Law firms are moving more quickly than any other industry to offer equitable benefits for lesbian, gay, bisexual and transgender employees and their families, according to a survey of 688 major U.S. corporations done by the District-based Human Rights Campaign Foundation.

Law firms are outpacing the banking and financial services industries — historically the sectors that offered the best benefits — on improving family leave, partner coverage, retirement options and other benefits, said Deena Fidas of the Human Rights Campaign Foundation, which consults with companies on policies and benefits for LGBT employees, including diversity managers and leadership committees at law firms.

“Historically, banking and financial services was the leading industry for LGBT workplace equality,” Fidas said. “As soon as we started surveying law firms, they quickly eclipsed that.”

More than 140 law firms, including many of the largest U.S. firms, were surveyed this year.

Seventy-one of the law firms got a perfect score on the index, which measures 40 policies and practices, including benefits, companies’ pro bono efforts on LGBT issues such as speaking up for LGBT equality, and internal training and networking opportunities for LGBT-allied employees. That percentage is a dramatic jump from five years ago, when just 30 percent of law firms received a perfect score.

In contrast, 33 percent of the banking and finance companies had a perfect score, followed by retail (19 percent) and consulting (14 percent).

Among the District-based firms with perfect scores are Akin Gump, Arnold & Porter, Covington & Burling, Crowell & Moring and WilmerHale.

“The explanation for its growth is the competitive nature for top talent across the business community,” Fidas said. “Whether it’s Apple or a top law firm or General Mills, we have seen a heightened sense of competition ... It’s pretty staggering how closely law firms watch one another in terms of benefits. If a couple of firms are offering expanded fertility benefits, you’ll start to see that be a fast-moving trend among all law firms. They have incredibly competitive recruitment efforts.”

The Human Rights Campaign, founded in 1980, is the nation’s largest LGBT civil rights organization. The foundation is the educational arm of the group. It started the Corporate Equality Index in 2002, and began including law firms in 2006.