Decades after the civil-rights movement led to laws banning workplace discrimination, progress for Black executives has hit a ceiling.

“Opportunity is not equally distributed,” says Ron Williams, the Black former CEO of Aetna who has served on 14 boards over his career and currently sits on the boards of Boeing Co. and American Express Co. Too many promotions in companies are informally decided before jobs are ever posted, leaving Black people and more marginalized talent without the chance to compete, he says. “People don’t get the chance to work their way into a position where they are a reasonable candidate for a role,” he says.

…The ranks of Black chief executives have stayed low even as other ethnic minorities have seen greater, albeit still limited, advancement. Among CEOs of S&P 500 companies, 11% are ethnic minorities. Of the total, 3% are Latino, 3% are Indian, 2% are Asian, 1% are Middle Eastern and 1% are multiracial. Just 1% are Black, according to an analysis by MyLogIQ, a data tracker. Black people make up about 13% of the U.S. population.