If you're a leading woman equity partner at your firm, odds are you earn significantly less than your male counterparts, according to a survey of more than 1,750 lawyers in 51 countries by the market research firm Acritas.

In survey results released Thursday of equity partners who were independently nominated as ”stars” by senior in-house counsel, Acritas found that the mean average pay for male equity partners in that high-caliber group was 27 percent higher than for female equity partners.

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“It is astonishing to see such a large gender pay gap at the equity partner level. For women that have achieved equity partner status, they should be facing a more equal playing field, but clearly this is not the case,” Acritas CEO Lisa Hart Shepherd said in a statement.

Notably, Acritas found a slightly smaller gender pay gap when comparing median pay, with male equity partners paid 19 percent more than their female counterparts.

But the data showed that “the gap still existed once practice areas had been taken into account,” Shepherd wrote in a follow-up email. A female equity partner working in the same country and practice area, and who made partner in the same year as her male counterpart, could still expect to earn $125,000 less, Acritas reported.

Acritas doesn't have prior years' data that is “sufficiently comparable” to determine if the gap has widened or shrunk in recent years, Shepherd said.

One obstacle to greater pay equity is a bias Acritas has identified in surveys: Women are less likely to be chosen to serve as lead partner on matters, Shepherd said. That trend drags down female partners' compensation because originations are taken into account in more than 80 percent of equity partners' pay, according to Acritas' results.

“Many of these compensation models encourage selfish and self-serving behaviors among 'rain maker' partners,” Shepherd said in an email. “Compensation models that encourage more hunting in packs and team-based relationship management will give opportunities for a more diverse team to be exposed to the client and their expertise showcased.”

It's not that origination should never be taken into account, Shepherd stressed, but firms should take a more “holistic” approach that includes things such as client feedback. “The more factors that are taken into account, the more fair the evaluation of individual contribution is seen to be,” she said.

And, she said, the industry needs to focus on promotions as much as pay.

“The issues go much further than pay alone. The pay gap, as we have shown, exists for like-for-like roles in the same practice areas—but it also arises because firms' cultures have not been conducive to encouraging the development and careers of women,” Shepherd said. “The scarcity of women in the most senior and highly paid roles is not helping this.”