The update in the probe comes after a tumultuous last year for UnitedHealthcare, the nation's largest and most powerful private health insurer. Shares of UnitedHealthcare's parent company, UnitedHealth Group, are down more than 42% for the year after it suspended its 2025 forecast amid skyrocketing medical costs, announced the surprise exit of former CEO Andrew Witty and grappled with the reported probe into its Medicare Advantage business.