Apparently sexism in the workplace doesn't only hurt careers. It also hurts bottom lines.

That's because public companies with female board members perform significantly better than those without them, according to a new study by the Credit Suisse Research Institute (h/t ThinkProgress and Bloomberg).

The stock prices of small and mid-size companies with at least one female board member have performed 17 percent better over the past six years than those without one, the survey found. The difference is even wider at large companies, where female-friendly boards perform 26 percent better.

"Stocks of companies with women on boards tend to be a little more risk averse and have on average a little less debt, which seems to be one of the key reasons why they've outperformed so strongly in this particular period," Mary Curtis, a research director at Credit Suisse and co-author of the report, told Bloomberg.

Eighty-six percent of U.S. companies had at least one woman on their board of directors last year, compared to 59 percent globally, according to the study. In 2005, only 73 percent of U.S. companies and 41 percent of global companies had women on their boards.

Some companies may be starting to see the value of bringing women on board. In June, Facebook named Sheryl Sandberg, its chief operating officer since 2008, the company's first female board member. So far, that's done little to help the company's plunging stock price.

There is still a long way to go before breaking that corporate glass ceiling. Only about 19 of the Fortune 500 CEOs, or 8 percent of them, are women.