(Reuters) - Warren Buffett's Berkshire Hathaway disclosed on Thursday a new investment 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.

The disclosure came in a U.S. Securities and Exchange Commission filing detailing Berkshire's U.S.-listed common stock holdings as of June 30.

UnitedHealth shares soared over 10% in after-hours trading.

Buffett's conglomerate also said it sold 20 million shares of iPhone maker Apple in the second quarter, reducing its largest stock holding to 280 million shares, and cut back another major holding, Bank of America.

Berkshire also boosted its bet on home builders, revealing a new stake in DR Horton and significantly larger stake in Lennar.

The filing also disclosed new Berkshire investments in security products provider Allegion, outdoor advertiser Lamar Advertising and steel maker Nucor

It is not clear whether Buffett, his portfolio managers Todd Combs and Ted Weschler, or future Chief Executive Greg Abel are behind individual purchases and sales.

But stock prices often rise when Berkshire makes purchases because investors view them as a seal of approval from Buffett.

DR Horton, Lennar, Allegion, Lamar and Nucor also rose in after-hours trading.

TAPEWORM

Shares of UnitedHealth, part of the Dow Jones industrial average, had through Thursday fallen 46% this year amid rising costs, a U.S. Department of Justice probe related to its billing practices, a cyberattack, and the shooting death of former top executive Brian Thompson last December.

Buffett has called high health care costs a "tapeworm" that limits economic growth, and with JPMorgan Chase's Jamie Dimon and Amazon.com's Jeff Bezos tried unsuccessfully to improve healthcare for their companies' employees.

Their joint venture, Haven, shut down after three years in 2021.

UnitedHealth did not immediately respond to requests for comment on Berkshire's investment.

The Apple sales, Berkshire's first since the third quarter of 2024, further reduced what was once a 905 million share stake, but do not signal a full-blown retreat from the stock.

Apple shares were little changed after hours.

Despite the new purchases, Berkshire sold $3 billion more stocks than it bought between April and June, the 11th straight quarter it was a net seller of stocks. It ended June with $344.1 billion of cash and equivalents.

Other changes in Thursday's filing included larger stakes in oil company Chevron, alcoholic beverages maker Constellation Brands and Domino's Pizza, and exiting a stake in wireless network operator T-Mobile.

Berkshire also revealed it had been buying DR Horton, Lennar and Nucor stock before April, but the SEC let it keep the purchases confidential so investors would not try to piggyback.

Based in Omaha, Nebraska, Berkshire also owns close to 200 businesses including Geico car insurance, the BNSF railroad, and many energy, industrial, retail and service companies.

Buffett turns 95 on August 30. He is expected to remain Berkshire's chairman after Abel, 63, becomes chief executive on January 1, 2026.