(Reuters) - Berkshire Hathaway ( BRK/A ) said on Thursday night it sold 203,091 shares of DaVita ( DVA ), reducing its stake in the kidney dialysis services provider to about 35.89 million shares, a 45% stake worth nearly $6.4 billion.

In a regulatory filing, Berkshire said the February 11 sale was required pursuant to a share repurchase agreement, under which DaVita ( DVA ) agreed on a quarterly basis to buy back enough shares to reduce Berkshire's ownership stake to 45%.