''WOMEN ' !CORPORATE! WORLD''

FEWER WOMEN calling the Corporate shots?

The number of women leading the largest companies has always been small. This year, it got 25 percent smaller.

The reversal is leading to a search beyond the usual explanations for why women don't become chief executives for why women don't become chief executives - things like -

Not being competitive enough - failing to chase opportunities for promotion and choosing work-life balance over high-powered jobs.

That's because evidence shows that the obstacles for female executives aren't just because of their  individual choices. There are larger forces at work, experts say, rooted in biases against women in power,  mothers who work or leaders who don't fit the mold of the people who led before them.

For many years, it seemed like the share of women at the top of corporate America would slowly increase. The number of women leading companies in the Fortune 500 had grown to 6.4 percent last year, a record, from 2.6 percent a decade earlier.

But this year, the number of female chief executives declined  25 percent, according to Fortune's 2018 list, which was just recently published.

There are now 24 women, down from 32. Twelve left their jobs - most recently Denise Morrison of Campbell Soup Company, who abruptly announced her retirement last week,  and four joined the list.

Four said they were retiring; four left after their companies were acquired; two took new jobs, and two were replaced after calls for change from investors. Among the hundreds of men on the list, just 47 left, a far smaller share.

And when women leave the top job, there are fewer women in the pipeline who might take their place. In each case in which a new or interim  chief executive  was appointed, the woman was replaced by man.

The 25 percent decline is so large in part because  women's  numbers are so small to start with. There's also a phenomenon known as the  glass cliff, in which women are more likely to be put in charge of  failing companies.

But in many ways, the reasons the number of  female chief executives  is falling are the the same reasons there aren't more of them in the first place.

The Honor and Serving of the latest Global Operational Research on Women Executives and the Corporate World, continues, to Part 2. !WOW! thanks author and researcher Claire Cain Miller.