Rock-Tenn Company and MeadWestvaco Corporation today announced that the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 with respect to the pending business combination transaction between RockTenn and MWV has expired. The 30-day waiting period is required by the Federal Trade Commission and U.S. Department of Justice as part of the premerger notification program before such a combination transaction can close.