Microsoft Corp. v. i4i Ltd. Partnership

Microsoft Corp. v. i4i Ltd. Partnership, 564 U.S. 91 (2011), was a case decided by the Supreme Court of the United States. It deals with the presumption of validity and the standard of evidence in patent lawsuits. This case in widely considered as a prime example of a frivolous lawsuit by a patent troll, underscoring the need for a reform of the US patent law.[1]

Microsoft Corp. v. i4i Ltd. Partnership
Argued April 18, 2011
Decided June 9, 2011
Full case nameMicrosoft Corp. v. i4i Ltd. Partnership
Docket no.10-290
Citations564 U.S. 91 (more)
131 S. Ct. 2238; 180 L. Ed. 2d 131; 2011 U.S. LEXIS 4376; 79 U.S.L.W. 4454; 98 U.S.P.Q.2d 1857
Court membership
Chief Justice
John Roberts
Associate Justices
Antonin Scalia · Anthony Kennedy
Clarence Thomas · Ruth Bader Ginsburg
Stephen Breyer · Samuel Alito
Sonia Sotomayor · Elena Kagan
Case opinions
MajoritySotomayor, joined by Scalia, Kennedy, Ginsburg, Breyer, Alito, Kagan
ConcurrenceBreyer, joined by Scalia, Alito
ConcurrenceThomas (in judgment)
Roberts took no part in the consideration or decision of the case.

The case was a patent dispute between small Toronto-based company i4i Ltd. Partnership and Microsoft for infringement of a patent regarding custom XML encoding in Microsoft Word, a feature that was “used by only a small fraction of Microsoft’s customers”.[2] The original lawsuit was filed in the Federal Court for the Eastern District of Texas, known for its decisions favoring patent trolls. i4i prevailed both in the district court and on appeal to the CAFC. The latter awarded i4i $200 million against Microsoft as a reasonable royalty.

Under 35 U.S.C. § 282, a patent, which has been examined and issued by the USPTO is entitled to a presumption of validity in courts, and this presumption can be overcome based on clear and convincing evidence.[3]

On appeal to the SCOTUS Microsoft argued that the clear and convincing evidence standard applied by the Federal Circuit was inappropriate, and that because of the backlog of unexamined patent applications at the USPTO, patent examiners do not have adequate amount of time to examine patent applications, and therefore a preponderance of the evidence standard should be applied by courts, when patent validity is challenged.

The US Supreme Court rejected Microsoft's position.[4] Judge Sotomayor wrote: "Congress has amended the patent laws to account for concerns about 'bad' patents, including by expanding the reexamination process to provide for inter partes proceedings. Through it all the evidentiary standard adopted in §282 has gone untouched."[5]

The courts also issued and confirmed a permanent injuction against Microsoft. The disputed feature has been removed from Word since.


  1. ^ Reconsidering the georgia-pacific standard for reasonable royalty patent damages. 2010. BYU L Rev. 1661. C.B. Seaman.
  2. ^
  3. ^ Microsoft Corp. v. i4i Ltd. Partnership, 564 U.S. 91 (2011).
  4. ^ Liptak, Adam (June 10, 2011). "Microsoft Loses Appeal in i4i Patent Case". The New York Times. Retrieved July 3, 2018.
  5. ^

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