The Biden Justice Department took the unprecedented step this past summer of nixing a proposed settlement with the National Association of Realtors because the deal, agreed to in the waning days of the Trump administration, didn’t go far enough in cracking down on the association’s anti-competitive practices.

Now, the association is crying foul, arguing that the DOJ is barred from digging deeper. In pushing back, the NAR revealed that the DOJ recently served it with a civil subpoena. At the heart of the new investigation: the tens of billions of dollars that U.S. consumers pay to buy and sell homes.