Key Points UnitedHealth Group delivered the S&P 500's strongest performance in August 2025 with a 24.2% gain. The health insurer rebounded from a brutal 20% July decline caused by disappointing earnings results. Last month's big jump came from a Berkshire Hathaway investment in the stock and a long-suffering deal finally closing. 10 stocks we like better than UnitedHealth Group › The S&P 500 (SNPINDEX: ^GSPC) market index gained 1.9% in August 2025. That may not sound like much, but it's actually ...