Indra Nooyi's exit: When a female CEO leaves, the glass ceiling is restored

Even at companies run by prominent women, why is their replacement hardly ever another woman?

And then there were 24.

With the announcement of Indra Nooyi’s departure on Monday as chief executive of PepsiCo, only 24 women will remain as chief executives of the top publicly traded companies that make up the Standard & Poor’s 500-stock index, accounting for just 4.8 percent of its leaders.

And the number is going down, not up. Two other female chief executives recently stepped down — Denise M. Morrison of Campbell Soup and Irene Rosenfeld of the snack food maker Mondelez International — with only one new female executive being appointed, Kathy Warden of Northrop Grumman. That should raise all sorts