DalsnaFinance › Headquarters › Illinois
118 public companies are headquartered in Illinois, including 27 in the S&P 500 or Nasdaq-100. The biggest concentrations are in Chicago, Northbrook and Downers Grove.
118 companies · 42 cities · 27 ★ index members
Headquarters are each company's principal executive office as filed with the SEC (EDGAR business address), as of October 3, 2026. ★ marks S&P 500 and Nasdaq-100 members. All locations.