A preliminary injunction is a court-ordered injunction that issues prior to a final ruling, generally issued to restrain the defendant from engaging in allegedly infringing conduct. Preliminary injunctions are not typical– a court will grant an injunction only when clearly warranted.
It is well-established that a preliminary injunction is an extraordinary remedy reserved only for those cases where it is clearly warranted.
— Apple, Inc. v. Samsung Electronics Co., Ltd., 678 F. 3d 1314, 1334 (Fed. Cir. 2012).
A preliminary injunction may be warranted for a number of reasons:
It may preserve the relative positions of parties until trial.
As the Court has explained, [t]he purpose of a preliminary injunction is merely to preserve the relative positions of the parties until a trial on the merits can be held.
— Kimberly-Clark v. First Quality Baby Products, 660 F. 3d 1293, 1299 (Fed. Cir. 2011).
It may provide speedy relief from irreparable harm.
A requirement of oral testimony would in effect require a full hearing on the merits and would thus defeat one of the purposes of a preliminary injunction which is to give speedy relief from irreparable injury.
— Ross-Whitney Corp. v. Smith Kline & French Lab., 207 F. 2d 190, 198 (9th Cir. 1953).
A patentee must establish four factors in order to win a motion for preliminary injunction.
When ruling on a motion for a preliminary injunction, a district court must consider and analyze four factors: (1) whether the movant is likely to succeed on the merits; (2) whether the movant is likely to suffer irreparable harm in the absence of injunctive relief; (3) the balance of hardships; and (4) whether issuance of an injunction is in the public interest.
— Apple, Inc. v. Samsung Electronics Co., Ltd., 678 F. 3d 1314, 1335 (Fed. Cir. 2012).
The last three factors are essentially the same as the factors considered in granting a permanent injunction.
[T]he Supreme Court has explained that the standard for a preliminary injunction is essentially the same as for a permanent injunction with the exception that the plaintiff must show a likelihood of success on the merits rather than actual success.
— Apple Inc. v. Samsung Electronics Co., Ltd., 735 F. 3d 1352, 1361 (Fed. Cir. 2013).
The first factor requires the patentee to show that a finding of validity and infringement is likely.
With regard to the first factor — establishing a likelihood of success on the merits — the patentee seeking a preliminary injunction in a patent infringement suit must show that it will likely prove infringement, and that it will likely withstand challenges, if any, to the validity [and enforcability] of the patent.
— Titan Tire Corp. v. Case New Holland, Inc., 566 F. 3d 1372, 1376 (Fed. Cir. 2009)
In cases where the infringer does not challenge validity it is enough to establish likelihood of success with respect to infringement.
Thus, if a patentee moves for a preliminary injunction and the alleged infringer does not challenge validity, the very existence of the patent with its concomitant presumption of validity satisfies the patentee's burden of showing a likelihood of success on the validity issue.
— Titan Tire Corp. v. Case New Holland, Inc., 566 F. 3d 1372, 1377 (Fed. Cir. 2009).
With a preliminary injunction, likelihood of success can be a deciding factor in evaluating the public interest inquiry.
As this court has recognized, [a]lthough the public interest inquiry is not necessarily or always bound to the likelihood of success o[n] the merits, ... absent any other relevant concerns ... the public is best served by enforcing patents that are likely valid and infringed.
— Apple, Inc. v. Samsung Electronics Co., Ltd., 678 F. 3d 1314, 1338 (Fed. Cir. 2012).
See the chapter on permanent injunction for more discussion.