Walgreens Boots Alliance is to become the only company in the S&P 500 to be run by a black woman after the drugstore group appointed Starbucks chief operating officer Roz Brewer as chief executive.

Ms Brewer, 58, is to replace the Italian-born billionaire Stefano Pessina, 79, who will become executive chairman of the company he built into a global pharmacy and healthcare powerhouse.

She is due to take the helm in March of WBA, which employs more than 450,000 people and has more than 21,000 stores, with a brief to revive the fortunes of the US-based company, whose shares have lost 38 per cent in the past five years.

The New York-listed group’s bricks-and-mortar stores, which include the Walgreens and Duane Reade chains in the US and the UK’s Boots, have come under additional pressure during the coronavirus crisis. Shoppers have made fewer visits to stores in the pandemic and health services have postponed routine treatments, reducing demand for prescriptions.

This month WBA struck a deal to sell its distribution business, Alliance Healthcare, for about $6.5bn to AmerisourceBergen, the US drug wholesaler.

Wall Street welcomed Ms Brewer’s appointment, sending WBA’s shares up 8.4 per cent in after-hours trading.

WBA issued a statement announcing the move after Starbucks said earlier on Tuesday that Ms Brewer was leaving the coffee chain to join an unnamed listed company. Starbucks said the identity of the company would be disclosed in coming days, and The Wall Street Journal subsequently identified WBA.

Ms Brewer, who is a board member of Amazon, is expected to stand aside from her role at the tech group upon taking the position at WBA.

Her departure from Starbucks is the latest change in the leadership ranks at the world’s biggest coffee chain, which said this month that Patrick Grismer would stand aside as chief financial officer.

Starbucks said her responsibilities would be “distributed to other members of the existing leadership team”.

Ms Brewer’s appointment to one of the highest-profile jobs in US business comes as corporate America is under pressure to promote more women and minorities into senior management and boardroom positions. Starbucks has chosen as its next chair Mellody Hobson, who in March will become only the second black woman to lead the board of an S&P500 company.

Ms Brewer, who is ranked 27 on Fortune’s 50 Most Powerful Women in Business, has been Starbucks’ chief operating officer for more than three years, where WBA said she had been “instrumental in helping the company accelerate its growth strategy, expand its global reach and drive value”.

She previously spent more than a decade at Walmart, culminating in a five-year spell at the helm of Sam’s Club, the retailer’s warehouse club division. Before that, the chemistry graduate worked for the consumer products group Kimberly-Clark for 22 years, starting as a scientist.

Ms Brewer said in a statement that WBA was a “world-class and trusted organisation whose purpose I deeply admire”. “The healthcare industry is constantly evolving, and I am excited to work alongside the entire WBA team,” she said.

Mr Pessina will take a less hands-on role at WBA following a lengthy career in the industry, in which he led a series of increasingly large takeover and merger deals. He took charge of the group in 2015, shortly after the combination of Alliance Boots and Walgreens.

He said in a statement: “The board conducted an extensive search to identify an exceptional leader who will build on WBA’s track-record of success and take advantage of the many growth opportunities in many markets across the company. We are excited to have found that person in Roz.”

Ursula Burns became the first black woman to run an S&P500 company in 2009 when she was named chief executive of Xerox, a position she held until 2017. Mary Winston was the second in 2019 when she became interim chief of retailer Bed Bath & Beyond.

The pressure on boards to diversify has intensified since Nasdaq announced in December that companies listed on its exchange should have at least one female director and one director from an under-represented minority.

Institutional Shareholder Services, an influential investor advisory group, said it will recommend shareholders vote against the re-election of certain directors on boards lacking diversity from next year.

Additional reporting by Andrew Edgecliffe-Johnson in New York