UnitedHealth shares fell more than 4% on Wednesday before finishing down 1%, a day after hedge-fund manager Bill Ackman wrote a post on social media that said the insurer could be overstating its profits because it denies patients medically necessary care.

UnitedHealth Group has raised concerns with the top US securities regulator over a social media post by activist investor Bill Ackman, who claimed that the healthcare group could be inflating its profits.

UnitedHealth (NYSE:UNH) has contacted the US Securities and Exchange Commission about its issues with hedge fund investor Bill Ackman's since-deleted post on X. Shares of UnitedHealth fell 2.3% in the wake of the Ackman posting.