UnitedHealth (UNH) stock climbed 6.7% in Thursday afternoon trading after Warren Buffett's Berkshire Hathaway (BRK.B) (BRK.A) disclosed that it acquired a new stake in the health insurer during Q2 2025.

Warren Buffett's Berkshire Hathaway built a $1.6 billion stake in UnitedHealth last quarter, marking one of its last wagers with the investor as CEO.

Berkshire Hathaway revealed four new investments Thursday in steelmaker Nucor, insurer UnitedHealth and two of the nation’s biggest homebuilders — Lennar and DR Horton — but only one of the investments was big enough to ensure that legendary investor Warren Buffett may have handled them.

Warren Buffett's Berkshire Hathaway increased its holdings in UnitedHealth Group stock, and also added positions in D.R. Horton, Lamar Advertising, and Nucor.

Warren Buffett has added new positions in Nucor NUE, UnitedHealth Group UNH, while shedding more shares of Apple AAPL and Bank of America BAC, the quarterly Form 13-F filed with the Securities and Exchange Commission revealed on Thursday afternoon.

UnitedHealth has been the Dow’s worst performer of 2025, but jumped 13% Friday. Here’s why Buffett and other leading hedge funds suddenly love the stock.

Berkshire purchases often boost stocks. Shares of the steel maker traded as high as $151.32 on Friday, but closed at $145.48, up 0.8%. The S&P 500 fell 0.3%. The Dow Jones Industrial Average rose 0.1%.