Common stock (Tables)

6 Months Ended

Jun. 30, 2011

Changes in issued and outstanding Berkshire common stock

Changes in issued and outstanding Berkshire common stock during the first six months of 2011 are shown in the table below.

	Class A, $5 Par Value		Class B, $0.0033 Par Value
	(1,650,000 shares authorized) Shares Issued and Outstanding		(3,225,000,000 shares authorized) Shares Issued and Outstanding
Balance at December 31, 2010	947,460		1,050,990,468
Shares issued to acquire noncontrolling interests of Wesco Financial Corporation	—		3,253,472
Conversions of Class A common stock to Class B common stock and exercises of replacement stock options issued in the BNSF acquisition	(6,698	)	11,522,505
Balance at June 30, 2011	940,762		1,065,766,445