Arthur J. Gallagher & Co. on Tuesday announced the acquisition of San Diego-based Atlas General Holdings LLC, which operates as Atlas General Insurance Services.

Atlas, founded in 2009 by Bill Trzos, is a full-service, multiline program manager and managing general agency offering workers' compensation, commercial lines and specialty property programs nationwide, with expertise in the California workers' compensation market.

Mike Mathews, Charles Lasher and their associates will remain in their current location under the direction of Joel Cavaness, president of Risk Placement Services Inc., Gallagher's U.S.-based wholesale brokerage division.

Arthur J. Gallagher & Co., a global insurance brokerage, risk management and consulting services firm headquartered in Rolling Meadows, Illinois, did not disclose the terms of the transaction.