On December 22, 2021, a unanimous Pennsylvania Supreme Court held in Robert Mallory v. Norfolk Southern Railway Company that a foreign corporation is not subject to personal jurisdiction in the Commonwealth of Pennsylvania solely because of its registration to do business there. The Mallory decision is an affirmation of the due process rights of non-Pennsylvania corporate defendants and significantly impacts who can permissibly be sued in the Commonwealth. Mallory, a resident of the Commonwealth of Virginia, filed suit in Pennsylvania seeking damages under the Federal Employers’ Liability Act against his former employer, Norfolk Southern, a Virginia corporation, for injuries allegedly sustained in the course of the plaintiff’s work in Virginia and Ohio. The sole basis for the exercise of personal jurisdiction was Norfolk Southern’s registration to do business in the Commonwealth of Pennsylvania. Pennsylvania’s business registration statute is unique in that the statute conditions registration upon a corporation’s “consent” to personal jurisdiction in Pennsylvania courts. Before Mallory, Pennsylvania state courts and many of Pennsylvania’s federal courts generally permitted the exercise of personal jurisdiction over foreign corporations based solely on their registering to do business in Pennsylvania. The appeal in Mallory required the Pennsylvania Supreme Court to consider whether Pennsylvania’s broad exercise of personal jurisdiction through its corporate registration statute comports with the demands of due...