(Reuters) -Warren Buffett’s Berkshire Hathaway disclosed on Thursday that it has begun investing in UnitedHealth Group after the insurer became a target for many Americans upset over the direction of the nation’s healthcare.

Berkshire said it owned 5.04 million UnitedHealth shares worth about $1.57 billion as of June 30.

Buffett’s conglomerate also said it sold 20 million shares of Apple, its largest stock holding, in the second quarter, reducing its stake to 280 million shares.

Berkshire also revealed it has bought the common stocks of security products provider Allegion, home builder DR Horton, outdoor advertiser Lamar Advertising and steel maker Nucor, and significantly increased its stake in homebuilder Lennar.

(Reporting by Jonathan Stempel in New York; Editing by Richard Chang)