David vs Goliath #1: Microsoft loses i4i Patent Case

MICROSOFT CORP. v. i4i LIMITED PARTNERSHIP et al. Case No. 10-290. Decided June 9, 2011

We all love a David vs Goliath story, particularly when it acts as a parable to explain the laws, values and/or morals of society.  This David vs Goliath story seems to show how Patent law is clear and Goliaths such as Microsoft cannot assert patent invalidity without providing compelling evidence. 

Remember the following:

1)      A patent, once issued, grants exclusive rights to its holder, including the exclusive right to use the invention during the patent’s duration;

2)      To enforce a patent right, a patentee can initiate an action for infringement if another party without authority makes, uses, offers to sell, or sells any patented invention.

3)      A patent is presumed valid and the burden of establishing invalidity rests on the party asserting it.

The alleged infringing party can counterclaim invalidity of the patent.  This counterclaim requires alleged infringing party to prove that the patent should not have been issued.


1)      i4i is a software consulting company with a patent claiming an improved method for editing computer documents using a mark-up language that provides a means to display text and tag data, such as an address, using metacode. This was a form of XML.

2)      Microsoft produced a version of Microsoft Word that used XML to mark up editing changes.

3)      i4i sued Microsoft, alleging that Word’s XML editing capabilities infringed the i4i patent.

4)      Microsoft counterclaimed and sought a declaration that the patent was invalid.

Microsoft’s counterclaim was based on the grounds that the i4i product was for sale for over one year prior to filing of the i4i patent application.  Typically, selling a product before filing a patent for it, is a “disclosure” of the invention through public use, and makes the invention unpatentable. In the U.S., there is a grace period of one year, which protects inventors and enables patent protection despite the disclosure – so long as a patent application is filed within the grace period.

i4i argued that the software embodied in the product for sale was different to the invention claimed.

Did Microsoft counterclaim provide sufficient evidence to prove its case?

Microsoft’s argument was based on the absence of analysis: that is, the USPTO’s examiner had not reviewed the i4i’s product on sale when examining the i4i patent.  The argument extended the reasoning to say that if the examiner had considered the i4i product then it could form prior art to destroy the novelty of the i4i patent.  However, the i4i product source code was not available for the early i4i product, so the Microsoft proposition lacked the smoking gun.  Moreover, the Microsoft proposition did not provide clear and convincing evidence but was indirectly arguing invalidity by using the following:

1)      “If” the USPTO had considered the early i4i product as prior art – which is hypothetical since:

  1. the Examiner did not examine this infringing prior art; and
  2. this prior art’s source code is not, and was not available, to support the this argument,

2)      “Then” the novelty of the i4i patent would be destroyed (which was a long shot since the prior art was not available and neither source code nor products would generally be provided during patent examination at the USPTO).

Microsoft did not appear to consider the “or else” argument – that is, any argument that took into consideration the counter situation that if the examiner had considered the i4i product during examination and found that it did not destroy novelty. This is critically important because there is a presumption of validity in favour of the patentee.

Microsoft’s burden to raise evidence to support its claim of invalidity appears to be flawed: Its argument was based on the proposition that:

(a)    if the examiner had hypothetically examined the i4i product

(b)   then it would have found it to have invalidated the patent.

However, this approach left open the else argument, the possibility that if the examiner had examined the i4i product but found that it did not destroy novelty, then the patent would be valid. This finding would be the only finding possible since the only evidence accepted was a hypothetical proposition and thus the presumption of validity would have to fall in favour of the patentee.  Microsoft did try to challenge the “presumption of validity” as having a lower standard; however, such argument was not accepted by the Court.

Microsoft did not establish that the i4i patent should not have been issued, so their counterclaim failed.


  1. MICROSOFT CORP. v. i4i LIMITED PARTNERSHIP et al. Case No. 10-290. Decided June 9, 2011
    Federal Criminal Law Opinions
  2. Microsoft Corp. v. i4i Ltd. Partnership 564 U. S. – 10-290 (2011)
    Justia.com US Supreme Court Center

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