Book value, a measure of assets minus liabilities, rose to $59.94 a share at the main business, from $54.63 on March 31.

While his early handling of the crisis was good, he has balked at selling assets for less than book value, even though the bank’s shares have for some time traded at a steep discount to that measure.

Buffett's preferred measure of Berkshire's performance is the growth in its book value, which is a calculation of the company's assets minus its liabilities.