5. Allstate (Industry: Property & Casualty Insurance)
Situated in Northfield Township, Illinois, this company is a major player in the insurance industry. Since 1931, it has evolved into the largest publicly-traded property-casualty insurance company in the nation.
It provides individual auto and property insurance, as well as business and commercial insurance, along with a diverse range of associated products. With 19 subsidiaries spanning the US, UK, Canada, and India, it maintains a significant global presence.