes. Compare suppliers and service providers side by side and reach the right companies directly, or view the same industry in IT in California, IT in New York, IT in Texas.
Largest IT in Illinois companies by revenue
The highest-revenue companies in this directory. Open any profile for its full firmographics.
| # | Company | Location | Employees | 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 |
IT in Illinois companies by size and revenue
| Employees | Companies | Share |
|---|---|---|
| 1-50 | 5,131 | 90.9% |
| 51-200 | 379 | 6.7% |
| 201-1000 | 106 | 1.9% |
| 1001-5000 | 26 | 0.5% |
| 5001+ | 5 | 0.1% |
| Revenue | Companies | Share |
|---|---|---|
| Under $10M | 5,174 | 91.8% |
| $10M-$50M | 360 | 6.4% |
| $50M-$250M | 68 | 1.2% |
| $250M-$1B | 28 | 0.5% |
| $1B+ | 5 | 0.1% |
Share is of companies with a known value — 5,647 with headcount and 5,635 with revenue on file, as of Jul 17, 2026.
Frequently asked questions
How many IT in Illinois are there?
There are 5,647 IT in Illinois in the directory. Use the filters to narrow by employee count, revenue, or NAICS/SIC code.
How many large companies are in IT in Illinois?
68 of the 5,647 companies in IT in Illinois employ more than 500 people, and 5 report over $1 billion in annual revenue. See the size and revenue breakdown above for the full distribution.
What size are most IT in Illinois companies?
Most are small and mid-sized businesses: the size and revenue tables above show the full spread, from under $10M up to $1B+, across the 5,635 companies with revenue on file.
What information is included for each company?
Every listing includes the company name, location, website, employee size, revenue range where available, and NAICS/SIC classification, with a link to the full profile.
Where does this directory come from?
Listings are compiled and maintained by Factur, a sales and marketing firm for B2B manufacturers. Any company can request an update or removal from its profile page.