NEW YORK--(BUSINESS WIRE)--Rosen Law Firm, a global investor rights law firm, continues to investigate potential securities claims on behalf of shareholders of National Grid plc (NYSE: NGG) resulting from allegations that National Grid plc may have issued materially misleading business information to the investing public. So What: If you purchased National Grid securities you may be entitled to compensation without payment of any out of pocket fees or costs through a contingency fee arrangement. ...