Same sex marriage. Photo: Diego M. Radzinschi/NLJ

The country’s biggest law firms continue to outperform corporate America in their level of support for lesbian, gay, bisexual, transgender and queer employees.

Of the 160 large firms that participated in this year’s Corporate Equality Index, released Thursday by the Human Rights Campaign Foundation, 127 received perfect scores, up from 112 last year.

“The highly competitive legal field continues to be the sector with the largest number of top-rated employers in the Corporate Equality Index,” said Deena Fidas, the director of the HRC Foundation’s Workplace Equality Program, in a statement. The HRC is the nation’s largest LGBTQ civil rights organization.

Four additional Am Law 200 firms participated this year: Bass, Berry & Sims; Fox Rothschild; Ice Miller; and Reinhart Boerner Van Deuren.

Another 10 firms scored 95 out of 100, while six earned scores of 90 and another 11 earned scores of 85. Only six firms received a score of 80 or below.

“Law firm leaders know that the LGBTQ inclusion is absolutely essential in attracting and retaining top attorneys and staff,” Fidas said.

Compared with the 79 percent of participating law firms, just under half of Fortune 500 companies, 230, achieved a 100 percent ranking—up from 199 companies last year.

The survey, which is voluntary, evaluates the nation’s largest companies and top-grossing law firms, the Am Law 100 and 200, in four areas: nondiscrimination policies based on sexual orientation, gender identity and expression; equitable benefits for LGBTQ workers and their families; LGBTQ education and inclusion programs; and public treatment of the LGBTQ community.

For firms not scoring 100, the most common area by far where they lost points was in not offering transgender-inclusive health insurance. Of the 33 firms scoring less than 100, 19 did not meet that criterion, which is worth 10 points.

Even so, 88 percent of the 160 firms in the survey offer transgender-inclusive health insurance, compared with 58 percent of Fortune 500-ranked companies.

Other areas where firms lost points were not having a firmwide “organizational competency” program (10 points), not having an employee resource group or firmwide diversity council (10 points, or prohibiting discrimination based on sexual orientation but not on gender identity or expression (15 points).

The HRC Foundation started out assessing the basics in 2002, seeing whether companies had nondiscrimination policies. It has progressively placed more emphasis on employee benefits, adding transgender-inclusive health care coverage in 2004. It added organizational competency and public commitment to LGBT issues in 2009.

Two years ago the HRC Foundation started rating businesses on whether they extend nondiscrimination protections to their operations outside the United States, and whether they require outside vendors to follow those policies. It also started looking at whether businesses refuse to donate to groups (except religious organizations) that don’t have written anti-discrimination policies for sexual orientation and gender identity.

Read the full report, along with law firm rankings, here.