This week, an amicus brief was filed with the US Supreme Court on behalf of 379 American corporations asking the court to make gay marriage legal throughout the country.

An amicus curiae, which means “friend of the court,” is a filing by someone who is not a party to a case but who claims to have a substantial interest in it. It’s considered sidebar advice, and as such, the court is under no obligation to take notice of it. However, many speculate this advice won’t go unnoticed.

When Coca-Cola and PepsiCo both sign the same document urging the court to end discrimination against gay Americans, it’s pretty safe to say that marriage equality has now gone mainstream.

Other companies who have signed on board to support gay marriage include: Amazon, Apple, Dropbox, eBay, Electronic Arts, Facebook, Google, Microsoft, Twitter, Accenture, Aetna, Bank of America, Barclays, Goldman Sachs, AT&T, Bristol-Myers Squibb, Comcast, DirecTV, Dow Chemical, Dupont, GlaxoSmithKline, Pfizer, PriceWaterhouseCoopers, Verizon, Visa, Colgate-Palmolive, ConAgra, General Electric, General Mills, Johnson & Johnson, Kimberly-Clark, Levi Strauss & Co, and the Walt Disney Company.

Even airlines such as Alaska, American, Delta, JetBlue, and United — and three professional sports teams: The New England Patriots, San Francisco Giants, and Tampa Bay Rays — have jumped on the bandwagon.

With a list that extensive (and powerful), even conservatives have to stop and take notice of the growing influence of the gay dollar. It’s unprecedented to see all of these business giants come to total agreement on one issue. But their message is clear.

Inconsistent marriage laws force companies to divert significant time and money to the creation and maintenance of complex administrative systems needed to differentiate treatment of otherwise indistinguishable employees based on the different marriage laws of the places where they live. These differences can create rifts in the employer-employee relationship. Employers are better served by a uniform marriage rule that gives equal dignity to employee relationships. Allowing same-sex couples to marry improves employee morale and productivity, reduces uncertainty, and removes the wasteful administrative burdens imposed by the current disparity of state law treatment.

Legally, this is a smart move.

Instead of debating value systems, they are weighing in from their business perspective and making one undeniable statement: Bigotry against the LGBT community is simply bad for American business.