Walgreens' Stefano Pessina will step down as CEO and become executive chairman once the drugstore chain finds a replacement for him.
The current executive chairman, former McDonald's CEO Jim Skinner, will remain on the board after Pessina takes over.
The company announced no time frame Monday in finding a successor to the 79-year-old Pessina.
Pessina told Walgreens Boots Alliance Inc. board members in a letter dated July 23 that he has thought about stepping down "for some time, but for the reasons the Board knows, the time was not right to do so."
In the letter, he said he thought now was the right time to find a successor.
The leadership changes didn't surprise Edward Jones analyst John Boylan, who noted Pessina's age. But the analyst said the fact that no new CEO was immediately named came as a "modest surprise."
Boylan said he thinks there's an opportunity for Walgreens to hire someone from outside the company to bring in fresh ideas. But he also noted that Pessina will still hold considerable sway as one of the company's largest shareholders.
Pessina has a stake of more than 16%, according to FactSet.
The change in leadership comes a couple weeks after Walgreens announced a huge quarterly loss and a major business pivot.
Walgreens posted a $1.7 billion loss in the quarter that ended May 31 with millions of people sheltering at home due to the rapidly spreading COVID-19 pandemic.
Walgreens was particularly hurt in the quarter by plunging sales from its Boots stores in the United Kingdom. But even before the pandemic set in, the drugstore chain had embarked on major cost-cutting plan to improve its performance.
The chain also announced earlier this month that it will squeeze primary care clinics into as many as 700 of its U.S. stores over the next few years in a bid to play a greater role in managing customer health.
Drugstores like Walgreens and rival CVS Health Corp. typically tuck small clinics in the back of their stores to dole out flu shots or treat minor ailments like sinus infections or poison ivy. But Walgreens is closing many of those clinics and redesigning some stores to fit larger primary care offices to offer more comprehensive care.
Walgreens, based in Deerfield, Illinois, runs more than 9,200 stores in the United States and has more than 18,750 locations internationally.
Pessina has been CEO since 2015, after Walgreens combined with European health and beauty retailer Alliance Boots to create the current company.
Skinner, 75, has served as executive chairman since January 2015.
Company shares slid around 2% to $39.96 Monday in a largely positive day for U.S. markets.
The stock has already shed more than 30% of its value so far this year. That's more than three times as big as the 7% decline registered by the Dow Jones industrial average, of which Walgreens is a component.