A Class B tem proporcionalmente menos direito a voto:
http://www.berkshirehathaway.com/compab.pdfComparison of Berkshire Hathaway Inc. Class A and Class B Common Stock
Berkshire Hathaway Inc. has two classes of common stock designated Class A and Class B. A share of Class B common stock has the rights of 1/1,500th of a share of Class A common stock except that a Class B share has 1/10,000th of the voting rights of a Class A share (rather than 1/1,500th of the vote).