 Shares of Spectrum Brands Holdings Inc. SPB, -8.93 dove 8.6 in morning trading Thursday toward a two-year low, after the U.S. Department of Justice sued to block the branded consumer products companys sale of its hardware and home improvement HHI business to Sweden-based Assa Abloy AB ASAZY, 2.56 ASSA.B, 2.43 amid competition concerns. Spectrum responded by saying the DOJs opposition of the sale was baseless, and ignores the realities of the residential security marketplace, which has many capable and vigorous competitors and easy entry by new firms. 