Common stock (Tables)

3 Months Ended

Mar. 31, 2012

Changes in issued and outstanding Berkshire common stock

Changes in Berkshire’s issued and outstanding common stock during the first quarter of 2012 are shown in the table below.

	Class A, $5 Par Value (1,650,000 shares authorized)									Class B, $0.0033 Par Value (3,225,000,000 shares authorized)
	Issued			Treasury			Outstanding			Issued		Treasury			Outstanding
Balance at December 31, 2011		938,342			(98	)		938,244			1,069,645,361		(801,985	)		1,068,843,376
Conversions of Class A common stock to Class B common stock and exercises of replacement stock options issued in a business acquisition		(5,630	)		—			(5,630	)		9,029,871		—			9,029,871
Balance at March 31, 2012		932,712			(98	)		932,614			1,078,675,232		(801,985	)		1,077,873,247