The company may be under criminal investigation for alleged irregularities in its Medicare business—but it's been touched by the Warren Buffett effect.

Shares of health insurance company UnitedHealth (NYSE:UNH) jumped 3.3% in the afternoon session after its board of directors authorized the payment of a quarterly cash dividend, signaling a commitment to shareholder returns.

UnitedHealth Group (UNH) stock is still down 40% YTD but has surged more than +20% this month following reports that Warren Buffett, and other billionaire hedge fund managers have taken a stake in the company.