Editors' pick: Originally published March 10.

Corporate board meetings at seven companies in the S&P 500 are conducted with no female representation, according to data collected by BoardEx, a relationship capital services provider owned by TheStreet.

That number is down more than 50% from 2014, when 16 S&P 500 companies had no female board members at year's end, BoardEx noted. But the fact that any boardrooms in 2016 could be completely devoid of women is troubling from a cultural perspective and unconscionable as a financial matter. After all, research strongly suggests that companies with diverse boards are better investments. And that phenomenon is borne out by the performance of the seven laggards identified by BoardEx: The average return over the last 12 months of companies without female board members was -12.72% (excluding dividends), compared with -2.57% for the broader S&P 500.

State Street Global Advisors this week underscored this dynamic by launching its SPDR SSGA Gender Diversity Index ETF, which the firm says tracks companies "with the highest levels within their sectors of gender diversity on their boards of directors and in their senior leadership." State Street, which is marking the fund's debut by ringing the closing bell at the NYSE on March 10, cites a study showing that companies with at least three female board members "outperformed others in overall return on equity by more than 36 percent."

Too many companies, though, still haven't gotten the message. The low level of female representation on corporate boards is exacerbated by the small percentage of women who are CEOs of S&P 500 companies. Just 22, or 4%, of the index's companies currently are headed by women, BoardEx said. The lack of gender equality is worse at the seven companies without female directors. Women executives among their upper management teams are few and far between. No company had more than two female members of upper management.

So which companies haven't found their way out of the Eisenhower era?

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1. 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.

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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.

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2. 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. 

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3. 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."

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4. Linear Technology

Linear Technology (LLTC) has been designing, manufacturing and marketing a broad line of high-performance analog integrated circuits for major companies worldwide for over three decades. The $10.3-billion market cap company, founded in 1981, is headquartered in Milpitas, Calif.

Linear Technology's board of directors is small, it is made up of only seven members, including Robert Swanson Jr., its executive chairman and co-founder, and Lothar Maier, its chief executive, according to last year's proxy filing. It has not had a female board member in at least the past 10 years, according to BoardEx.

Linear Technology shares are down 8.6% over a 12-month period.

"Linear Technology has had a very stable board of directors in place for many years," the company said in an e-mailed statement to TheStreet. "Each of our five outside board directors brings something unique to the company."

"In filling a future board seat should one become vacant, the company will consider 'such factors as judgment, independence, character and integrity, area of expertise, diversity of experience (including age, gender, international background, race and professional experience), length of service and potential conflicts of interest," Linear Technology noted, referring to its nominating and corporate governance policy.

Linear also said it is "committed to diversity in hiring and management" -- though none of the company's top five executives are women.

5. Qorvo

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Qorvo(QRVO) - Get Report is a semiconductor company dually headquartered in Greensboro, N.C., and Hillsboro, Ore., thanks to its 2015 merger. The $6.4 billion market cap company is a leading provider of core technologies and RF solutions for mobile, infrastructure and aerospace/defense applications, according to its Web site.

Qorvo was created last year by the merger between TriQuint Semiconductor and RF Micro Devices.

Qorvo's 10-person board of directors is comprised entirely of men, with Robert Bruggeworth as its CEO and Ralph Quinsey as its chairman. Quinsey was previously president and CEO of TriQuint. Bruggeworth was previously RFMD's president and CEO.

Its management team is also primarily men. Brandi Frye, the company's vice president of marketing, is Qorvo's only female management executive.

Qorvo shares are down 34.4% over a 12-month period.

A Qorvo spokesman did not immediately return a request for comment.

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6. Concho Resources
Energy/Oil & Gas Exploration & Production

Concho Resources(CXO) - Get Report operates one of the largest horizontal drilling programs in the Permian basin and is headquartered in Midland, Texas, according to the company's Web site.

Concho Resources Chairman and CEO Tim Leach leads its eight-person board of directors, none of whom are women. While the company went public in 2007, it just entered the S&P 500 in February 2016. It has not had any female board members since it went public, according to BoardEx -- nor does Concho Resources have any women in its upper management team, according its Web site.

CEO Leach has been in the executive management position since the $11.7-billion market cap company's formation in 2004. Prior to that, Leach was also the chairman and CEO of Concho Resources predecessor, Concho Oil & Gas, founded in 1997.

Concho Resources is down 10.4% over the past 12 months.

A Concho Resources representative did not respond to a phone call request for comment.

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7. Dentsply Sirona 
Health Care/Health Care Supplies

Dentsply Sirona(XRAY) - Get Report is the newly formed company following the merger between Dentsply International and Sirona Dental Systems, announced in September 2015 and completed last month. The combined $8.7 billion market cap company supplies products and services to the dental industry.

The combined company has zero female directors, despite the fact that Paula H.J. Cholmondeley sat on Dentsply's board for nearly 15 years. Cholmondeley resigned as of Feb. 29, the same day as the merger's closing. The new company also has zero females in upper management.

At the time of the merger's announcement, the two companies said at merger completion, Sirona's CEO Jeffrey Slovin would serve as chief executive of the combined company and be a member of the board, while Bret Wise, Dentsply's chairman and CEO, would serve as executive chairman. The board would consist of 11 members, six of whom would be current Dentsply directors and five of whom would be from Sirona.

Dentsply Sirona said in the Feb. 29 regulatory filing that directors Paula H. Cholmondeley, William F. Hecht, John L. Miclot and John C. Miles II resigned from the board but that "no director resigned because of any disagreement with the company on any matter relating to the company's operations, policies or practices."

Cholmondeley's career has been significant. She is the founder of The Sorrel Group, a firm she started in 2004 that provides education and consulting to corporate directors.

She currently sits on the board of directors for Terex (TEX) - Get Reportand as a trustee for Nationwide Mutual Funds. Cholmondeley, 68, has also sat on the boards of Minerals Technologies(MTX) - Get Report and Ultralife (ULBI) - Get Report , as well as a number of non-profit organizations. Cholmondeley has held executive positions with Westinghouse Elevator Company and Blue Cross of Greater Philadelphia. She served as a White House Fellow and assistant to the U.S. Trade Representative during 1982 and 1983.

Dentsply shares are up 21.3% over the last 12 months.

A spokeswoman for Dentsply Sirona did not return a phone call and e-mail request for comment. Ms. Cholmondeley also did not return e-mailed requests for comment.