Amazon, Apple, Google and Target are among the 379 companies that have signed on to an amicus brief urging the Supreme Court to strike down gay marriage bans.

The highest court on Thursday announced that it would hear a case challenging bans in four states – Ohio, Tennessee, Michigan and Kentucky – on April 28, with a ruling expected in June.

Such bans “hamper employer efforts to recruit and retain the most talented workforce possible in those states,” the companies say in their friend-of-the-court brief.

Gay couples can currently marry in 37 states, plus the District of Columbia. (Conflicting rulings in Alabama have blocked such weddings for now.)

“The burden imposed by inconsistent and discriminatory state laws of having to administer complicated schemes to account for differential treatment of similarly situated employees breeds unnecessary confusion, tension, and diminished employee morale,” the brief states.