Buffett sparks UnitedHealth's biggest weekly stock surge in 16 years

Group 1 - Warren Buffett has taken a $1.6 billion stake in UnitedHealthcare Group, which has positively impacted the company's share price [1][5] - UnitedHealth shares experienced the largest one-day percent increase since March 2020, with a weekly rise of over 21%, marking the best week since May 2009, although the stock is still down more than 50% over the past 12 months [2] - Investors have shown increased interest in healthcare-related ETFs, such as Vanguard Health Care Index Fund ETF and The Health Care Select Sector SPDR Fund, following Buffett's investment [2] Group 2 - UnitedHealthcare Group is currently under investigation by the Department of Justice, which has added pressure to the company amidst other challenges, including the fallout from the murder of executive Brian Thompson [6] - The recent developments have drawn attention to the healthcare insurance system in the U.S., highlighting potential vulnerabilities and risks within the industry [6]