In 2011, Susan Wolford, a Los Angeles-based wealth advisor for Morgan Stanley, got an extraordinary referral. The beneficiary of a large estate wanted to meet with her to discuss managing her investments specifically because Wolford was accredited in domestic-partner tax and estate planning — and openly gay. The potential client made it very clear that “she wants someone who might deal with her and her partner in an all-encompassing way,” the referring attorney told Wolford. Wolford’s consultancy earns one percent on assets it manages, so the client’s decision to go with her group amounted to a substantial sum — quite a testament to the power of being out in the workplace.

Corporations and individuals are increasingly embracing lesbian, gay, bisexual and transgender (LGBT) status as an emerging career asset. The United States Congress is also moving to endorse the value of “out.” This past April, bipartisan coalitions in the House and Senate introduced a new version of the Employment Non-Discrimination Act (ENDA) that would prohibit job discrimination based on sexual orientation and gender identity. The Senate is scheduled to begin discussions on the bill in early July.

Recent research from the Center for Talent Innovation, a New York-based think tank where I serve as president, details the benefits of an inclusive work environment. For lesbian, gay, bisexual and transgender (LGBT) employees, feeling comfortable about being out at work opens up access to business opportunities like Wolford’s as well as platforms on which to exercise leadership. In addition, CTI survey results found that 15% of men and 10% of women believe they’ve expanded their networks thanks to their LGBT status. By joining internal employee resource groups or participating in LGBT fundraisers or philanthropic endeavors, they were able to mingle with senior leaders they might otherwise never have met and leverage those relationships.

Most important, out employees are better able to gain the attention and advocacy of their superiors. Sponsorship, as we’ve explained in HBR articles and blogs, lends enormous traction to any ambitious person’s career. Among LGBT individuals, those without powerful backers, whether heterosexual or gay themselves, are far more likely to feel stalled in their careers, unrecognized for their talents, and lacking in career development opportunities. By contrast, those with sponsors are much more likely to report that they are being promoted quickly, are satisfied with their rate of promotion, and are moving up through the hierarchy of their industries.

LGBT employees aren’t the only beneficiaries of an inclusive workplace; employers benefit, too. In 2012, LGBT adults in the U.S. represented $790 billion in total buying power, making them a market force companies can’t afford to overlook. Inclusive companies find that publicizing their support of LGBT equality boosts their standing among consumers across the board: 71% of LGBT adults said they are likely to remain loyal to a brand they believe to be very friendly to the LGBT community even when less friendly companies may offer lower prices or be more convenient. Further, three-quarters of heterosexuals and 87% of LGBTs said they would consider choosing a brand known to provide equal workplace benefits.

Yet despite advances in workplace acceptance, over 40% of LGBT workers remain closeted at the office.

And even though LGBT employees, both in and out of the closet, are every bit as ambitious and motivated to succeed as their heterosexual peers, because closeted LBGT employees feel so much more dissatisfied with their career paths, they are much more likely to have one foot out the door. CTI research found that those who are unhappy with their rate of promotion or advancement are at least three times more likely than those who are satisfied to plan to leave their company within the next year. LGBTs who feel isolated at work — in other words, closeted LGBT employees burdened with the daily stress of keeping their private life secret from their colleagues — are 73% more likely than their out peers to say they intend to jump ship within the next three years.

What makes work a place where LGBT talent can thrive? Allies — people who support or work as LGBT advocates — play a decisive role in creating an open community where individuals are comfortable being themselves. In fact, 24% of LGBT workers surveyed attribute their decision to come out professionally to a strong network of allies. However, although the ally phenomenon is widespread and growing, few men and women qualify as “active allies,” that is, those who openly support LGBT colleagues at work.

Increasing those percentages is directly tied to the growth of the out LGBT population and the war for talent. As more people come out, more of the heterosexuals who know them wish to lend their support. One of the driving forces for allies voicing their support is the realization that LGBT high-performers simply won’t stay with a company that doesn’t make them feel welcome.

“If we want to recruit and retain the best talent out there, we have a responsibility to make this a place where everyone feels comfortable,” says Eric Jordan, an active ally at Goldman Sachs, whose CEO, Lloyd Blankfein, became Wall Street’s highest-ranking ally when he created a video in support of same-sex marriage in early 2012. “Along with being the right thing to do, the business case for diversity is real and we want to be able to attract and keep the best people.”