Wall Street has enjoyed a banner week, with broad gains for equities on the heels of the U.S.-China tariff truce. It would have looked even better if you could remove one stock. Health insurance giant UnitedHealth Group dropped more than 23% this week following a string of bad headlines. On Tuesday, the company pulled its 2025 guidance and announced that CEO Andrew Witty was stepping down . On Wednesday, The Wall Street Journal reported that the company is facing a Department of Justice investigation over possible Medicare fraud . UnitedHealth said it has not been notified of any investigation. UNH 5D mountain UnitedHealth Group had the biggest negative impact on the Dow this week. The slumping stock hurt the Dow Jones Industrial Average in particular. The 30-stock average is weighted by share price, not by the market value of a company, and even after this week’s drop, UnitedHealth still has the ninth-highest-priced stock in the Dow. All told, this week’s decline chopped off 545 points from the Dow. In other words, if the health-care stock had not moved at all this week, the Dow would have closed above 43,000 on Friday, 1.3% higher than where it actually settled. UNH was a drag on the Dow even before its latest decline. Bespoke Investment Group said in an X post on Friday that the Dow would be 4.6% higher over the past six months if the health-care provider weren’t in the average. The stock had a smaller but still negative impact on the market cap-weighted S & P 500 . UnitedHealth was still a top 40 holding in the SPDR S & P 500 ETF Trust (SPY) on Friday, but that amounts to less than 1% of the fund. One piece of good news for UnitedHealth investors came when multiple directors stepped in and bought the company’s stock this week. The purchases were small, but could still be taken as a vote of confidence in the company’s direction under a new CEO. News of the purchases helped the stock rally more than 6% on Friday. “We are in newfound valuation territory, and we are hopeful new management can help reset the trajectory, even though it will admittedly take time,” Morgan Stanley analyst Erin Wright said in a note to clients Wednesday. — CNBC’s Michael Bloom contributed reporting.