Berkshire Hathaway, led by Warren Buffett, disclosed a new $1.57 billion stake in UnitedHealth Group (UNH) during the second quarter of 2025, acquiring 5 million shares. This investment caused UnitedHealth's stock to surge over 13% in after-hours trading and extend gains to more than 20% in subsequent sessions, marking one of the largest intraday rallies since 2008. The move by Buffett follows a period in which UnitedHealth shares had lost nearly half their value due to challenges adapting to rising healthcare costs and changes in government reimbursement plans. Alongside Buffett, investor Michael Burry also increased his position in UnitedHealth, with shares and call options valued at approximately $115 million. Berkshire Hathaway's stake has contributed to renewed market confidence in UnitedHealth's growth prospects, despite recent earnings estimates declines. The stock reclaimed key technical levels, including closing above its 50-day moving average for the first time since April 2025, with analysts identifying resistance points around $310 and potential targets near $326 and $340. Additionally, Berkshire Hathaway has been increasing holdings in homebuilders and building supply firms while trimming stakes in Apple and Bank of America. The company's cash reserves reached a record $347.7 billion, representing 29.9% of total assets, the highest since 2005. UnitedHealth remains a major component of the Dow Jones Industrial Average, having been its largest holding four months prior.