Billionaire Family Offices Join Berkshire’s UnitedHealth Bet (1)

Some of the world’s wealthiest people joined Warren Buffett’s Berkshire Hathaway Inc. in buying shares of embattled insurer UnitedHealth Group Inc. in the second quarter.

George Soros’ investment firm, the family office of a Swedish packaging dynasty and Michael Platt’s BlueCrest Capital Managementall increased their stakes in UnitedHealth last quarter, according to 13F filings published Thursday.

The disclosed investments sent shares soaring and are a rare bright spot of late for UnitedHealth, which has largely struggled since one of its top executives was fatally shot in New York City in December. The health-care company, which is under ...