The U.S. Department of Justice filed a civil antitrust lawsuit to block ASSA ABLOY AB?s (ASSA ABLOY) proposed $4.3 billion acquisition of the Hardware and Home Improvement division of its rival, Spectrum Brands Holdings Inc (Spectrum). ASSA ABLOY and Spectrum are two of the three largest producers of residential door hardware in the concentrated, $2.4 billion U.S. industry. If the merger were to go through the DoJ says that Assa Abloy would have a ?near monopoly? on premium mechanical door hardware and more than a 50 percent share in smart locks.