Feb 13 (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%.