Shares of UnitedHealth Group are surging before the market open Friday as Warren Buffett’s Berkshire Hathaway disclosed that it recently purchased shares of the beleaguered insurer.

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

The advance came after Buffett's conglomerate Berkshire Hathaway revealed a stake of 5 million shares, worth about $1.6 billion.

UnitedHealth shares clocked the largest one-day percent increase since March 2020, as tracked by Dow Jones Market Data Group. It was on pace for the best day in 17 years before giving back some of those gains. For the week, shares rose over 21%, the best week since May 2009. Still, the stock is down more than 50% over the past 12 months.

The Oracle of Omaha just took a $1.6 billion stake in the battered healthcare giant, sending shares soaring 9% after hours.

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.