Breaking The ‘Concrete’ Ceiling: Roz Brewer To Become The S&P 500’s Only Black Female CEO Rosalind “Roz” Brewer is the 48th most powerful woman in the world and poised to become even more powerful: On Tuesday night, news broke that Brewer will become CEO of Walgreens Boots Alliance in March. Brewer will be the only Black woman chief executive of an S&P 500 company.