Warren Buffett's Berkshire Hathaway Inc. late Friday said its third-quarter operating earnings fell to $4.55 billion from $4.72 billion a year earlier. On a per share basis, Berkshire Hathaway earned $2,769 versus $2,876. Investment and derivative gains during the quarter totaled $4.88 billion, compared with a loss of $107 million in the same period last year. However, its net income surged to $9.43 billion, or $5,737 a class A share, from $4.62 billion, or $2,811 a share, a year ago. Berkshire's book value, a measure of net worth, rose 3.