The US Supreme Court has backed US sportswear giant Nike in a trademark ruling against smaller rival Already LLC, maker of Yums athletic shoes.

In a case that goes back to 2009, Nike had alleged that two of Already's athletic shoes violated its Air Force 1 trademark.

Already denied the allegations and filed a counterclaim challenging the validity of Nike's Air Force 1 trademark.

This prompted Nike to issue a covenant promising not to sue or raise any trademark or unfair competition claims against Already's existing footwear designs, or any future designs based on its current products.

Already refused to agree that the covenant had extinguished the case or controversy, arguing that its business was threatened and potential backers would not consider investing in Already until Nike's trademark was invalidated.

But both the District Court and Second Circuit dismissed Already's counterclaim, concluding that there was no longer a justiciable controversy.

Accprding to court documents, the court said it could not conceive of a shoe that would infringe Nike's trademark yet not fall within the covenant; and that Already had not asserted any intent to market such a shoe.