Arthur J. Gallagher & Co. (NYSE:AJG), a global insurance brokerage, risk management and consulting services firm, is headquartered in Rolling Meadows, Illinois. Gallagher provides these services in approximately 130 countries around the world through its owned operations and a network of correspondent brokers and consultants. ROLLING MEADOWS, Ill., Aug. 4, 2025 /PRNewswire/ -- Arthur J. Gallagher & Co. today announced the acquisition of Novi, Michigan-based Dion Leadership, Inc. Terms of the transaction wer ...