More than 200 major U.S. and international corporations signed an amicus brief submitted to the Supreme Court on Tuesday arguing that excluding sexual orientation and gender identity from federal civil rights law “would undermine the nation’s business interests.”

“The 206 businesses that join this brief as amici collectively employ over 7 million employees, and comprise over $5 trillion in revenue,” the brief states. “These businesses — which range across a wide variety of industries (and some of which are even competitors) — share a common interest in equality because they know that ending discrimination in the workplace is good for business, employees, and the U.S. economy as a whole.”

The brief, filed by several LGBTQ-rights groups, argues that LGBTQ people deserve to share in the fruits of a free market economy, with “the opportunity to earn a living, excel in their professions, and provide for their families free from fear of unequal treatment.”

The signatories include Airbnb, Amazon, American Airlines, Apple, Bayer, Bank of America, Best Buy, Domino’s, Facebook, GM, Google, Hilton, IBM, JP Morgan Chase, Marriott, Macy’s, Morgan Stanley, Nike and Comcast-NBCUniversal, the parent company of NBC News. According to the Human Rights Campaign, one of the LGBTQ advocacy groups behind the brief, said it “has more corporate signers than any previous business brief in an LGBTQ nondiscrimination case.”

The brief comes before the high court hears arguments Oct. 8 in three cases involving LGBTQ workplace discrimination. In Altitude Express v. Zarda, a skydiving instructor was fired after a customer complained that the instructor disclosed that he is gay. In R.G. & G.R. Harris Funeral Homes v. EEOC and Aimee Stephens, a trans woman was fired from her long-time job at a funeral home after she announced her gender transition. And in Bostock v. Clayton County, a man was fired from his job as a county child welfare services coordinator after his employer learned he is gay.

While lower courts ruled in favor of the employees in the first two cases, the 11th U.S. Circuit Court of Appeals ruled in favor of the employer in the Bostock case, setting up incongruity between the lower courts, and thus, a Supreme Court review. The high court justices are expected to rule on whether workplace discrimination based on one’s sexual orientation or gender identity violates Title VII of the Civil Rights Act of 1964, which “prohibits employment discrimination based on race, color, religion, sex and national origin.”

The Alliance Defending Freedom, a conservative Christian legal group known for advocating against LGBTQ rights, is arguing for the court to reverse lower courts’ expanding definition of sex discrimination.

“Substituting ‘gender identity’ for ‘sex’ in nondiscrimination laws also threatens freedom of conscience,” the ADF’s petition reads. “Statutes interpreted that way have the effect, for instance, of forcing doctors to participate in — or employers to pay for — surgical efforts to alter sex in violation of their deeply held beliefs….”

Without a federal law explicitly banning workplace discrimination based on sexual orientation and gender identity, a number of states across the United States have passed their own measures to outlaw such discrimination. However, it is currently legal in 26 states to fire someone solely due to their sexual orientation or gender identity, according to the Movement Advancement Project, an LGBTQ think tank.

Should the Supreme Court side with the LGBTQ employees in the three cases at hand, discriminating against an employee due to their sexual orientation or gender identity would become illegal under federal civil rights law.

FOLLOW NBC OUT ON TWITTER, FACEBOOK & INSTAGRAM