Even in an age of consolidation, last week’s announced merger between West L.A.’s RBZ, the fifth-largest accounting firm headquartered in Los Angeles, and San Ramon’s Armanino was a surprise to some.

The merger between HDFC, a major housing finance company, and HDFC Bank, the country’s largest private lender, will take effect on July 1. Speaking to the Times of India, HDFC Chairman Deepak Parekh ...