Ernst & Young LLP and its affiliates will join an increasing number of employers in reimbursing LGBT employees for the additional federal and state taxes they incur for their same-sex domestic partners’ medical benefits. in the U.S. Ernst & Young is the first Big Four accounting firm to offer this perk.

Under federal law and many states’ laws, same-sex couples are burdened with extra taxes when their partners are covered by health insurance since many states do not recognize same-sex partnerships. The extra taxes are mandated even for married same-sex couples, costing lesbian and gay employees an average of $1,500 in extra taxes annually. Married heterosexual couples are exempt from these taxes, likely the reason why many companies are now taking this stand to provide equitable benefits.

According to the Human Rights Campaign (HRC), there were only 30 for-profit employers that provided these tax equalization benefits as of December 2011.