In January 2021, blum shapiro merged with CLA, the eighth largest accounting firm in the U.S. as measured by annual revenues. As a result of the combination, team members of blum shapiro joined CLA.

Prior to the merger, blum shapiro was the largest regional accounting firm based in New England. It had offices in Connecticut, Massachusetts, and Rhode Island. The firm was formed in 1980 when Blum, Gavens & Kaplan merged with Shapiro, Rosenthal & Company, P.C. The firm had more than 500 employees and was led by Joseph Kask, its CEO.