The U.S. Supreme Court on Monday declined to hear a case that sought to block the U.S. Department of Justice from reopening a probe into the National Association of Realtors over the commissions brokers charge on home sales.

The court's refusal to take the case prolongs uncertainty over what new standards for agents' commissions will satisfy DOJ's concerns over what it considers "anticompetitive" practices in the real estate industry.

The US Supreme Court turned away an appeal by the National Association of Realtors, leaving intact a ruling that lets the Justice Department restart an antitrust probe into the organization’s policies.