concurring.
I join the Court’s opinion. I deem it appropriate, however, to add a few comments to what my Brother Clark has written because the issue decided is one of first impression and to allay possible misapprehension as to the possible reach of this decision.
We hold today that a treble-damage action for monopolization which, but for the existence of a patent, would be violative of § 2 of the Sherman Act may be maintained under § 4 of the Clayton Act if two conditions are satisfied: (1) the relevant patent is shown to have been procured by knowing and willful fraud practiced by the defendant on the Patent Office or, if the defendant was not the original patent applicant, he had been enforcing the patent with knowledge of the fraudulent manner in which it was obtained; and (2) all the elements otherwise necessary to establish a § 2 monopolization charge are proved. Conversely, such a private cause of action would not be made out if the plaintiff: (1) showed no more than invalidity of the patent arising, for example, from a judicial finding of “obviousness,” or from other factors sometimes compendiously referred to as “technical fraud”; or (2) showed fraudulent procurement, but no knowledge thereof by the defendant; or (3) failed to prove the elements of a § 2 charge even though he has established actual fraud in the procurement of the patent and the defendant’s knowledge of that fraud.
It is well also to recognize the rationale underlying this decision, aimed of course at achieving a suitable accommodation in this area between the differing policies of the patent and antitrust laws. To hold, as we do, that private suits may be instituted under § 4 of the Clayton Act to recover damages for Sherman Act monopolization knowingly practiced under the guise of a patent *180procured by deliberate fraud, cannot well be thought to impinge upon the policy of the patent laws to encourage inventions and their disclosure. Hence, as to this class of improper patent monopolies, antitrust remedies should be allowed room for full play. On the other hand, to hold, as we do not, that private antitrust suits might also reach monopolies practiced under patents that for one reason or another may turn out to be voidable under one or more of the numerous technicalities attending the issuance of a patent, might well chill the disclosure of inventions through the obtaining of a patent because of fear of the vexations or punitive consequences of treble-damage suits. Hence, this private antitrust remedy should not be deemed available to reach § 2 monopolies carried on under a nonfraudulently procured patent.
These contrasting factors at once serve to justify our present holding and to mark the limits of its application.