The chief executive officer of a company runs the operations and sales and marketing and everything that the company needs. The chairman of the board runs the company’s management, making sure they’re working hard for the company.

Historically, one person has had both jobs. But that’s changed — especially for companies in crisis. Today, more than 50% of S&P 500 companies have split the roles. Companies facing crises (take, recently, Boeing and WeWork) will hire a separate chairman in a bid to let the CEO focus on recovery.

Wall Street Journal reporter Thomas Gryta spoke with “Marketplace” host Kai Ryssdal about his article on the trend and why it matters.