Studies have shown that the presence of women on boards and in executive offices can lead to better financial performance. But some companies haven't gotten the message and are sticking with practices that should have gone out with the Eisenhower era. In fact, seven S&P 500 companies have no women directors, according to data from BoardEx, a relationship capital services provider owned by TheStreet. Here are three of the worst offenders, with share prices that are down at least 15% over the past 12 months:

Discovery Communications
Consumer Goods & Services/Broadcasting

It seems counterintuitive that a media entertainment company that is looking to attract female viewership and is the co-producer of a network owned by one of the most successful female executives of our time, Oprah Winfrey, does not have a single female board member. But, indeed, Discovery Communications (DISCA - Get Report) boasts zero female directors -- nor has it had any since it went public in 2008, according to BoardEx.

Discovery's 10-person board of directors is headed by non-executive chairman Robert Miron.

The $10.7-billion market cap chief executive, David Zaslav, has also been named this year's most overpaid CEO, according to corporate governance and social responsibility non-profit organization As You Sow.

Discovery shares are down 15.3% over a 12-month period.

Discovery has only two female members of its executive management team: Adria Alpert Romm, its head of human resources and global diversity, and Majorie Kaplan, the president of content for Discovery Networks International, according to the company's Web site.

Discovery shares are down 15.3% over a 12-month period.

A Discovery spokeswoman did not immediately return a request for comment.


Garmin

Consumer Goods & Services/Consumer Electronics

Garmin (GRMN - Get Report) creates and manufactures consumer electronic products. The $7.4-billion market cap company manufactures a wide range of navigation and information devices across industries, from smartwatches to marine electronics systems.

Garmin's seven-person board is headed by Min Kao, its executive chairman. CEO and President Clifton Pemble is also on the board of directors. The company has not had female representation on its board in at least the last 10 years, according to BoardEx. The lack of gender diversity on its board is curious, given that the company manufactures wearable technology products, such as its vivofit activity tracker, that are marketed to both men and women.

Only two of Garmin's 10-person management team are women. The first is Dawn Iddings, its vice president of business development and customer care. The second is Laurie Minard, its vice president of human resources.

Garmin shares are down 19.84% over the last 12 months.

Garmin has been actively "seeking to nominate a suitable female candidate" for some time, according to spokesman Ted Gartner in an emailed statement. "The board expects to nominate a female director candidate at our annual meeting in 2016," which usually takes place in June.

Diamond Offshore Drilling
Energy/Oil & Gas Drilling

Diamond Offshore Drilling (DO - Get Report) is an offshore drilling company that provides contract drilling services to the energy industry. The $3 billion market cap company's CEO is Marc Edwards.

Diamond Offshore Drillings' 11-person board of directors is headed by James Tisch, the president and CEO of hotel chain Loews. (His brother, Andrew, is also on the board of directors.) There have been no women on Diamond Offshore Drillings' board in the last 10 years, BoardEx found.

In an industry in which the majority players are men, the Houston-based company has just one member of management that is a woman: Beth Gordon, its controller, according to its Web site.

Diamond Offshore Drilling shares are down 21.8% over the past 12 months.

"Our board recognizes the benefits of broad diversity throughout the company and agrees with the merits of achieving diversity," Diamond Offshore Drilling responded in an emailed statement. "The board considers diversity broadly to include diversity of race, ethnicity and gender, but also diversity of viewpoint, professional experience, and individual characteristics, qualities and skills, resulting in the inclusion of naturally varying perspectives among the directors.

"For example, our board currently includes individuals with broad experience in the energy industry, business, finance, academia, international relations and public affairs. When assessing individual nominees to fill a board vacancy in the future, the board will consider all relevant factors, including, among others, diversity, career achievements, breadth of experience, soundness of judgment, ability to make independent analytical inquiries and ability to represent the total corporate interests of our company and our stockholders."Discovery has only two female members of its executive management team: Adria Alpert Romm, its head of human resources and global diversity, and Majorie Kaplan, the president of content for Discovery Networks International, according to the company's Web site. 

 
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