Covad Communications, a digital subscriber line (DSL) provider, filed a registration statement with the Securities and Exchange Commission for its previously announced secondary offering. Covad will make 7.5 million shares available, and 1.125 common shares will be subject to an underwriters' over-allotment option. Bear Stearns, Morgan Stanley Dean Witter, BT Alex. Brown, Credit Suisse First Boston, Donaldson Lufkin & Jenrette and Wit Capital are the managing underwriters of the offering.