Class A shares of Warren Buffett's Berkshire Hathaway fell more than 3% in afternoon trading on Monday, as investors fretted over a $3.8 billion write-down and a dip in quarterly operating profit that the firm disclosed on Saturday.

According to a regulatory filing late Monday, Berkshire Hathaway sold approximately 1.64 million shares of DaVita Inc. on July 31, at an average price of $140.61 per share, totaling around $230 million,