In his latest letter to shareholders, Buffett said that property and casualty (P&C) "continues to be Berkshire's core business." More than 10% of the conglomerate's total earnings last year stemmed from insurance premiums. Investment income from Berkshire's insurance business generated another 15% of total earnings. Buffett said at the recent annual shareholder meeting that GEICO's auto insurance "is by far the largest item in the property & casualty insurance business. It's huge." Ajit Jain, who heads Berk ...