I4I v. Microsoft ( 2010 )


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  •   United States Court of Appeals for the Federal Circuit
                                            2009-1504
    
                              I4I LIMITED PARTNERSHIP and
                        INFRASTRUCTURES FOR INFORMATION INC.,
    
                                                          Plaintiffs-Appellees,
    
                                                 v.
    
                                 MICROSOFT CORPORATION,
    
                                                          Defendant-Appellant.
    
    
           Donald R. Dunner, Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P., of
    Washington, DC, argued for plaintiffs-appellees. With him on the brief were Don O.
    Burley, Kara F. Stoll and Jason W. Melvin; and Erik R. Puknys, of Palo Alto, California. Of
    counsel on the brief were Douglas A. Cawley and Jeffrey A. Carter, McKool Smith, P.C. of
    Dallas, Texas, and T. Gordon White, of Austin, Texas.
    
          Matthew D. Powers, Weil, Gotshal & Manges LLP, of Redwood Shores, California,
    argued for defendant-appellant. With him on the brief were Kevin S. Kudlac and Amber H.
    Rovner, of Austin, Texas. Of counsel on the brief were Matthew D. McGill, Minodora D.
    Vancea, Gibson, Dunn & Crutcher LLP, of Washington, DC; and Isabella E. Fu, Microsoft
    Corporation, of Redmond, Washington. Of counsel was David J. Lender, Weil, Gotshal &
    Manges LLP, of New York, New York.
    
           John W. Thornburgh, Fish & Richardson, P.C., of San Diego, California, for amici
    curiae Dell Inc. and Hewlett-Packard Company. With him on the brief were John E.
    Gartman; and Indranil Mukerji, of Washington, DC.
    
           Richard A. Samp, Washington Legal Foundation, of Washington, DC, for amicus
    curiae Washington Legal Foundation, of Washington, DC. With him on the brief was
    Daniel J. Popeo.
    
    Appealed from: United States District Court for the Eastern District of Texas
    
    Judge Leonard Davis
     United States Court of Appeals for the Federal Circuit
                                            2009-1504
    
                              I4I LIMITED PARTNERSHIP and
                        INFRASTRUCTURES FOR INFORMATION INC.,
    
                                                      Plaintiffs-Appellees,
    
                                                 v.
    
                                 MICROSOFT CORPORATION,
    
                                                      Defendant-Appellant.
    
    Appeal from the United States District Court for the Eastern District of Texas in case no.
    07-CV-113, Judge Leonard Davis.
    
                                __________________________
    
                                DECIDED: March 10, 2010
                                __________________________
    
    
    Before SCHALL, PROST, and MOORE, Circuit Judges.
    
    PROST, Circuit Judge.
    
           This is a patent infringement case about an invention for editing custom XML, a
    
    computer language. The owner of the patent, i4i Limited Partnership (“i4i”), brought suit
    
    against Microsoft Corporation (“Microsoft”), alleging that the custom XML editor in
    
    certain versions of Microsoft Word (“Word”), Microsoft’s word-processing software,
    
    infringed i4i’s patent. After a seven-day trial, the jury found Microsoft liable for willful
    
    infringement. The jury rejected Microsoft’s argument that the patent was invalid, and
    
    awarded $200 million in damages to i4i. The district court denied Microsoft’s motions
    
    for judgment as a matter of law and motions for a new trial, finding that Microsoft had
    
    waived its right to challenge, among other things, the validity of the patent based on all
    but one piece of prior art and the sufficiency of the evidence supporting the jury’s
    
    damage award.      Although statutorily authorized to triple the jury’s damages award
    
    because of Microsoft’s willful infringement, the district court awarded only $40 million in
    
    additional damages.     It also granted i4i’s motion for a permanent injunction.        This
    
    injunction, which this court stayed pending the outcome of this appeal, is narrow. i4i
    
    Ltd. v. Microsoft Corp., No. 2009-1504 (Fed. Cir. Sept. 3, 2009). It does not affect
    
    copies of Word sold or licensed before the injunction goes into effect. Thus, users who
    
    bought or licensed Word before the injunction becomes effective will still be able to use
    
    the infringing custom XML editor, and receive technical support from Microsoft. After its
    
    effective date, the injunction prohibits Microsoft from selling, offering to sell, importing,
    
    or using copies of Word with the infringing custom XML editor.            Microsoft is also
    
    prohibited from instructing or assisting new customers in the custom XML editor’s use.
    
           On appeal, Microsoft challenges the jury verdict and injunction on multiple
    
    grounds. Because this case went to trial and we are in large part reviewing what the
    
    jury found, our review is limited and deferential.        We affirm the issuance of the
    
    permanent injunction, though we modify its effective date to accord with the evidence.
    
    In all other respects, we affirm for the reasons set forth below.
    
                                         BACKGROUND
    
           i4i began as a software consulting company in the late 1980s.              Basically,
    
    companies would hire i4i to develop and maintain customized software for them. Thus,
    
    while consumers might not find i4i’s products on the shelves at Best Buy or CompUSA,
    
    i4i was in the business of actively creating, marketing, and selling software. In June
    
    1994, i4i applied for a patent concerning a method for processing and storing
    
    
    
    
    2009-1504                                    2
    information about the structure of electronic documents. After approximately four years,
    
    the United States Patent and Trademark Office (“PTO”) allowed the application, which
    
    issued as U.S. Patent No. 5,787,449 (“’449 patent”). The invention claimed in the ’449
    
    patent forms the basis of this litigation. Since then, i4i has developed several software
    
    products that practice the invention. One of these products is “add-on” software for
    
    Microsoft Word, which expands Word’s capability to work with documents containing
    
    custom XML.
    
           XML is one of many markup languages. Markup languages tell the computer
    
    how text should be processed by inserting “tags” around text. Tags give the computer
    
    information about the text. For example, some tags might tell the computer how to
    
    display text, such as what words should appear in bold or italics. Tags can also tell the
    
    computer about the text’s content, identifying it as a person’s name or social security
    
    number, for instance. Each tag consists of a delimiter and tag name. The delimiter sets
    
    the tag apart from the content. Thus, a tag indicating that “717 Madison Pl. NW” is an
    
    address might appear as 717 Madison Pl. NW where “address” is
    
    the tag’s name and “<” and “>” are the delimiters. Custom XML allows users to create
    
    and define their own tags. i4i refers to tags and similar information about a document’s
    
    structure as “metacodes.” The specification of the ’449 patent defines “metacode” as
    
    “an individual instruction which controls the interpretation of the content of the data.”
    
    ’449 patent col.4 ll.15-16.
    
           The ’449 patent claims an improved method for editing documents containing
    
    markup languages like XML.       The improvement stems from storing a document’s
    
    content and metacodes separately.       Id. at col.6 ll.18-21.   The invention primarily
    
    
    
    
    2009-1504                                  3
    achieves this separation by creating a “metacode map,” a data structure that stores the
    
    metacodes and their locations within the document. The document’s content is stored
    
    in a data structure called “mapped content.” Claim 14 is illustrative:
    
           A method for producing a first map of metacodes and their addresses of
           use in association with mapped content and stored in distinct map storage
           means, the method comprising:
    
           providing the mapped content to mapped content storage means;
    
           providing a menu of metacodes; and
    
           compiling a map of the metacodes in the distinct storage means, by
           locating, detecting and addressing the metacodes; and
    
           providing the document as the content of the document and the metacode
           map of the document.
    
    Id. at col.16 ll.18-30.
    
           Separate storage of a document’s structure and content was an improvement
    
    over prior technology in several respects. Importantly, it has allowed users to work
    
    solely on a document’s content or its structure. Id. at col.7 ll.6-11, 17-20.
    
           Since 2003, versions of Microsoft Word, a word processing and editing software,
    
    have had XML editing capabilities. In 2007, i4i filed this action against Microsoft, the
    
    developer and seller of Word. i4i alleged that Microsoft infringed claims 14, 18, and 20
    
    of the ’449 patent by making, using, selling, offering to sell, and/or importing Word
    
    products capable of processing or editing custom XML.              i4i further alleged that
    
    Microsoft’s infringement was willful. Microsoft counterclaimed, seeking a declaratory
    
    judgment that the ’449 patent was invalid and unenforceable.
    
           Before the case was submitted to the jury, Microsoft moved for judgment as a
    
    matter of law (“JMOL”) on the issues of infringement, willfulness, and validity. The
    
    
    
    
    2009-1504                                    4
    district court denied Microsoft’s motions, and the case was submitted to the jury. The
    
    jury found that Word infringed all asserted claims of the ’449 patent. The jury further
    
    found that the patent was not invalid, and that Microsoft’s infringement was willful. It
    
    awarded $200 million in damages.
    
          After trial, Microsoft renewed its motions for JMOL on infringement, validity, and
    
    willfulness. In the alternative, Microsoft moved for a new trial on these issues based on
    
    the sufficiency of the evidence supporting the jury’s findings. Microsoft also argued it
    
    was entitled to a new trial based on errors in the claim construction, evidentiary rulings,
    
    and jury instructions. The district court denied Microsoft’s motions. It granted i4i’s
    
    motion for a permanent injunction and awarded $40 million in enhanced damages.
    
          Microsoft now appeals. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).
    
                                          DISCUSSION
    
          Microsoft raises numerous issues on appeal.         First, Microsoft challenges the
    
    district court’s construction of the claim term “distinct.” Second, Microsoft challenges
    
    the jury’s validity finding, urging us to find that the ’449 patent was anticipated or
    
    obvious as a matter of law, or at least grant a new trial on those issues. Third, Microsoft
    
    argues that the jury’s infringement finding must be set aside because it is unsupported
    
    by substantial evidence. Fourth, Microsoft challenges the damages award, specifically
    
    the admission of certain expert testimony and the sufficiency of the evidence supporting
    
    the award. Finally, Microsoft challenges the issuance and terms of the permanent
    
    injunction. We address each of these issues in turn.
    
    
    
    
    2009-1504                                   5
                                      I. Standards of Review
    
           For issues not unique to patent law, we apply the law of the regional circuit in
    
    which this appeal would otherwise lie. Thus, we apply Fifth Circuit law when reviewing
    
    evidentiary rulings and denials of motions for JMOL or new trial.          Finisar Corp. v.
    
    DirecTV Group, Inc., 
    523 F.3d 1323
    , 1328 (Fed. Cir. 2008).
    
           We review denials of JMOL de novo.          Cambridge Toxicology Group, Inc. v.
    
    Exnicios, 
    495 F.3d 169
    , 179 (5th Cir. 2007). JMOL is appropriate only if the court finds
    
    that a “reasonable jury would not have a legally sufficient evidentiary basis to find for the
    
    party on that issue.” Fed. R. Civ. P. 50(a)(1); see Cambridge Toxicology, 495 F.3d at
    
    179.
    
           We review the denial of a new trial motion for abuse of discretion. Industrias
    
    Magromer Cueros y Pieles S.A. v. La. Bayou Furs Inc., 
    293 F.3d 912
    , 924 (5th Cir.
    
    2002). We will not reverse a denial absent a “clear showing” of an “absolute absence of
    
    evidence to support the jury’s verdict.” Duff v. Werner Enters., Inc., 
    489 F.3d 727
    , 729
    
    (5th Cir. 2007) (emphasis added).
    
           We review jury instructions for abuse of discretion, cognizant as we do so of the
    
    district court’s broad discretion to compose jury instructions, so long as the instructions
    
    accurately describe the law. Baker v. Canadian Nat’l/Ill. Cent. R.R., 
    536 F.3d 357
    , 363-
    
    64 (5th Cir. 2008); Walther v. Lone Star Gas Co., 
    952 F.2d 119
    , 125 (5th Cir. 1992); see
    
    also Barton’s Disposal Serv., Inc. v. Tiger Corp., 
    886 F.2d 1430
    , 1434 (5th Cir. 1989).
    
    We will reverse a judgment “only if the [jury instructions] as a whole create[] a
    
    substantial doubt as to whether the jury has been properly guided in its deliberations.”
    
    Baker, 536 F.3d at 363-64. Erroneous instructions are subject to harmless error review.
    
    
    
    
    2009-1504                                    6
    We will not reverse if, considering the record as a whole, the erroneous instruction
    
    “could not have affected the outcome of the case.” Wright v. Ford Motor Co., 
    508 F.3d 263
    , 268 (5th Cir. 2007).
    
                                      II. Claim Construction
    
           On appeal, we must decide whether the district court properly construed the
    
    claim term “distinct.” In the asserted claims, the term “distinct” is used to describe how
    
    the metacode map and the mapped content are stored. Specifically, the claims say the
    
    metacode map is stored in “distinct map storage means” or “distinct storage means.”
    
    See, e.g., ’449 patent col.16 ll.20, 25-26, 53-54. Analogously, the document’s content is
    
    stored in “mapped content storage,” id. at col.16 ll.22-23, or “mapped content distinct
    
    storage means.” Id. at col.15 l.51 (emphasis added).
    
           Before the district court, Microsoft argued that “distinct” added two requirements:
    
    (1) storing the metacode map and mapped content in separate files, not just separate
    
    portions of the computer’s memory; and (2) the ability to edit the document’s content
    
    and its metacode map “independently and without access” to each other.
    
           The district court rejected both of Microsoft’s proposed limitations. Based on its
    
    review of the claim language, the specification, and prosecution history, the district court
    
    concluded that “distinct” did not require storage in separate files. Similarly, it concluded
    
    that the user’s ability to independently edit the document’s structure or content was a
    
    benefit of separate storage, not a claim limitation.       The district court then defined
    
    “distinct map storage means” in more general terms, as “a portion of memory for storing
    
    a metacode map.” “Mapped content distinct storage means” was defined as “a portion
    
    of memory for storing mapped content.”
    
    
    
    
    2009-1504                                    7
           On appeal, Microsoft renews both arguments about the meaning of “distinct.”
    
    We review the district court’s claim construction de novo. Cybor Corp. v. FAS Techs.,
    
    Inc., 
    138 F.3d 1448
    , 1454-55 (Fed. Cir. 1998) (en banc). To ascertain the scope and
    
    meaning of the asserted claims, we look to the words of the claims themselves, the
    
    specification, and the prosecution history. Phillips v. AWH Corp., 
    415 F.3d 1303
    , 1315-
    
    17 (Fed. Cir. 2005) (en banc); see also 35 U.S.C. § 112 ¶ 2; Innova/Pure Water, Inc. v.
    
    Safari Water Filtration Sys., Inc., 
    381 F.3d 1111
    , 1115-16 (Fed. Cir. 2004) (holding that
    
    the claims are not “presumed” to be restricted to the embodiments disclosed in the
    
    specification). We conclude that the district court properly rejected both of Microsoft’s
    
    proposed limitations.
    
                                        A. Separate Files
    
           To determine whether “distinct” adds the requirement of storage in separate files,
    
    we begin with the claim language. See Phillips, 415 F.3d at 1312. In this case, the
    
    claim’s plain language does not require storage of the metacode map and mapped
    
    content in separate files. The term “file” appears nowhere in the ’449 patent. Instead,
    
    the claims use “storage means”; the specification uses “structures.” ’449 patent col.16
    
    ll.22-26, 53; see also id. at col.4 ll.7-13, 21-24. Both “storage means” and “structures”
    
    are broader terms than “file,” suggesting no particular format.       At trial, i4i’s expert
    
    testified that a person of ordinary skill in the art would understand “structures” to store
    
    and organize data, but not as limited to a particular storage format.         Indeed, the
    
    specification arguably renounces particular formats by defining “document” as a “non-
    
    random aggregation of data irrespective of its mode of storage or presentation.” Id. at
    
    col.4 ll.57-59 (emphasis added).
    
    
    
    
    2009-1504                                   8
           Turning to the specification, we similarly see no “clear intent[] to limit the claim
    
    scope” to storage in files. Abbott Labs. v. Sandoz, Inc., 
    566 F.3d 1282
    , 1288 (Fed. Cir.
    
    2009). The sample algorithms do not say the storage means is restricted to “files.” ’449
    
    patent col.8 ll.53-62; see Innova/Pure Water, 381 F.3d at 1121-22. Instead, they use
    
    the more generic term “storage space,” creating one for the mapped content and
    
    another for the metacode map.
    
           As for the prosecution history, we do not read it as limiting storage to files.
    
    During prosecution, i4i distinguished its invention from U.S. Patent No. 5,280,574
    
    (“Mizuta”) prior art in part because Mizuta stored “all document information . . . in one
    
    file . . . the document file.” But this is not all i4i said. i4i then explained that Mizuta
    
    “lacked any notion of a metacode map” or “distinct storage means.”           In evaluating
    
    whether a patentee has disavowed claim scope, context matters.            Together, these
    
    statements make clear that what distinguished the Mizuta prior art was not the storage
    
    type (file or no file), but rather the separation of a document’s content and structure.
    
    The statements Microsoft now plucks from the prosecution history do not “clear[ly] and
    
    unmistakabl[y] disavow” storage means that are not files. Computer Docking Station
    
    Corp. v. Dell, Inc., 
    519 F.3d 1366
    , 1374 (Fed. Cir. 2008) (citing Purdue Pharma L.P. v.
    
    Endo Pharms., Inc., 
    438 F.3d 1123
    , 1136 (Fed. Cir. 2006)).
    
           Because the claims themselves do not use the word “file” and the specification
    
    discloses embodiments where the storage format is not a file, we conclude that “distinct”
    
    does not require storage in separate files. Liebel-Flarsheim Co. v. Medrad, Inc., 
    358 F.3d 898
    , 907-08 (Fed. Cir. 2004) (declining to limit the invention’s scope to the
    
    disclosed embodiments when the specification did “not expressly or by clear implication
    
    
    
    
    2009-1504                                   9
    reject the scope of the invention” to those embodiments); see also Boston Scientific
    
    Scimed, Inc. v. Cordis Corp., 
    554 F.3d 982
    , 987 (Fed. Cir. 2009).
    
                                      B. Independent Manipulation
    
           The closer question is whether “distinct” requires independent manipulation of
    
    the metacode map and mapped content. Several of the embodiments in the ’449 patent
    
    allow the user to manipulate only the metacode map or mapped content. ’449 patent
    
    figs.4, 5, 6, 8. However, based on our review of the claim language, the specification,
    
    and the prosecution history, we conclude that the claims are not limited to these
    
    particular embodiments.
    
           Generally, a claim is not limited to the embodiments described in the
    
    specification unless the patentee has demonstrated a “clear intention” to limit the claim’s
    
    scope with “words or expressions of manifest exclusion or restriction.”            Liebel-
    
    Flarsheim, 358 F.3d at 906; see also Teleflex, Inc. v. Ficosa N. Am. Corp., 
    299 F.3d 1313
    , 1327 (Fed. Cir. 2002). By the same token, not every benefit flowing from an
    
    invention is a claim limitation.      See Computer Docking, 519 F.3d at 1374; Verizon
    
    Servs. Corp. v. Vonage Holding Corp., 
    503 F.3d 1295
    , 1302-03 (Fed. Cir. 2007).
    
           We begin again with the claim language.             None of the claims mention
    
    “independent manipulation” of the mapped content and metacode map, an omission we
    
    find significant. Had the inventors intended this limitation, they could have drafted the
    
    claims to expressly include it.
    
           Similarly, the specification refers to “separate,” rather than “independent,”
    
    manipulation of the document’s architecture and content. The specification goes on to
    
    describe the storage of the metacode map and content as “distinct and separate.”
    
    
    
    
    2009-1504                                     10
    “Distinct” and “separate” are not the same as “independent.”                Moreover, the
    
    specification teaches that “separate manipulation” describes the user’s ability to work on
    
    only the metacode map or content.          Behind the scenes, the invention keeps the
    
    metacode map and content synchronized. For example, Figure 9 teaches that updates
    
    to the content may require the invention to make corresponding changes to the
    
    metacode map. ’449 patent col.14 l.49-col.15 l.5.
    
           Microsoft is correct that the specification refers to working on “solely” the
    
    document’s structure (metacode map):
    
               The present invention provides the ability to work solely on metacodes.
           The process allows changes to be made to the structure of a document
           without requiring the content. A metacode map could be edited directly
           without the mapped content. Additionally a new map can be created
           based solely on an existing map without requiring the content.
    
    Id. at col.7 ll.6-11 (emphases added). Read as a whole, however, these statements are
    
    best understood as describing the advantages of separate storage, the real claim
    
    limitation.   See Abbott Labs., 566 F.3d at 1289-90.         The specification’s permissive
    
    language, “could be edited,” “can be created,” and “ability to work,” does not clearly
    
    disclaim systems lacking these benefits.
    
           An examination of the prosecution history similarly reveals no statements that
    
    unequivocally narrow the claims to require independent manipulation.           Initially, the
    
    examiner rejected several claims as obvious, explaining that “[s]torage is always
    
    distinct, even if at distinct addresses.” In response, i4i stated:
    
           [T]he architecture of a document can be treated as a separate entity from
           the content of the document. Thus, the architecture of the document can
           be treated as an entity having distinct storage from the content of the
           document. This separation allows distinct processes to operate on the
           content and the architecture, with or without knowledge of the other. In
           other words, using the present invention, one could change the
    
    
    
    2009-1504                                    11
            architecture, (layout, structure, or presentation formation) of a document
            without even having access to the actual content of the document. This is
            achieved by extracting the metacodes from an existing document and
            creating a map of the location of the metacodes in the document and then
            storing the map and the content of the document separately.
    
    The reason for the examiner’s rejection helps us understand i4i’s response. In context,
    
    i4i’s response is best read as clarifying why the invention’s “storage means” are more
    
    than just “distinct addresses.” i4i’s subsequent discussion of the benefits of separate
    
    storage is not sufficiently “clear and unmistakable” to disavow embodiments lacking
    
    independent manipulation. Purdue Pharma, 438 F.3d at 1136.
    
            In light of the specification’s permissive language, the prosecution history, and
    
    the claim language, we conclude that “independent manipulation” is a benefit of
    
    separate storage, but not itself a limitation.
    
                                             III. Validity
    
            Microsoft also appeals two issues regarding the validity of i4i’s patent. The first
    
    is whether the invention would have been obvious to one of skill in the art. The second
    
    is whether Microsoft is entitled to JMOL or a new trial on validity, due to anticipation by
    
    a software program called S4.
    
            At trial, Microsoft argued that the ’449 patent was invalid based on several pieces
    
    of prior art. As relevant here, Microsoft argued that i4i’s invention would have been
    
    obvious in light of U.S. Patent No. 5,587,902 (“Kugimiya”), when combined with either
    
    an SGML editor known as Rita or U.S. Patent No. 6,101,512 (“DeRose”).                In the
    
    alternative, Microsoft argued that i4i’s invention was anticipated under 35 U.S.C.
    
    § 102(b) by the sale of a software program, SEMI-S4 (“S4”), by i4i before the critical
    
    date.
    
    
    
    
    2009-1504                                        12
           i4i disputed that it would have been obvious to combine Kugimiya with Rita or
    
    DeRose.      i4i presented evidence that Kugimiya was in a different field (language
    
    translation) than Rita, DeRose, or the ’449 patent, which address document editing. i4i
    
    also presented evidence of secondary considerations, including long-felt need, failure of
    
    others, and commercial success. As to anticipation, i4i also argued that S4 did not
    
    practice the ’449 patent because it did not create a “metacode map.”
    
           Before the case was submitted to the jury, Microsoft moved for JMOL on
    
    invalidity, arguing that i4i’s sale of S4 violated the on-sale bar under § 102(b). Microsoft
    
    did not move for pre-verdict JMOL on obviousness or with regard to other prior art. The
    
    verdict form did not require the jury to make separate findings for the different pieces of
    
    prior art.   Instead, the form asked:    “Did Microsoft prove by clear and convincing
    
    evidence that any of the listed claims of the ’449 patent are invalid?” The jury was
    
    instructed to answer “yes” if it found a particular claim invalid, but otherwise answer
    
    “no.” The jury found all the asserted claims not invalid.
    
                                         A. Obviousness
    
           On appeal we must decide whether the ’449 patent would have been obvious in
    
    light of some combination of Rita or DeRose with Kugimiya.
    
           The Rita prior art is a software program that allows users to create and edit
    
    documents using SGML, a markup language like XML. Rita stores the SGML tags and
    
    document’s content in a “tree structure.” This tree stores the tags and content together.
    
    DeRose discloses a system for generating, analyzing, and navigating electronic
    
    documents containing a markup language, such as XML or SGML.                     To assist
    
    navigation, DeRose and Rita use “pointers,” which allow the user to move between
    
    
    
    
    2009-1504                                   13
    different branches of the tree structure. Kugimiya discloses a system for translating
    
    documents from English to Japanese. As part of the translation process, Kugimiya
    
    finds, removes, and stores any XML tags in a separate file.           The program then
    
    translates the document’s content from English to Japanese, after which it puts the XML
    
    tags into the translated document.      After the tags are replaced, the separate file
    
    containing the tags is discarded.
    
          Although obviousness is a question of law, it is based on factual underpinnings.
    
    As always, our review of the ultimate legal question, whether the claimed invention
    
    would have been obvious, is de novo. Duro-Last, Inc. v. Custom Seal, Inc., 
    321 F.3d 1098
    , 1108 (Fed. Cir. 2003). The extent to which we may review the jury’s implicit
    
    factual findings depends on whether a pre-verdict JMOL was filed on obviousness. Id.;
    
    see also Jurgens v. McKasy, 
    927 F.2d 1552
    , 1557-58 (Fed. Cir. 1991).
    
          In this case, Microsoft has waived its right to challenge the factual findings
    
    underlying the jury’s implicit obviousness verdict because it did not file a pre-verdict
    
    JMOL on obviousness for the Rita, DeRose and Kugimiya references. Fed. R. Civ. P.
    
    50(a), (b). As we explained in Duro-Last, a party must file a pre-verdict JMOL motion
    
    on all theories, and with respect to all prior art references, that it wishes to challenge
    
    with a post-verdict JMOL.     321 F.3d at 1107-08.      Microsoft’s pre-verdict JMOL on
    
    anticipation, based on S4, was insufficient to preserve its right to post-verdict JMOL on
    
    a different theory (obviousness), or on different prior art (Rita, DeRose, Kugimiya).
    
    Duro-Last, 321 F.3d at 1107-08.
    
          Accordingly, we do not consider whether the evidence presented at trial was
    
    legally sufficient to support the jury’s verdict.   Our review is limited to determining
    
    
    
    
    2009-1504                                   14
    whether the district court’s legal conclusion of nonobviousness was correct, based on
    
    the presumed factual findings. Id. at 1108-09; Kinetic Concepts, Inc. v. Blue Sky Med.
    
    Group, Inc., 
    554 F.3d 1010
    , 1020-21 (Fed. Cir. 2009). In conducting this review, we
    
    must presume the jury resolved underlying factual disputes in i4i’s favor because the
    
    jury made no explicit factual findings. Duro-Last, 321 F.3d at 1108. This presumption
    
    applies to disputes about (1) the scope and content of the prior art; (2) differences
    
    between the prior art and asserted claims; (3) the existence of motivation to modify prior
    
    art references; and (4) the level of ordinary skill in the pertinent art. Id. at 1109; see
    
    also Graham v. John Deere Co., 
    383 U.S. 1
    , 17 (1966); Kinetic Concepts, 554 F.3d at
    
    1019.
    
            Microsoft’s argument on appeal—that it would have been obvious to combine
    
    DeRose or Rita with Kugimiya—depends heavily on (1) the scope of the prior art, and
    
    (2) whether a person of ordinary skill would have been motivated to combine the
    
    references’ teachings. These are questions of fact. Kinetic Concepts, 554 F.3d at
    
    1020-21. Similarly, Microsoft’s argument that the prior art discloses all of the claim
    
    limitations boils down to questions of fact: whether the “tree structure” in Rita and
    
    DeRose is a “metacode map,” and whether a “pointer” is an “address of use.” See id.;
    
    Graham, 383 U.S. at 17. The jury found all of the asserted claims not invalid, meaning
    
    the jury must have believed that there were differences between the prior art and
    
    asserted claims, and that a person of ordinary skill would not have been motivated to
    
    combine the references. Cf. Kinetic Concepts, 554 F.3d at 1019-20; Duro-Last, 321
    
    F.3d at 1108-09. Because we must view the evidence in the light most favorable to the
    
    verdict, all of these questions must be resolved against Microsoft, and in favor of i4i.
    
    
    
    
    2009-1504                                  15
    Arsement v. Spinnaker Exploration Co., 
    400 F.3d 238
    , 249, 252-53 (5th Cir. 2005); see
    
    Jurgens, 927 F.2d at 1557-58. In light of the jury’s implicit factual findings, Microsoft
    
    has not established that the asserted claims would have been obvious.
    
                                         B. Anticipation
    
           For anticipation, the question is whether the district court erred in denying
    
    Microsoft’s motion for post-verdict JMOL on invalidity, or alternatively a new trial, based
    
    on the sale of S4 violating the on-sale bar. See 35 U.S.C. § 102(b).
    
           S4 was a software program developed for a client called SEMI by i4i’s corporate
    
    predecessor. i4i’s founder, Michel Vulpe, hired Stephen Owens to help develop S4,
    
    which they delivered to SEMI in early 1993. S4 allowed the user to add and edit SGML
    
    tags in electronic documents. For storage purposes, S4 divided the document into
    
    “entities.” According to Vulpe and Owens, these entities were simply chunks of the
    
    SGML document, where the SGML tags were intermixed with the content. Both Vulpe
    
    and Owens testified that S4 did not create a “metacode map.”
    
           At trial, Microsoft argued that the sale of S4 before the critical date violated the
    
    on-sale bar. To prove invalidity by the on-sale bar, a challenger must show by clear and
    
    convincing evidence that the claimed invention was “on sale in this country, more than
    
    one year prior to the date of the application for patent in the United States.” Id.; Adenta
    
    GmbH v. OrthoArm, Inc., 
    501 F.3d 1364
    , 1371 (Fed. Cir. 2007). It is uncontested that
    
    S4 was sold in the United States before the critical date. At trial, the dispute was
    
    whether S4 practiced the “metacode map” limitation of the ’449 patent.
    
           Because the S4 source code was destroyed after the project with SEMI was
    
    completed (years before this litigation began), the dispute turned largely on the
    
    
    
    
    2009-1504                                   16
    credibility of S4’s creators, Vulpe and Owens, who are also the named inventors on the
    
    ’449 patent. Both testified that the S4 software sold to SEMI did not practice the ’449
    
    patent, for which they claimed the key innovation—the metacode map—was not even
    
    conceived until after the critical date. Both were extensively cross-examined. Vulpe
    
    was impeached with statements from a letter he had written to investors, as well as a
    
    funding application submitted to the Canadian government.
    
           On appeal, Microsoft argues that it was entitled to JMOL because it established a
    
    prima facie case of anticipation, which i4i could not rebut by relying on the inventors’
    
    testimony alone, absent corroboration. Alternatively, Microsoft contends the evidence
    
    was not sufficient to support the jury’s verdict of validity.
    
                                         1. Burden of Proof
    
           Microsoft’s contention regarding a prima facie case and i4i’s “rebuttal”
    
    misunderstands the nature of an anticipation claim under 35 U.S.C. § 102(b).
    
    Anticipation is an affirmative defense. See, e.g., Electro Med. Sys., S.A. v. Cooper Life
    
    Scis., Inc., 
    34 F.3d 1048
    , 1052 (Fed. Cir. 1994). We do not agree that i4i was required
    
    to come forward with corroboration to “rebut” Microsoft’s prima facie case of
    
    anticipation.   Corroboration is required in certain circumstances.   See, e.g., Martek
    
    Biosciences Corp. v. Nutrinova, Inc., 
    579 F.3d 1363
    , 1374-76 (Fed. Cir. 2009)
    
    (“Because Lonza sought to introduce the testimony of an alleged prior inventor under
    
    § 102(g) for the purpose of invalidating a patent, Lonza was required to produce
    
    evidence corroborating Dr. Long's testimony.”); Procter & Gamble Co. v. Teva Pharms.
    
    USA, Inc., 
    566 F.3d 989
    , 989-99 (Fed. Cir. 2009) (requiring corroboration where
    
    patentee tried to prove that the conception date was earlier than the filing date of a
    
    
    
    
    2009-1504                                     17
    potentially anticipatory patent); Henkel Corp. v. Procter & Gamble Co., 
    560 F.3d 1286
    
    (Fed. Cir. 2009) (interference); Symantec Corp. v. Computer Assocs. Int’l, Inc., 
    522 F.3d 1279
    , 1295-96 (Fed. Cir. 2008) (“An alleged co-inventor's testimony, standing alone,
    
    cannot rise to the level of clear and convincing evidence; he must supply evidence to
    
    corroborate his testimony.”). However, this is not a case where witness testimony was
    
    being used to overcome prior art by establishing an earlier date of invention.
    
           To support its argument that S4 practiced the ’449 patent, Microsoft offered
    
    testimony by a former i4i employee and its expert.         i4i responded with evidence,
    
    specifically testimony by S4’s inventors, that S4 did not practice the claimed method.
    
    Though we require corroboration of “any witness whose testimony alone is asserted to
    
    invalidate a patent,” Finnigan Corp. v. Int’l Trade Comm’n, 
    180 F.3d 1354
    , 1369-70
    
    (Fed. Cir. 1999) (emphasis added), here the inventor testimony was offered by i4i in
    
    response to Microsoft’s attack on the validity of the ’449 patent. It was not offered to
    
    meet Microsoft’s burden of proving invalidity by clear and convincing evidence. Cf.
    
    TypeRight Keyboard Corp. v. Microsoft Corp., 
    374 F.3d 1151
    , 1159-60 (Fed. Cir. 2004);
    
    Tex. Digital Sys., Inc. v. Telegenix, Inc., 
    308 F.3d 1193
    , 1217 (Fed. Cir. 2002); Finnigan,
    
    180 F.3d at 1367. We know of no corroboration requirement for inventor testimony
    
    asserted to defend against a finding of invalidity by pointing to deficiencies in the prior
    
    art. Accordingly, we hold that corroboration was not required in this instance, where the
    
    testimony was offered in response to a claim of anticipation and pertained to whether
    
    the prior art practiced the claimed invention.
    
    
    
    
    2009-1504                                   18
                                  2. Sufficiency of the Evidence
    
           In contrast to obviousness, Microsoft did move for pre-verdict JMOL regarding
    
    anticipation based on S4. We nonetheless conclude that there was sufficient evidence
    
    for a reasonable jury to find that the ’449 patent was not anticipated by the sale of S4.
    
    See Bellows v. Amoco Oil Co., 
    118 F.3d 268
    , 273 (5th Cir. 1997). At trial, the jury heard
    
    conflicting testimony on whether S4 met the “metacode map” limitation. In evaluating
    
    the evidence, the jury was free to disbelieve Microsoft’s expert, who relied on the S4
    
    user manual, and credit i4i’s expert, who opined that it was impossible to know whether
    
    the claim limitation was met without looking at S4’s source code. Although the absence
    
    of the source code is not Microsoft’s fault, the burden was still on Microsoft to show by
    
    clear and convincing evidence that S4 embodied all of the claim limitations. The jury’s
    
    finding of validity was supported by the testimony of the inventors (Vulpe and Owens),
    
    as well as their faxes to an attorney regarding the patent application.
    
                                       3. Jury Instructions
    
           Microsoft also challenges the jury instructions on its burden of proving
    
    anticipation. According to Microsoft, the burden of proof should have been less for prior
    
    art that was not before the PTO, as was the case for Rita and DeRose.
    
           We conclude that the jury instructions were correct in light of this court’s
    
    precedent, which requires the challenger to prove invalidity by clear and convincing
    
    evidence. See, e.g., Zenith Elecs. Corp. v. PDI Commc’n Sys., Inc., 
    522 F.3d 1348
    ,
    
    1363-64 (Fed. Cir. 2008).      This court’s decisions in Lucent Technologies, Inc. v.
    
    Gateway, Inc., 
    580 F.3d 1301
    , 1311-16 (Fed. Cir. 2009), and Technology Licensing
    
    Corp. v. Videotek, Inc., 
    545 F.3d 1316
    , 1327 (Fed. Cir. 2008), make clear that the
    
    
    
    
    2009-1504                                   19
    Supreme Court’s decision in KSR International Co. v. Teleflex Inc., 
    550 U.S. 398
    , 426
    
    (2007) did not change the burden of proving invalidity by clear and convincing evidence.
    
    Thus, based on our precedent, we cannot discern any error in the jury instructions.
    
                                           IV. Infringement
    
             Taking Microsoft’s arguments with regard to infringement in turn, we first review
    
    the jury instructions on infringement. We then decide whether the verdict is supported
    
    by substantial evidence.
    
                                         A. Jury Instructions
    
             At trial, i4i presented three theories of liability: direct, contributory, and induced
    
    infringement. Over Microsoft’s objection, the district court used a general verdict form,
    
    which did not require separate findings on the different theories. Instead, the form
    
    asked:     “Did i4i prove by a preponderance of the evidence that Microsoft infringes
    
    Claims 14, 18, or 20 of the ’449 patent?” The form then instructed the jury to answer
    
    “yes” or “no” for each claim. The jury answered “yes” for all asserted claims.
    
             On appeal, Microsoft argues that it is entitled to a new trial because of two
    
    alleged errors in the jury instructions regarding contributory infringement.             First,
    
    Microsoft argues it was error to use the term “component” rather than “material or
    
    apparatus.” In relevant part, the instructions provided:
    
             If you find someone has directly infringed the ’449 patent, then
             contributory infringement exists if i4i establishes by a preponderance of
             evidence that:
    
             1) Microsoft sold, offered for sale, or imported;
             2) A material component for use in practicing the patented claim—or
                patented method that is not a staple article of commerce suitable for
                substantial non-infringing use;
             3) With knowledge that the component was especially made or adapted
                for use in an infringing manner.
    
    
    
    2009-1504                                      20
    The corresponding statutory section, 35 U.S.C. § 271(c), uses the words “material or
    
    apparatus,” not “component,” for patented processes.         Although the district court’s
    
    instructions differed from the statute, this is not a case where the difference mattered.
    
    See Baker, 536 F.3d at 363-64 (reversing a jury verdict “only if the charge as a whole
    
    creates a substantial doubt as to whether the jury has been properly guided in its
    
    deliberations”). The parties’ infringement arguments did not turn on whether Word’s
    
    custom XML editor was a “component,” versus a “material or apparatus.” Nor is there
    
    any reason to think the jury was aware of the difference, or would have viewed the
    
    difference as anything but semantics had it known, because both parties used the terms
    
    interchangeably at trial. Under these circumstances, we are satisfied that the instruction
    
    properly guided the jury in its deliberations.
    
           Microsoft also argues that the district court erred by instructing the jury to focus
    
    on the custom XML editor, rather than all of Word, when deciding whether any
    
    noninfringing uses were “substantial.” Given the evidence presented at trial, the district
    
    court did not abuse its discretion. As we explained in Lucent, a particular tool within a
    
    larger software package may be the relevant “material or apparatus” when that tool is a
    
    separate and distinct feature. 580 F.3d at 1320-21. In Lucent, the infringement inquiry
    
    accordingly focused on the date-picker, even though that tool was included in Microsoft
    
    Outlook, a larger software package. Id. Although the software differs, our reasoning in
    
    Lucent applies equally here. At trial, i4i showed that some versions of Word 2003
    
    included the custom XML editor, while others did not. Dr. Rhyne opined that this ability
    
    to “leave [the editor] out or put it in” various Word products showed that the editor was a
    
    separate and distinct feature. Thus, there was sufficient evidence before the jury for it
    
    
    
    
    2009-1504                                    21
    to conclude that the relevant “material or apparatus” was the custom XML editor, not all
    
    of Word. Accordingly, the jury was properly instructed that it should focus on the editor,
    
    not all of Word. See Ricoh Co. v. Quanta Computer Inc., 
    550 F.3d 1325
    , 1337 (Fed.
    
    Cir. 2008).
    
                                  B. Sufficiency of the Evidence
    
           Microsoft also challenges the sufficiency of evidence supporting the jury’s
    
    general verdict of infringement.       Infringement is a question of fact.         Because
    
    infringement was tried to a jury, we review the verdict only for substantial evidence.
    
    ACCO Brands, Inc. v. ABA Locks Mfrs. Co., 
    501 F.3d 1307
    , 1311 (Fed. Cir. 2007).
    
           Before we consider the evidence, we pause briefly to address what errors are
    
    fatal to a general verdict. Different rules apply depending upon whether the flaw is in
    
    the legal theory or the evidence. We must set aside a general verdict if the jury was told
    
    it could rely on any of two or more independent legal theories, one of which was
    
    defective. Walther, 952 F.2d at 126; see Northpoint Tech., Ltd. v. MDS Am., Inc., 
    413 F.3d 1301
    , 1311-12 (Fed. Cir. 2005). However, we will not set aside a general verdict
    
    “simply because the jury might have decided on a ground that was supported by
    
    insufficient evidence.” Walther, 952 F.2d at 126 (emphasis added). We will uphold
    
    such a verdict if there was sufficient evidence to support any of the plaintiff’s alternative
    
    factual theories; we assume the jury considered all the evidence and relied upon a
    
    factual theory for which the burden of proof was satisfied. See Northpoint Tech., 413
    
    F.3d at 1311-12.
    
           In this case, Microsoft argues that the general verdict must be set aside unless
    
    both of i4i’s alternative legal theories, contributory infringement and induced
    
    
    
    
    2009-1504                                    22
    infringement, are supported by substantial evidence. We disagree: the verdict must be
    
    upheld if substantial evidence supports either legal theory. Microsoft’s argument fails to
    
    distinguish between defects in legal theories and defects in the factual evidence. In this
    
    case, the jury was instructed that it could rely on any of three legal theories—direct,
    
    contributory, or induced infringement. All of these theories are legally valid and the
    
    corresponding instructions on each were proper. Because the jury could not have relied
    
    on a legally defective theory, the only remaining question is whether there was sufficient
    
    evidence to support either of i4i’s independently sufficient legal theories, contributory
    
    infringement or induced infringement. 1 We conclude that there was.
    
                                     1. Direct Infringement
    
          To succeed on a theory of contributory or induced infringement, i4i was required
    
    to show direct infringement of the ’449 patent. Lucent, 580 F.3d at 1317; see also
    
    Glenayre Elecs., Inc. v. Jackson, 
    443 F.3d 851
    , 858 (Fed. Cir. 2006). Because the
    
    claims asserted by i4i are method claims, Microsoft’s sale of Word, without more, did
    
    not infringe the ’449 patent. Lucent, 580 F.3d at 1317. Direct infringement occurs only
    
    when someone performs the claimed method. Id.
    
          Based on the evidence presented at trial, a reasonable jury could have found that
    
    at least one person performed the methods claimed in the ’449 patent. This evidence
    
    included testimony by i4i’s expert (Dr. Rhyne), a joint stipulation, and Microsoft’s
    
    response to interrogatories. Rhyne opined that Word’s custom XML editor met all of the
    
    
    
          1
                   Even though we could affirm the jury’s verdict of infringement so long as
    there was sufficient evidence of direct infringement by Microsoft, here we focus on
    indirect infringement because that was the basis for i4i’s damages estimate, which the
    jury apparently credited. See Lucent, 580 F.3d at 1334-35; Dynacore Holdings Corp. v.
    U.S. Philips Corp., 
    363 F.3d 1263
    , 1274 (Fed. Cir. 2004).
    
    
    2009-1504                                  23
    limitations of the asserted claims because the editor separated a document into a “CP
    
    stream” of content and a separate data structure containing the metacodes and their
    
    addresses of use. Rhyne testified that this separate data structure met the “metacode
    
    map” limitation. Though Microsoft’s expert offered conflicting evidence, opining that
    
    Word did not infringe the asserted claims, the jury was free to disbelieve Microsoft’s
    
    expert and credit i4i’s expert, who testified that the ’449 patent was infringed if Word
    
    was used to open an XML document, edit an XML document, or save a document
    
    containing custom XML in an XML file format. The joint stipulation and Microsoft’s
    
    interrogatory responses unequivocally state that Word was used in these ways. Cf.
    
    Fresenius USA, Inc. v. Baxter Int’l, Inc., 
    582 F.3d 1288
    , 1298-99 (Fed. Cir. 2009);
    
    Martek, 579 F.3d at 1371-72.
    
                                   2. Contributory Infringement
    
          For contributory infringement, the question is whether there is substantial
    
    evidence to support a finding under this theory.      A party is liable for contributory
    
    infringement if that party sells, or offers to sell, a material or apparatus for use in
    
    practicing a patented process. That “material or apparatus” must be a material part of
    
    the invention, have no substantial noninfringing uses, and be known (by the party) “to
    
    be especially made or especially adapted for use in an infringement of such patent.” 35
    
    U.S.C. § 271(c); Cross Med. Prods., Inc. v. Medtronic Sofamor Danek, Inc., 
    424 F.3d 1293
    , 1312 (Fed. Cir. 2005).
    
          Based on the evidence presented at trial, the jury could have reasonably
    
    concluded that the custom XML editor had no substantial, noninfringing uses and that
    
    Microsoft knew that the use of the custom XML editor would infringe i4i’s patent. At
    
    
    
    
    2009-1504                                  24
    trial, Rhyne agreed that the custom XML editor could be used in three noninfringing
    
    ways, but opined that none were “substantial.”       Rhyne explained that saving a
    
    document in the noninfringing, binary format deprived users of the very benefit XML was
    
    intended to provide:    namely, allowing another program to search and read the
    
    document’s metacode tags.
    
          Despite Microsoft’s contention to the contrary, evidence that some users saved
    
    XML documents in these noninfringing formats does not render the jury’s verdict
    
    unreasonable. Whether a use is “substantial,” rather than just “unusual, far-fetched,
    
    illusory, impractical, occasional, aberrant, or experimental,” cannot be evaluated in a
    
    vacuum. Vita-Mix Corp. v. Basic Holding, Inc., 
    581 F.3d 1317
    , 1327 (Fed. Cir. 2009).
    
    In assessing whether an asserted noninfringing use was “substantial,” the jury was
    
    allowed to consider not only the use’s frequency, but also the use’s practicality, the
    
    invention’s intended purpose, and the intended market. See id. Here, the jury heard
    
    ample testimony that the noninfringing, binary file format was not a practical or
    
    worthwhile use for the XML community, for which the custom XML editor was designed
    
    and marketed.
    
          Further, the jury could have reasonably concluded that Microsoft knew that use
    
    of the editor would infringe the ’449 patent, based on the circumstantial evidence
    
    presented at trial. Cf. Lucent, 580 F.3d at 1318, 1321-22; Fuji Photo Film Co. v. Jazz
    
    Photo Corp., 
    394 F.3d 1368
    , 1377-78 (Fed. Cir. 2005). Here, the evidence showed that
    
    the Word development team heard a presentation by i4i about software practicing the
    
    ’449 patent, asked how the software worked, and received marketing materials on the
    
    software. Internal Microsoft emails showed that other Microsoft employees received a
    
    
    
    
    2009-1504                                 25
    marketing email from i4i containing the patent number, were “familiar” with i4i’s
    
    products, and believed the Word’s custom XML editor would render that product
    
    “obsolete.” Based on this evidence, the jury could have reasonably concluded that
    
    Microsoft knew about the ’449 patent and knew use of its custom XML editor would
    
    infringe.
    
                                    3. Induced Infringement
    
           Though we need not reach this theory because substantial evidence supports
    
    i4i’s theory of contributory infringement, we do so for the sake of completeness. On
    
    appeal, the sole question is whether there is substantial evidence to support a verdict of
    
    induced infringement.      To prove inducement, the patentee must show direct
    
    infringement, and that the alleged infringer “knowingly induced infringement and
    
    possessed specific intent to encourage another’s infringement.” MEMC Elec. Materials,
    
    Inc. v. Mitsubishi Materials Silicon Corp., 
    420 F.3d 1369
    , 1378 (Fed. Cir. 2005); see 35
    
    U.S.C. § 271(b).
    
           Based on the evidence presented at trial, a reasonable jury could have
    
    concluded that Microsoft had the “affirmative intent to cause direct infringement.” DSU
    
    Med. Corp v. JMS Co., 
    471 F.3d 1293
    , 1306 (Fed. Cir. 2006) (en banc in relevant part).
    
    The jury saw and heard about Microsoft’s online training and user support resources,
    
    which provided detailed instructions on using Word’s custom XML editor. i4i’s expert
    
    opined that using the editor as directed by these materials would infringe the ’449
    
    patent.     The instructional materials were thus substantial evidence that Microsoft
    
    intended the product to be used in an infringing manner. See DSU, 471 F.3d at 1303,
    
    1305. Unlike the instructions in Vita-Mix, 581 F.3d at 1328-29, which taught a use the
    
    
    
    
    2009-1504                                  26
    defendant “could have reasonably believed was non-infringing” and another use that
    
    was “non-infringing,” here there was substantial evidence Microsoft knew its instructions
    
    would result in infringing use.      As explained in our discussion of contributory
    
    infringement, Microsoft’s internal emails are substantial evidence of Microsoft’s
    
    knowledge, both of the ’449 patent and the infringing nature of Word’s custom XML
    
    editor. Regarding i4i’s software that practiced the invention, one Microsoft employee
    
    remarked: “[W]e saw this tool some time ago and met its creators. Word [2003] will
    
    make it obsolete. It looks great for XP though.” Evidence that consumers were using
    
    Word in an infringing manner included Microsoft data on usage of Word, as well as a
    
    Microsoft marketing document listing “real” examples of custom XML’s use in Word.
    
                                          V. Damages
    
          Microsoft protests the $200 million damages award on several grounds. We
    
    begin by reviewing the propriety of various evidentiary rulings. We then decide whether
    
    the district court abused its discretion by denying Microsoft a new trial on damages.
    
                                     A. Evidentiary Rulings
    
          We review evidentiary rulings for abuse of discretion. Huss v. Gayden, 
    571 F.3d 442
    , 452 (5th Cir. 2009); see Paz v. Brush Engineered Materials, Inc., 
    555 F.3d 383
    ,
    
    387-88 (5th Cir. 2009).    Microsoft challenges the admission of expert testimony on
    
    damages, as well as a survey relied on by the expert. We address each in turn.
    
                                      1. Expert Testimony
    
          To determine whether expert testimony was properly admitted under Rule 702 of
    
    the Federal Rules of Evidence, we use the framework set out in Daubert v. Merrell Dow
    
    
    
    
    2009-1504                                  27
    Pharmaceuticals, Inc., 
    509 U.S. 579
    , 589-90 (1993). 2 Daubert requires the district court
    
    ensure that any scientific testimony “is not only relevant, but reliable.” Id. at 589; see
    
    also Kumho Tire Co. v. Carmichael, 
    526 U.S. 137
    , 141-42 (1999).                When the
    
    methodology is sound, and the evidence relied upon sufficiently related to the case at
    
    hand, disputes about the degree of relevance or accuracy (above this minimum
    
    threshold) may go to the testimony’s weight, but not its admissibility. Knight v. Kirby
    
    Inland Marine Inc., 
    482 F.3d 347
    , 351 (5th Cir. 2007); Moore v. Ashland Chem. Inc., 
    151 F.3d 269
    , 276 (5th Cir. 1998) (en banc).
    
           On appeal, Microsoft challenges the expert testimony by Dr. Wagner, i4i’s
    
    damages expert. Wagner opined that a reasonable damages award would be $200
    
    million dollars, based on a hypothetical negotiation between i4i and Microsoft at the time
    
    the infringement began. To come up with the $200 million figure, Wagner calculated a
    
    royalty rate ($98), then multiplied that rate by the number of Word products actually
    
    used in an infringing manner (2.1 million).
    
           At trial, the parties hotly disputed the correctness of the $98 royalty rate.
    
    Microsoft argued that this rate was exorbitant given the price of certain Word products,
    
    which could be as little as $97. As further evidence of its unreasonableness, Microsoft
    
    pointed out that the rate resulted in a total damages amount ($200 million) greatly
    
    exceeding the $1-$5 million Microsoft had paid to license other patents. In response, i4i
    
    had its expert (Wagner) give a detailed explanation for how he arrived at the $98 royalty
    
    
    
           2
                   An expert witness with “scientific, technical, or otherwise specialized
    knowledge,” may testify and form an opinion “if (1) the testimony is based upon
    sufficient facts or data, (2) the testimony is the product of reliable principles and
    methods; and (3) the witness has applied the principles and methods reliably to the
    facts of the case.” Fed. R. Evid. 702.
    
    
    2009-1504                                     28
    rate. Wagner testified that he first chose an appropriate “benchmark” in order to value
    
    Microsoft’s use of the claimed invention at the time of the hypothetical negotiation.
    
    Wagner chose a product called XMetaL as his benchmark, which had a retail price of
    
    $499. To calculate the licensing fee, Wagner multiplied the price of XMetaL ($499) by
    
    Microsoft’s profit margin (76.6%), based on his assumption that any licensing fee would
    
    be a fraction of the profits. Wagner then applied the 25-percent rule to this number,
    
    which assumes the inventor will keep 25% of the profits from any infringing sales. This
    
    resulted in a baseline royalty rate of $96. Wagner testified that the 25-percent rule was
    
    “well-recognized” and “widely used” by people in his field.
    
           To support his royalty calculation, Wagner adjusted the baseline royalty rate of
    
    ($96) using the factors set out in Georgia-Pacific Corp. v. U.S. Plywood Corp., 318 F.
    
    Supp. 1116, 1120 (S.D.N.Y. 1970). 3 Based on the Georgia-Pacific factors, Wagner
    
    then increased the baseline from $96 to $98, which was the “reasonable royalty rate” he
    
    
    
           3
                  These factors include: (1) royalties the patentee has received for licensing
    the patent to others; (2) rates paid by the licensee for the use of comparable patents; (3)
    the nature and scope of the license (exclusive or nonexclusive, restricted or non-
    restricted by territory or product type); (4) any established policies or marketing
    programs by the licensor to maintain its patent monopoly by not licensing others to use
    the invention or granting licenses under special conditions to maintain the monopoly; (5)
    the commercial relationship between the licensor and licensee, such as whether they
    are competitors; (6) the effect of selling the patented specialty in promoting sales of
    other products of the licensee; (7) the duration of the patent and license term; (8) the
    established profitability of the product made under the patent, including its commercial
    success and current popularity; (9) the utility and advantages of the patent property over
    old modes or devices; (10) the nature of the patented invention and the benefits to
    those who have used the invention; (11) the extent to which the infringer has used the
    invention and the value of that use; (12) the portion of profit or of the selling price that
    may be customary in that particular business to allow for use of the invention or
    analogous inventions; (13) the portion of the realizable profit that should be credited to
    the invention as opposed to its non-patented elements; (14) the opinion testimony of
    qualified experts; and (15) the results of a hypothetical negotiation between the licensor
    and licensee. Id.
    
    
    2009-1504                                   29
    used in calculating the $200-$207 million damages estimate.             Specifically, Wagner
    
    concluded that factors 3, 5, 6, 9, and 11 affected the baseline rate.
    
           Wagner opined that factor 3, which considers the license’s terms, lowered the
    
    royalty rate because his hypothetical license did not give Microsoft know-how, additional
    
    cooperation or trade secrets, just non-exclusive use in the United States. However,
    
    Wagner opined that factors 5, 6, 9, and 11 increased the royalty rate. For factor 5,
    
    which looks at the commercial relationship between the licensor and licensee, Wagner
    
    found that Microsoft was a direct competitor of i4i, which meant any license would
    
    destroy a “very large segment” of i4i’s market. For factor 6, which asks whether the
    
    patented technology promotes the sale of other products, Wagner concluded that the
    
    infringing custom XML editor was critical to Microsoft’s sales generally, as evidenced by
    
    internal Microsoft statements that a custom XML editor was “one of the most important
    
    ways” for encouraging users to purchase new Word products.              Examining factor 9,
    
    which examines the infringer’s need for taking a license, Wagner opined that Microsoft
    
    had no commercially acceptable, non-infringing alternatives to using i4i’s patent. This
    
    opinion was based on internal Microsoft documents describing Microsoft’s interest in
    
    creating such a custom XML editor, and prolonged inability to do so. For factor 11,
    
    which looks at the use and value of the patented technology to Microsoft, Wagner
    
    concluded that the custom XML editor was a critical addition to Word. In support of this
    
    view, i4i presented statements by Microsoft employees that custom XML was not a
    
    “slight addition [but i]t’s more like 90 percent of the value,” was “where the future is,
    
    seriously,” and “the glue that holds the Office ecosystem together.” Based on all of
    
    
    
    
    2009-1504                                   30
    these Georgia-Pacific factors, Wagner increased the baseline royalty rate by $2, for a
    
    total of $98.
    
           On appeal, Microsoft ably points out various weaknesses in the damage
    
    calculations by i4i’s expert. At their heart, however, Microsoft’s disagreements are with
    
    Wagner’s conclusions, not his methodology. Daubert and Rule 702 are safeguards
    
    against unreliable or irrelevant opinions, not guarantees of correctness.          We have
    
    consistently upheld experts’ use of a hypothetical negotiation and Georgia-Pacific
    
    factors for estimating a reasonable royalty. See, e.g., Micro Chem., Inc. v. Lextron, Inc.,
    
    
    317 F.3d 1387
    , 1393 (Fed. Cir. 2003); Interactive Pictures Corp. v. Infinite Pictures, Inc.,
    
    
    274 F.3d 1371
    , 1384 (Fed. Cir. 2001). Wagner’s testimony about the acceptance of the
    
    hypothetical negotiation model among damage experts and economists, combined with
    
    his methodical explication of how he applied the model to the relevant facts, satisfied
    
    Rule 702 and Daubert. See Daubert, 509 U.S. at 593. Given Wagner’s testimony
    
    about his credentials, the district court did not abuse its discretion in finding Wagner
    
    qualified to apply the methodology. See Pipitone v. Biomatrix, Inc., 
    288 F.3d 239
    , 249-
    
    50 (5th Cir. 2002). Microsoft’s quarrel with the facts Wagner used go to the weight, not
    
    admissibility, of his opinion.
    
           We further hold that Wagner’s opinion was “based on sufficient facts or data.”
    
    Fed. R. Evid. 702. At trial, Microsoft disputed which facts were relevant for determining
    
    a reasonable royalty rate. In particular, Microsoft focused on the benchmark (XMetaL),
    
    the resulting baseline royalty rate, and i4i’s survey for estimating infringing use.
    
           Regarding the benchmark, Wagner explained that he chose XMetaL because it
    
    was the product Microsoft bought and used before developing its own custom XML
    
    
    
    
    2009-1504                                    31
    editor, it was the cheapest of the custom XML editors available on the market at the
    
    time, and it was one of three principal competitors Microsoft identified in the custom
    
    XML market. Microsoft contended that a better estimate of the custom XML editor’s
    
    value was $50, the difference in price between versions of Word with and without the
    
    editor. Microsoft also argued that because XMetaL has many additional features
    
    besides custom XML editing, the $499 retail price overestimated the value of the
    
    custom XML editor. In response, Wagner acknowledged that not all users of custom
    
    XML would have switched to a high-end product like XMetaL, but that those “who really
    
    needed that functionality” would have, requiring them to buy one of the commercially
    
    available products, even if it had many superfluous features. Wagner clarified that his
    
    damages estimate only considered users who “really needed” the custom XML editor,
    
    making it inappropriate to use the $50 price difference paid by all purchasers of Word,
    
    regardless of whether they infringed or not.
    
           As for using the baseline royalty rate ($96) as the starting point for the Georgia-
    
    Pacific analysis, Wagner opined that it was necessary because of Microsoft’s business
    
    strategy.   According to Wagner, Microsoft’s primary goal is to make sales, not to
    
    maximize the price it charges for each additional feature. In making sales, Wagner
    
    explained that Microsoft’s biggest competitor is always itself: Microsoft has to convince
    
    consumers to purchase new versions of its products, even if they already have a
    
    “perfectly good” copy of an older version. To incentivize users to upgrade, Wagner
    
    testified that Microsoft included new features at no additional cost, making it difficult to
    
    value the new features.
    
    
    
    
    2009-1504                                   32
           As for the survey, i4i’s survey expert (Dr. Wecker) explained that it was limited to
    
    estimating infringing use by businesses; i4i did not even seek damages for infringing
    
    use by individual consumers.        Wecker sent the survey to 988 large and small
    
    businesses randomly selected from a database of 13 million U.S. companies. Wecker
    
    explained that this large sample size was necessary to ensure he received sufficient
    
    responses (between 25 and 100) because many companies are “too busy” or have
    
    policies against responding to surveys.         The survey consisted of screening and
    
    substantive questions. The screening questions helped identify the proper person to
    
    speak with about the company’s use of custom XML. Wecker received 46 responses to
    
    the survey, which consisted of approximately 40 substantive questions. For all of the
    
    questions, the responder had the option of saying they did not know. Any company that
    
    took the survey received $35, regardless of the answers they gave. Wecker explained
    
    that he used logical imputation, an accepted procedure for statisticians to resolve
    
    inconsistent survey responses, to make some of the answers consistent. Of those that
    
    responded to the survey, 19 companies reported using Word in an infringing manner.
    
    Wecker assumed that all the companies that did not respond (942) did not use Word in
    
    an infringing manner.     Based on these assumptions, Wecker determined that 1.9%
    
    (19/988) of all copies of Word sold to businesses between 2003 and 2008 were used in
    
    an infringing manner. Wecker then multiplied this percentage (1.9%) by the number of
    
    copies of Word sold to businesses, for a total of 1.8 million infringing uses. 4
    
    
    
    
           4
                   Based on sales of Word, Wagner then estimated the number of additional
    infringing uses that occurred between the end of the survey date and start of trial, to
    give a total of 2.1 million.
    
    
    2009-1504                                    33
          Wecker opined that this estimate was conservative, “really an underestimate”
    
    and “way low” because he assumed every company that did not respond was not
    
    infringing, which was highly unlikely and introduced a “serious downward bias.”
    
    Microsoft contested the accuracy of the survey, based on the low response rate, use of
    
    logical imputation to correct inconsistent answers, and questions requiring estimates of
    
    Word usage going back several years.        In response, i4i’s experts opined that the
    
    survey’s conservative assumptions about the unresponsive companies mitigated (and
    
    perhaps even overcorrected) for those weaknesses.
    
          Microsoft is correct that i4i’s expert could have used other data in his
    
    calculations. The existence of other facts, however, does not mean that the facts used
    
    failed to meet the minimum standards of relevance or reliability. See Fed. R. Evid. 702
    
    advisory committee’s note. Under Rule 702, the question is whether the expert relied
    
    on facts sufficiently related to the disputed issue. Here, that issue was a reasonable
    
    royalty for the ’449 patent. We conclude that Wagner based his calculations on facts
    
    meeting these minimum standards of relevance and reliability. Fed. R. Evid. 702.
    
          As i4i’s expert explained, the facts were drawn from internal Microsoft
    
    documents, publicly available information about other custom XML editing software, and
    
    a survey designed to estimate the amount of infringing use. Thus, these facts had a
    
    sufficient nexus to the relevant market, the parties, and the alleged infringement. While
    
    the data were certainly imperfect, and more (or different) data might have resulted in a
    
    “better” or more “accurate” estimate in the absolute sense, it is not the district court’s
    
    role under Daubert to evaluate the correctness of facts underlying an expert’s
    
    testimony. See Micro Chem., 317 F.3d at 1392. Questions about what facts are most
    
    
    
    
    2009-1504                                  34
    relevant or reliable to calculating a reasonable royalty are for the jury. The jury was
    
    entitled to hear the expert testimony and decide for itself what to accept or reject. See
    
    Pipitone, 288 F.3d at 249-50.
    
            As the Supreme Court explained in Daubert, “[v]igorous cross-examination,
    
    presentation of contrary evidence, and careful instruction on the burden of proof are the
    
    traditional and appropriate means of attacking shaky but admissible evidence.” 509
    
    U.S. at 596.     Microsoft had these opportunities, and ably availed itself of them.
    
    Microsoft presented expert testimony and attacked the benchmark, survey, and
    
    calculation’s reasonableness on cross-examination.       Cf. Micro Chem., 317 F.3d at
    
    1392.
    
            Based on this record, the district court did not abuse its discretion in admitting
    
    Wagner’s expert testimony on damages.
    
                                          2. The Survey
    
            Microsoft also challenges the district court’s admission of the survey used to
    
    estimate the amount of infringing use. We do not agree with Microsoft that the danger
    
    of unfair prejudice substantially outweighed the survey’s probative value, so as to
    
    warrant exclusion under Rule 403. Both of i4i’s experts, Wagner and Wecker, opined
    
    that the survey dramatically underestimated the amount of infringing use. Given the
    
    survey’s conservative assumptions, the district court did not abuse its discretion in
    
    admitting the survey.     Further, the survey was properly admitted over Microsoft’s
    
    hearsay objection under Federal Rule of Evidence 703, since the survey was used to
    
    estimate the amount of infringing use, a key number in i4i’s damage calculation. Given
    
    the survey’s importance, evidence about its methodology and findings could certainly
    
    
    
    
    2009-1504                                   35
    help the jury evaluate the expert testimony.     See C. A. May Marine Supply Co. v.
    
    Brunswick Corp., 
    649 F.2d 1049
    , 1054-55 (5th Cir. 1981). The testimony of Wecker,
    
    the expert who helped design the survey, sufficed to show that the survey was compiled
    
    in accordance with acceptable survey methods.
    
          For these reasons, the district court did not abuse its discretion in admitting the
    
    survey.
    
                          B. Reasonableness of the Damages Award
    
          Microsoft urges us to follow this court’s recent decision in Lucent, 
    580 F.3d 1301
    ,
    
    and hold that $200 million is not a reasonable royalty. We cannot, however, because
    
    the procedural posture of this case differs from Lucent, and that difference controls this
    
    case. Although Microsoft now objects to the size of the damages award, we cannot
    
    reach that question because Microsoft did not file a pre-verdict JMOL on damages.
    
          In Lucent, the accused infringer filed a pre-verdict JMOL motion challenging the
    
    sufficiency of the damages’ evidence.      Id. at 1309.   Though Microsoft could have
    
    similarly filed a pre-verdict JMOL, for whatever reason, it chose not to. See Fed. R. Civ.
    
    P. 50(a). On appeal, what that strategic decision means for Microsoft is that we cannot
    
    decide whether there was a sufficient evidentiary basis for the jury’s damages award.
    
    Cf. Lucent, 580 F.3d at 1332 (holding that “we see little evidentiary basis under
    
    Georgia-Pacific” for the damages award).        Asking whether a damages award is
    
    “reasonable,” “grossly excessive or monstrous,” “based only on speculation or
    
    guesswork,” or “clearly not supported by the evidence,” are simply different ways of
    
    asking whether the jury’s award is supported by the evidence. Fuji Photo, 394 F.3d at
    
    1378; Catalina Lighting, Inc. v. Lamps Plus, Inc., 
    295 F.3d 1277
    , 1290 (Fed. Cir. 2002).
    
    
    
    
    2009-1504                                  36
    Microsoft waived its ability to have us decide that question by failing to file a pre-verdict
    
    JMOL on damages. Fed. R. Civ. P. 50(a), (b).
    
           Had Microsoft filed a pre-verdict JMOL, it is true that the outcome might have
    
    been different. Given the opportunity to review the sufficiency of the evidence, we could
    
    have considered whether the $200 million damages award was “grossly excessive or
    
    monstrous” in light of Word’s retail price and the licensing fees Microsoft paid for other
    
    patents. Cf. Lucent, 580 F.3d at 1325-32. As this court did in Lucent, we could have
    
    analyzed the evidentiary basis for the Georgia-Pacific factors, and whether the
    
    benchmark (XMetaL) was sufficiently comparable. Id.
    
           However, we cannot. Instead of the more searching review permitted under Rule
    
    50(b), we are constrained to review the verdict under the much narrower standard
    
    applied to denials of new trial motions. Duff, 489 F.3d at 730. This standard is highly
    
    deferential: we may set aside a damages award and remand for a new trial “only upon
    
    a clear showing of excessiveness.” Id. (emphasis added). To be excessive, the award
    
    must exceed the “maximum amount calculable from the evidence.” Carlton v. H. C.
    
    Price Co., 
    640 F.2d 573
    , 579 (5th Cir. 1981). We must affirm unless the appellant
    
    clearly shows there was no evidence to support the jury’s verdict. Duff, 489 F.3d at
    
    730, 732; see also Industrias Magromer, 293 F.3d at 923.
    
           Under this highly deferential standard, we cannot say that Microsoft is entitled to
    
    a new trial on damages.       The damages award, while high, was supported by the
    
    evidence presented at trial, including the expert testimony—which the jury apparently
    
    credited. See Unisplay, S.A. v. Am. Elec. Sign Co., 
    69 F.3d 512
    , 519 (Fed. Cir. 1995).
    
    On appeal, the question is not whether we would have awarded the same amount of
    
    
    
    
    2009-1504                                    37
    damages if we were the jury, but rather whether there is evidence to support what the
    
    jury decided. See Fuji Photo, 394 F.3d at 1378. Here, the jury’s award was supported
    
    by the testimony of Wagner, i4i’s damage expert, who opined that a reasonable royalty
    
    was between $200 and $207 million. The award was also supported by the testimony
    
    of Wecker, i4i’s survey expert, who explained that the survey’s conservative
    
    assumptions (i.e., that none of the companies who failed to respond infringed) meant
    
    the damages figure was “really an underestimate” and “way low.”              As we have
    
    recognized previously, any reasonable royalty analysis necessarily involves an element
    
    of approximation, and uncertainty. See Lucent, 580 F.3d at 1325; Unisplay, 69 F.3d at
    
    517. Given the intensely factual nature of a damages determination and our deferential
    
    standard of review, we are not in a position to second-guess or substitute our judgment
    
    for the jury’s.
    
                                     C. Enhanced Damages
    
           Microsoft has only appealed the district court’s decision to enhance damages
    
    under 35 U.S.C. § 284.
    
           Section 284 gives the district court discretion to “increase the damages up to
    
    three times the amount found or assessed” by the jury. A finding of willful infringement
    
    is a prerequisite to the award of enhanced damages. In re Seagate Technology, LLC.,
    
    
    497 F.3d 1360
    , 1368 (Fed. Cir. 2007) (en banc). In this case, the question of whether
    
    Microsoft willfully infringed the ’449 patent was submitted to the jury, which was
    
    instructed that i4i had to prove Microsoft (1) was aware of the ’449 patent; (2) acted
    
    despite an objectively high likelihood that its actions infringed a valid patent; where (3)
    
    this objectively high risk was either known or so obvious it should have been known to
    
    
    
    
    2009-1504                                   38
    Microsoft. The verdict form instructed the jury to answer “yes” or “no” to “Did i4i prove
    
    by clear and convincing evidence that Microsoft’s infringement was willful?” The jury
    
    answered “yes.” Based on the jury’s willfulness finding, i4i made a post-trial motion for
    
    enhanced damages.
    
           The district court then analyzed the factors set out in Read Corp. v. Portec, Inc.,
    
    
    970 F.2d 816
    , 826-27 (Fed. Cir. 1992), in deciding whether to enhance damages. The
    
    district court found that factors 2, 4, 6, 7, and 8 supported enhancement. Factors 1 and
    
    9, combined with i4i’s delay in bringing suit, were found to weigh against enhancement.
    
    For factor 1, which considers whether the infringer deliberately copied the ideas or
    
    design of another, the district court found no evidence that Microsoft deliberately copied
    
    any of i4i’s products. For factor 2, which considers whether the infringer knew of the
    
    patent, investigated the patent’s scope and formed a good-faith belief of its invalidity or
    
    noninfringement, the district court found Microsoft was aware of i4i’s patent, never
    
    formed a good faith belief of noninfringement, and clearly intended to add a custom
    
    XML editor in Word with similar capabilities to i4i’s patented products. For factor 4,
    
    which considers the infringer’s size and financial condition, the district court found that
    
    the jury’s award, while “substantial,” was only a small fraction of Microsoft’s profits from
    
    the sale of Word products.         The district court also noted that Microsoft was
    
    “undisputedly” the world leader in software for business and personal computing, with
    
    revenues of $60.42 billion in 2008 alone. As for factors 6, 7, and 8, the district court
    
    found that Microsoft had started using the infringing products more than five years ago
    
    (in 2002), failed to conduct an infringement analysis after being notified of the ’449
    
    patent again in 2003, and implemented the infringing custom XML editor with the
    
    
    
    
    2009-1504                                   39
    purpose of rendering i4i’s products obsolete. Although statutorily authorized to increase
    
    the award to $600 million, the district court awarded only $40 million in enhanced
    
    damages. See 35 U.S.C. § 284.
    
          On this record, we cannot conclude that the district court abused its discretion in
    
    weighing the evidence or applying the Read factors.        See Amsted Indus., Inc. v.
    
    Buckeye Steel Castings Co., 
    24 F.3d 178
    , 184 (Fed. Cir. 1994). The district court made
    
    detailed factual findings which, taken together, support its award of enhanced damages.
    
    See Jurgens v. CBK, Ltd., 
    80 F.3d 1566
    , 1570-71 (Fed. Cir. 1996). In deciding whether
    
    to enhance damages, the district court properly declined to reapply the test for
    
    willfulness set out in Seagate, 
    497 F.3d 1360
    . Although a finding of willfulness is a
    
    prerequisite for enhancing damages under § 284, the standard for deciding whether—
    
    and by how much—to enhance damages is set forth in Read, not Seagate. See 35
    
    U.S.C. § 284; SRI Int’l, Inc. v. Advanced Tech. Labs., Inc., 
    127 F.3d 1462
    , 1468-69
    
    (Fed. Cir. 1997); cf. Seagate, 497 F.3d at 1371. Here, the question of willfulness was
    
    submitted to the jury. Microsoft does not dispute that the jury instructions were proper
    
    under Seagate, 497 F.3d at 1371. The test for willfulness is distinct and separate from
    
    the factors guiding a district court’s discretion regarding enhanced damages. Compare
    
    id., with Read, 970 F.2d at 826-27. Under the Read factors, the district court properly
    
    considered Microsoft’s size and financial condition, as well as whether Microsoft
    
    investigated the scope of the patent.      Id. at 827; see also Transclean Corp. v.
    
    Bridgewood Servs., Inc., 
    290 F.3d 1364
    , 1377-78 (Fed. Cir. 2002).
    
          Microsoft is correct that it would have been improper to enhance damages based
    
    solely on litigation misconduct, and that this is not the prototypical case of litigation
    
    
    
    
    2009-1504                                  40
    misconduct. 5 Typically, “litigation misconduct” refers to bringing vexatious or unjustified
    
    suits, discovery abuses, failure to obey orders of the court, or acts that unnecessarily
    
    prolong litigation. Jurgens, 80 F.3d at 1570-71 & n.3; see also Va. Panel Corp. v. MAC
    
    Panel Co., 
    133 F.3d 860
    , 866 (Fed. Cir. 1997). Here, the misconduct was improper
    
    statements by Microsoft’s counsel to the jury, in defiance of the court’s repeated
    
    admonitions. However, the district court considered Microsoft’s litigation misconduct
    
    only after finding that the other Read factors favored enhanced damages: “Finally, also
    
    favoring enhancement is Microsoft’s counsel’s litigation conduct . . . .” Considering all
    
    the Read factors and the district court’s statutory authority to treble damages under
    
    § 284, the actual award of $40 million was not an abuse of discretion.
    
                                          VI. Willfulness
    
           We do not read Microsoft’s opening brief as challenging the denial of Microsoft’s
    
    post-verdict JMOL on willfulness.     Although Microsoft did mention willfulness when
    
    disputing the propriety of the enhanced damages award, in substance this argument
    
    focused on the district court’s rationale for awarding enhanced damages, not the jury’s
    
    willfulness verdict. Whether the district court abused its discretion in weighing the Read
    
    factors is not the same question as whether there was a legally sufficient evidentiary
    
    basis for the jury’s finding of willfulness. Fed. R. Civ. P. 50(a); compare Bryant v.
    
    Compass Group USA Inc., 
    413 F.3d 471
    , 475 (5th Cir. 2005), with Read, 970 F.2d at
    
    821, 826-27.     Whether Microsoft’s infringement was willful is a question of fact.
    
    
    
           5
                  Enhanced damages are certainly not the sole remedy for attorney
    misconduct. Other tools, which may be more appropriate in the mine-run of cases,
    include the award of attorney fees or sanctions. See 35 U.S.C. § 285; Fed. R. Civ. P.
    11, 38; see also 28 U.S.C. § 1927.
    
    
    
    2009-1504                                   41
    Cohesive Techs., Inc. v. Waters Corp., 
    543 F.3d 1351
    , 1374 (Fed. Cir. 2008); see
    
    Braun Inc. v. Dynamics Corp. of Am., 
    975 F.2d 815
    , 822 (Fed. Cir. 1992). This question
    
    was submitted to the jury, which answered in the affirmative. Accordingly, appellate
    
    review is limited to asking whether that verdict is supported by substantial evidence.
    
    ACCO Brands, 501 F.3d at 1311-12. On appeal, Microsoft has never attacked the jury
    
    instructions or the basis for the jury’s willfulness verdict.   In light of what Microsoft
    
    actually argued, we do not read Microsoft’s passing reference to its post-verdict JMOL
    
    on willfulness as raising the issue.
    
           Even if we were to read the solitary sentence, “Microsoft is entitled to judgment
    
    as a matter of law on the issue of willfulness,” as challenging the jury’s finding of
    
    willfulness, the result does not change. A reasonable jury could have concluded that
    
    Microsoft “willfully” infringed the ’449 patent based on the evidence presented at trial.
    
    Infringement is willful when the infringer was aware of the asserted patent, but
    
    nonetheless “acted despite an objectively high likelihood that its actions constituted
    
    infringement of a valid patent.”       Seagate, 497 F.3d at 1371.     After satisfying this
    
    objective prong, the patentee must also show that the infringer knew or should have
    
    known of this objectively high risk. Id.
    
           In this case, i4i presented sufficient evidence at trial to prove each prong of the
    
    Seagate standard for willfulness. The jury heard that Microsoft employees attended
    
    demonstrations of i4i’s software, which practiced the ’449 patent.       Further, the jury
    
    learned that Microsoft employees received i4i’s sales kit, which identified i4i’s software
    
    as “patented” technology and cited the ’449 patent. The jury then saw a series of
    
    emails between Microsoft employees discussing a marketing email sent by i4i. One of
    
    
    
    
    2009-1504                                    42
    those emails explained that the “heart” of i4i’s software was patented, again citing the
    
    ’449 patent. Based on this circumstantial evidence, the jury could have reasonably
    
    inferred that Microsoft knew about the ’449 patent.
    
           At trial, i4i also showed that Word’s custom XML editor was designed to and did
    
    perform the same methods as i4i’s software (which was known to practice the ’449
    
    patent). Despite this highly similar functionality, there is no evidence Microsoft took any
    
    remedial action, even though Microsoft knew of the ’449 patent as early as April 2001,
    
    before any work had begun on Word’s custom XML editor. For example, Microsoft did
    
    not cease its infringing activity or attempt to design around; instead, Microsoft started
    
    marketing, selling, and instructing others in the use of Microsoft’s custom XML editor in
    
    2002. Cf. DePuy Spine, Inc. v. Medtronic Sofamor Danek, 
    567 F.3d 1314
    , 1336-37
    
    (Fed. Cir. 2009). Similarly, there is no evidence Microsoft ever made a good faith effort
    
    to avoid infringement; internal emails show Microsoft intended to render i4i’s product
    
    “obsolete” and assure “there won’t be a need for [i4i’s] product.” Based on this and
    
    other evidence presented at trial, it would have been reasonable for the jury to infer that
    
    Microsoft went ahead with producing, marketing, and promoting its custom XML editor
    
    despite an objectively high likelihood the editor infringed the ’449 patent. This same
    
    evidence supports the jury’s finding as to the subjective prong of Seagate. Given the
    
    information Microsoft had about i4i’s software and the ’449 patent, Microsoft knew or
    
    should have known that there was an objectively high risk of infringement.
    
           The fact that Microsoft presented several defenses at trial, including
    
    noninfringement and invalidity, does not mean the jury’s willfulness finding lacks a
    
    sufficient evidentiary basis. See Fed. R. Civ. P. 50(a). The jury heard all of Microsoft’s
    
    
    
    
    2009-1504                                   43
    defenses, which it expressly rejected in finding the ’449 patent infringed and not invalid.
    
    Cf. DePuy Spine, 567 F.3d at 1336-37 (noting that the question of equivalence was “a
    
    close one”). Based on its own assessment of the evidence and Microsoft’s defenses,
    
    the jury was free to decide for itself whether Microsoft reasonably believed there were
    
    any substantial defenses to a claim of infringement. Cf. Cohesive Techs., 543 F.3d at
    
    1374.
    
                                    VII. Permanent Injunction
    
            We must decide whether the district court abused its discretion in granting a
    
    permanent injunction against Microsoft, or in tailoring that injunction under eBay Inc. v.
    
    MercExchange, L.L.C., 
    547 U.S. 388
    , 391 (2006).
    
            The permanent injunction prohibits Microsoft from (1) selling, offering to sell,
    
    and/or importing into the United States any infringing Word products with the capability
    
    of opening XML files containing custom XML; (2) using Word to open an XML file
    
    containing custom XML; (3) instructing or encouraging anyone to use Word to open an
    
    XML containing custom XML; (4) providing support or assistance that describes how to
    
    use Word to open an XML file containing custom XML; and (5) testing, demonstrating,
    
    or marketing Word’s ability to open an XML file containing custom XML.
    
            The scope of this injunction is narrow, however. It applies only to users who
    
    purchase or license Word after the date the injunction takes effect.           Users who
    
    purchase or license Word before the injunction’s effective date may continue using
    
    Word’s custom XML editor, and receiving technical support.
    
            We review the decision to grant an injunction, as well as the scope of that
    
    injunction, for abuse of discretion. Joy Techs., Inc. v. Flakt, Inc., 
    6 F.3d 770
    , 772 (Fed.
    
    
    
    
    2009-1504                                   44
    Cir. 1993). Factual findings made in support of the injunction are reviewed for clear
    
    error; the district court’s conclusion as to each eBay factor is reviewed for abuse of
    
    discretion. Acumed LLC v. Stryker Corp., 
    551 F.3d 1323
    , 1327-31 (Fed. Cir. 2008).
    
    Our review is guided by statute and well-established principles of equity. See 35 U.S.C.
    
    § 283. 6 The plaintiff has the burden of showing that (1) it has suffered an irreparable
    
    injury; (2) remedies available at law are inadequate to compensate for that injury; (3)
    
    considering the balance of hardships between the plaintiff and defendant, a remedy in
    
    equity is warranted; and (4) the public interest would not be “disserved” by a permanent
    
    injunction. eBay, 547 U.S. at 391.
    
          While we conclude that the injunction’s effective date should have been five
    
    months, rather than sixty days, from the date of its August 11, 2009 order, we affirm the
    
    district court’s issuance of a permanent injunction and otherwise affirm the injunction’s
    
    scope. Below, we address each factor in turn.
    
                                      A. Irreparable Injury
    
          The district court concluded that i4i was irreparably injured by Microsoft’s
    
    infringement, based on its factual findings that Microsoft and i4i were direct competitors
    
    in the custom XML market, and that i4i lost market share as a result of the infringing
    
    Word products.     The district court further found that the infringing Word products
    
    rendered i4i’s software obsolete, as a result of which i4i changed its business model to
    
    make software that complemented Microsoft’s infringing products.
    
    
    
    
          6
                  The Patent Act provides that courts “may grant injunctions in accordance
    with the principles of equity to prevent the violation of any right secured by patent, on
    such terms as the court deems reasonable.” 35 U.S.C. § 283.
    
    
    2009-1504                                  45
           It was proper for the district court to consider evidence of past harm to i4i. Past
    
    harm to a patentee’s market share, revenues, and brand recognition is relevant for
    
    determining whether the patentee “has suffered an irreparable injury.”           Id. at 391
    
    (emphasis added); see, e.g., Acumed, 551 F.3d at 1328-29 (considering the relevance
    
    of past licensing decisions in assessing irreparable injury); Voda v. Cordis Corp., 
    536 F.3d 1311
    , 1329 (Fed. Cir. 2008) (concluding that the patentee “had not identified any
    
    irreparable injury to himself”); Innogenetics, N.V. v. Abbott Labs., 
    512 F.3d 1363
    , 1379-
    
    80 (Fed. Cir. 2008) (analyzing whether the patentee “had been irreparably harmed”).
    
    Although injunctions are tools for prospective relief designed to alleviate future harm, by
    
    its terms the first eBay factor looks, in part, at what has already occurred. Considering
    
    past harm to a patentee does not establish a “general rule” or rely on the sort of “broad
    
    classifications” rejected by the Supreme Court in eBay; not all patentees will be able to
    
    show injury, and even those who do must still satisfy the other three factors. Cf. eBay,
    
    547 U.S. at 393-94.
    
           In this case, the district court properly considered strong circumstantial evidence
    
    that Microsoft’s infringement rendered i4i’s product obsolete for much of the custom
    
    XML market, causing i4i to lose market share and change its business strategy to
    
    survive. i4i was not required to prove that its specific customers stopped using i4i’s
    
    products because they switched to the infringing Word products.              Based on the
    
    evidence presented at trial, it was not an abuse of discretion for the district court to find
    
    that Microsoft’s infringement irreparably injured i4i.
    
                                 B. Inadequate Remedies at Law
    
    
    
    
    2009-1504                                    46
           The district court concluded that there were inadequate remedies at law to
    
    compensate i4i for its injury. The district court found that before and after Microsoft
    
    began infringing, i4i produced and sold software that practiced the patented method.
    
    The district court found no evidence that i4i had previously licensed the patent, instead
    
    finding evidence that i4i sought to retain exclusive use of its invention.
    
           It was not an abuse of discretion for the district court to conclude that monetary
    
    damages would be inadequate. In this case, a small company was practicing its patent,
    
    only to suffer a loss of market share, brand recognition, and customer goodwill as the
    
    result of the defendant’s infringing acts. Such losses may frequently defy attempts at
    
    valuation, particularly when the infringing acts significantly change the relevant market,
    
    as occurred here. The district court found that Microsoft captured 80% of the custom
    
    XML market with its infringing Word products, forcing i4i to change its business strategy.
    
    The loss associated with these effects is particularly difficult to quantify. Difficulty in
    
    estimating monetary damages is evidence that remedies at law are inadequate.
    
    Broadcom Corp. v. Qualcomm Inc., 
    543 F.3d 683
    , 703-04 (Fed. Cir. 2008).
    
                                     C. Balance of Hardships
    
           Except on the limited issue of timing, the balance of hardships favors i4i. The
    
    district court found that i4i’s business is comprised “almost exclusively” of products
    
    based on the ’449 patent. In contrast, Microsoft’s infringing custom XML editor was
    
    found to be “merely one of thousands of features” within Word, used by only a small
    
    fraction of Microsoft’s customers.      The district court further found that Microsoft’s
    
    infringement of the ’449 patent allowed Microsoft to “corner[] the XML market.”
    
    
    
    
    2009-1504                                    47
           Because the “balance of hardships” assesses the relative effect of granting or
    
    denying an injunction on the parties, the district court properly considered several
    
    factors in its analysis. eBay, 547 U.S. at 391. These factors included the parties’ sizes,
    
    products, and revenue sources. When measured by these factors, it is clear that the
    
    patented technology is central to i4i’s business. Because most of i4i’s products are
    
    based on the ’449 patent, i4i’s market share, revenues, and business strategy are
    
    similarly tied to the patented method. These same factors reveal that the infringing
    
    custom XML editor relates to only a small fraction of Microsoft’s sizeable business. The
    
    far greater importance of the patented method to i4i, combined with the demonstrated
    
    past effects of infringement on i4i, favors issuance of a permanent injunction.
    
           The district court’s analysis properly ignored the expenses Microsoft incurred in
    
    creating the infringing products. See Acumed, 551 F.3d at 1330. Similarly irrelevant
    
    are the consequences to Microsoft of its infringement, such as the cost of redesigning
    
    the infringing products. Id. As we explained in Broadcom, neither commercial success,
    
    nor sunk development costs, shield an infringer from injunctive relief. 543 F.3d at 704.
    
    Microsoft is not entitled to continue infringing simply because it successfully exploited its
    
    infringement. Id.; see also Windsurfing Int’l v. AMF, Inc., 
    782 F.2d 995
    , 1003 n.12 (Fed.
    
    Cir. 1986).
    
                                         D. Public Interest
    
           Except as to the injunction’s effective date, the district court did not abuse its
    
    discretion in finding that the narrow scope of the injunction and the public’s general
    
    interest in upholding patent rights favor injunctive relief. See Broadcom, 543 F.3d at
    
    704 (quoting Rite-Hite Corp. v. Kelley Co., 
    56 F.3d 1538
    , 1547 (Fed. Cir. 1995)). The
    
    
    
    
    2009-1504                                    48
    district court’s conclusion properly recognized that the touchstone of the public interest
    
    factor is whether an injunction, both in scope and effect, strikes a workable balance
    
    between protecting the patentee’s rights and protecting the public from the injunction’s
    
    adverse effects. Broadcom, 543 F.3d at 704. In particular, the injunction’s narrow
    
    scope substantially mitigates the negative effects on the public, practically and
    
    economically. By excluding users who purchased or licensed infringing Word products
    
    before the injunction’s effective date, the injunction greatly minimizes adverse effects on
    
    the public. Id. Here, the relevant “public” includes not only individual consumers, but
    
    also companies that license infringing Word products and manufacturers that are part of
    
    Microsoft’s distribution channels.    Cf. id. (defining the “public” to include affected
    
    network carriers and manufacturers). By carving out users who purchased or licensed
    
    infringing Word products before the injunction’s effective date, the injunction’s tailoring
    
    minimizes disruptions to the market and the public.
    
                                  E. Injunction’s Effective Date
    
           On appeal, Microsoft challenges the date on which the injunction goes into effect.
    
    We review whether this aspect of the district court’s order is supported by the record.
    
    As to the limited question of the injunction’s effective date, we conclude that it is not.
    
    Accordingly, the injunction’s effective date is modified as described below.
    
           The district court ordered the injunction to go into effect sixty days after August
    
    11, 2009, the date of its order issuing the injunction.        Citing the declaration of a
    
    Microsoft employee (the “Tostevin declaration”), the district court found that “Microsoft
    
    ha[d] presented evidence that it may take five months to implement any injunction.” The
    
    district court also found, without any citation to the record, that “i4i ha[d] presented
    
    
    
    
    2009-1504                                   49
    evidence that it is possible to design a software patch that can remove a user’s ability to
    
    operate the infringing functionality.” Based on, among other things, “this competing
    
    evidence” and “the uncertainty surrounding what period of time would be ‘reasonable’ to
    
    expect Microsoft to comply with any injunction,” the district court ordered Microsoft to
    
    comply with the permanent injunction “within 60 days.”
    
           In light of the record evidence, we conclude that the district court erred by
    
    ordering Microsoft to comply with the injunction within sixty days. The only evidence
    
    about how long it would take Microsoft to comply with the injunction was the Tostevin
    
    declaration, which gave an estimate of “at least” five months. The district court cited no
    
    other evidence, and our review of the record reveals no “competing evidence.”
    
    Accordingly, we modify the injunction’s effective date from “60 days from the date of this
    
    order” to “5 months from the date of this order.” Cf. Canadian Lumber Trade Alliance v.
    
    United States, 
    517 F.3d 1319
    , 1339 n.22 & 1344 (Fed. Cir. 2008) (modifying an
    
    injunction’s terms on appeal); Forest Labs., Inc. v. Ivax Pharms., Inc., 
    501 F.3d 1263
    ,
    
    1271-72 (Fed. Cir. 2007) (modifying an injunction’s terms on appeal). The injunction’s
    
    effective date is now January 11, 2010.
    
                                          CONCLUSION
    
           The district court’s claim construction is affirmed, as are the jury’s findings of
    
    infringement and validity. The district court did not abuse its discretion in admitting i4i’s
    
    evidence as to damages or in granting enhanced damages. Finally, we affirm the entry
    
    of the permanent injunction as modified herein.
    
                                            AFFIRMED
    
    
    
    
    2009-1504                                    50