Certificates of Correction 2021

by Dennis Crouch

For the most part, Certificates of Correction are boring, simple, and quite common. 35 U.S.C. § 254 & 255 provide for correction of minor mistakes by the PTO and applicant respectively.  PTO mistakes are fixed when a mistake is “clearly disclosed by the records of the Office.”  For applicant-mistakes, the correction is allowed for “clerical or typographical nature, or of minor character” made in good faith.  Larger mistakes should be corrected via Reissue.  Errors can also be corrected as part of a reexamination or AIA trial (such as inter partes review).  In most cases applicants prefer the certificate of correction route because the procedures and approval process tend to be much more patentee friendly.  And, the minor corrections are more likely to have retroactive effect against past infringers.

The PTO grants the vast majority of requests for correction.  The most common denials are based upon the patentee’s failure to submit the correct forms.

Chart showing certificates of correction per year

The chart above shows the number of certificates of correction issued by the USPTO each year with a forecast through the end of 2021.* The chart shows a fairly small downward trend over the past several years.  Although the trend above is fairly small, I believe that it will actually prove dramatic — with a ~50% reduction in the number of corrections issued moving forward.  We can see forecast with some more clarity in the chart below.

The next chart shows the percentage of patents that have been corrected (patents grouped according to the date they issued).  Since this data only goes through March 31, 2021, only a very small percentage of patents issued in 2021 have been corrected. There simply has not been enough time for the patents to issue and be corrected within this three month period.  On the other hand, the pre-2020 data is fairly accurate because  85%+ of corrections are typically issued within the first two-years of issuance.**

I wrote above that patentees would generally prefer to amend claims as part of a certificate of correction rather than within an AIA trial.  The correction process is simpler, there is no opposing party, and the PTO rarely demands much evidence.

In Honeywell Intl. Inc. v. Arkema Inc., 939 F.3d 1345 (Fed. Cir. 2019), the Federal Circuit chastised the PTAB for creating roadblocks against a patentee from seeking correction in the midst of an AIA Trial.  The court explained that “the Director has not delegated its Section 255 authority to the Board.”  Id.  After the court decision, Honeywell was permitted by the PGR Panel to file a petition for Certificate of Correction of the priority claims.  “Honeywell’s mistake was inadvertently, i.e., unintentionally, failing to include a claim to the priority of three other Honeywell applications.” The petition was filed in May 2020 and is still pending before the Petitions Office.

There are currently dozens of certificate of correction fights going on within AIA trials (IPRs and PGRs).  Basic questions in the cases: (1) When should the PTAB permit a certificate of correction to be filed; (2) Should the PTAB await the outcome of the correction petition before issuing a final written decision; (3) Will the correction be given retroactive effect?

In the recent decision in Election Sys. & Software, LLC v. Hart Intercivic, Inc., PATENT 10,445,966 B1, 2021 WL 409335, at *4 (Patent Tr. & App. Bd. Feb. 5, 2021), the Board permitted the patentee to seek a certificate of correction as follows:

 The method of claim 25, wherein the data set wherein includes a candidate’s name . . .

Here, the second “wherein” was clearly a typo and the petitions office agreed to the correction.  When the correction got back to the Board, the panel refused to take the correction into account — explaining that “shifting the scope of this proceeding to consider the corrected claims could impede the Board’s ability to meet its statutory deadlines. By declining to give effect to the correction, we keep the proceeding properly moored to the Petition that was the basis for instituting this trial.”  A final written decision is not yet issued in the case.

SIPCO, LLC v. Emerson Elec. Co., No. 2018-1364 (Fed. Cir. May 3, 2018) involves a situation where the Certificate of Correction issued after the PTAB decision cancelling the claims, but before the appeal was heard.  Rather than deciding the case, the Federal Circuit ordered the PTAB to address “what, if any, impact the certificate of correction has on its final written decision in this case.” Id.   On remand, the PTAB held that

the Certificate, which issued after the Final Decision and after Patent Owner filed an appeal to the Federal Circuit, has no impact on the Final Decision in this case because it was not in effect during the proceeding.

Emerson Elec. Co. v. Sipco, LLC, IPR2016-00984, 2020 WL 407144, at *8 (Patent Tr. & App. Bd. Jan. 24, 2020). The Federal Circuit then affirmed the case without opinion.  There were several reasons why the Federal Circuit may have affirmed and therefore we don’t know their thoughts on the issue.  It also is not clear whether the correct claims can now be asserted (even retroactively).

= = = = =

* The first chart includes all certificates of correction for utility patents. About 5% of patents are associated with two or more certificates of correction.  Those are included within the first chart. I excluded those figures from the second chart which shows the percentage of patents with at least one certificate of correction.

** The large bump of 2009 patents was associated with a retroactive change in patent term adjustment calculation.  A cumulative frequency chart is provided below using certificates of correction issued Jan 2014 through March 2021.

17 thoughts on “Certificates of Correction 2021

  1. 3

    No mention here of how Article III courts have treated certificates of correction issued after the onset of litigation.

    “By declining to give effect to the correction, we keep the proceeding properly moored to the Petition that was the basis for instituting this trial.”

    The facts that were the basis for instituting the “trial” (I hesitate to use the word, because PTAB is not an Article III court) ceased to exist once the certificate of correction was granted. So this rationale constitutes idiocy and/or sloppy thinking and/or laziness on the part of the PTAB…but does it track how courts have approached this? A better way for the PTAB to have stated it, if the PTAB proceedings were instituted following the filing of an infringement complaint in district court, might have been, “You should have sought that correction before you filed the infringement complaint; but since you made your bed this way, now you have to lie in it.” That same reasoning would not apply, however, where the PTAB instigator was the party that picked the fight.

    The practice tip for would-be plaintiff patentees is clear: check your claims and if necessary get them corrected before you try to assert your patent.

    1. 3.1

      Yes we were discussing this same point—CoCs in ongoing infringement litigation—a little below.

    2. 3.2

      “The practice tip for would-be plaintiff patentees is clear: check your claims and if necessary get them corrected before you try to assert your patent.” [With certificates of correction where possible, but those rarely fix serious claim problems.]
      That point has been made several times in comments here, yet is widely ignored by attorneys and clients. Ignored as to reissues [to add or amend claims] even before reexaminations, much less now – facing potential IPRs in response to suits. A frequent excuse is losing “intervening rights. ” But that partial restriction on potential back damages has to be properly weighed against the risk of losing all rights without any claim changes. Another example of why it is desirable to get an independent second opinion from a patent litigation expert before suing, from someone not anticipating large billings by the suit.

  2. 2

    Generally speaking, a missing priority claim is definitely not a “minor mistake of a clerical nature” that can be corrected by certificate.

    What are the facts of the Honeywell case?

    1. 2.1

      So, Honeywell did concede it wasn’t a clerical (or typographical) error, so those were definitely off the table. But is that right about it not being of minor character either? While I haven’t studied them closely, MPEP §§ 211.02(a) and 1481.03 at least seem to suggest that a CoC may be appropriate for that in some instances. That may also explain why the petition is still pending instead of being rejected out of hand.

      A link to the case is below. It’s not very long, and if you have a look, you’ll see that the procedural posture was sort of weird. The Board rejected the CoC on the merits, and while CAFC didn’t agree, it didn’t reverse outright. Instead, it remanded to the Board solely to consider whether to allow Honeywell to petition the Director for a CoC. While CAFC wasn’t totally clear on this point, it appears that inquiry uses a less demanding standard of simply asking whether a “sufficient basis” exists to petition for a CoC. Again, seeing as the petition was ultimately permitted to be filed, I think you can infer that at least a “sufficient basis” did exist (that the alleged error was of minor character).

      link to casetext.com

      1. 2.1.1

        The MPEP makes adding a claim for priority a trivial thing that can be fixed with a CoC. Deleting a claim for priority gets into Reissue world because in that case (1) you are trying to extend the term of a patent that has already been issued and (2) the application was not examined for the later effective filing date.


          That continues to be my impression w.r.t. adding via a CoC. I also found a law firm bulletin that agrees. But there just doesn’t seem to be any case-law squarely addressing the issue. Maybe it’s because people are usually good about making sure all priority claims are included before issuance? 🙂

      2. 2.1.2


        I do have an issue with this Honeywell assertion: “Honeywell also argued that this change was “minor” because it did not change the substance of the claims or the specification. J.A. 155:13–25.

        Since we DO have a ‘no new matter” rule, and since – as adjudicated – the existing specification was NOT sufficient**, and that the change was necessary to ‘fill this gap,’ this MUST BE a substantive change to the specification as filed. In other words, if NOT new matter, then the link back would not be necessary for the asserted support – and would be necessary only for the priority timing.

        ** I think though that this is NOT a thing that has actually been decided – and would be decided DURING the decision to allow or not allow a CoC.

        Of course, there is shared blame here, as if the examiner were on the ball and had rejected the claims during prosecution, the error in priority claiming could have been dealt with prior to issue and subsequent enforcement efforts. Note that this is ‘blame’ and not “fault’ (in the 35 USC 255 sense).

        Interestingly enough, this “blame” actually appears to SAVE the patentee, as MPEP 1481 as written (I have not verified with a direct case reading) states (emphasis added):

        See Novo Industries, L.P. v. Micro Molds Corporation, 350 F.3d 1348, 69 USPQ2d 1128 (Fed. Cir. 2003) (The Federal Circuit stated that when Congress in 1952 defined USPTO authority to make corrections with prospective effect, it did not deny correction authority to the district courts. A court, however, can correct only if “(1) the correction is not subject to reasonable debate based on consideration of the claim language and the specification and (2) the prosecution history does not suggest a different interpretation…” ). SINCE the prosecution history did NOT flag this as new matter, then a presumption is created that this type of correction is at least colorable.

        Nonetheless, the linked case of Honeywell IS focusing on a very specific and procedural point.

        I think that THIS does violate the asserted holding tracing back to Ultratec (““The patentee must show that the mistake “occurred in good faith” and that “the correction does not involve such changes in the patent as would constitute new matter or would require re-examination.” Honeywell Int’l Inc. v. Arkema Inc., 939 F.3d 1345, 1348 (Fed. Cir. 2019)

        Here, it seems that the formalities are at point (Means must be proper). Note: “The Director has not delegated its Section 255 authority to the Board, but has instead promulgated procedures by which patentees may seek the Board’s leave to petition the Director for a Certificate of Correction. 37 C.F.R. § 1.323 ; MPEP § 1485.” Honeywell Int’l Inc. v. Arkema Inc., 939 F.3d 1345, 1349 (Fed. Cir. 2019)


        By requiring that Honeywell “show that [the] requirements of 255 have been met” before authorizing Honeywell to file a motion for leave to seek a Certificate of Correction from the Director, the Board abused its discretion. The Board further abused its discretion by assuming the authority that § 255 delegates to the Director and deciding the merits of Honeywell’s petition for a Certificate of Correction. Honeywell Int’l Inc. v. Arkema Inc., 939 F.3d 1345, 1350 (Fed. Cir. 2019).

    2. 2.2

      “A missing priority claim is definitely not a “minor mistake of a clerical nature” [correctable by a certificate of correction]. My reaction as well.
      But if a patent owner does obtain ex parte an improperly-allowed, even non-statutory, CoC from the PTO before suit, can that be challenged in litigation on that patent? Does this not raise issues with CAFC decisions denying challenges to improper PTO application abandonment revivals, etc.?

      1. 2.2.1

        But if a patent owner does obtain ex parte an improperly-allowed, even non-statutory, CoC from the PTO before suit, can that be challenged in litigation on that patent?

        I believe that the answer is no (based on my recollection of similar types of challenges against the patent office for reinstating abandoned applications).


          I had the same initial reaction as Curious and Paul Morgan, but again, the MPEP sections and the actual facts in Honeywell seem to suggest otherwise. Let me know if anyone has a definitive answer and maybe I’ll have to seek a CoC for my comment (CoCC?).

          As to Paul’s first question, I have seen at least one instance of Art. III litigation where one of the asserted patents had a CoC made prelitigation, and the CoC was later challenged during the litigation as allegedly improper. The challenge ultimately failed on the merits, but it is possible to make one as a procedural matter.

  3. 1

    These are some fun statistics. It got me curious about what happens to a CoC issued in the midst of ongoing district court litigation. Per some cursory research (link below), it seems like the belated CoC is not considered in that case, which seems generally consistent with the PTAB approach.

    link to finnegan.com

      1. 1.1.1

        . . . and after reading that Overstock case, now I’m wondering whether the corrected patent could be asserted in court against a different infringer. (and not sure how a (new) IPR or PGR on the same patent / same (or different) claims would interplay . . .)

        Thoughts anyone?


          The very short time slot for filing PGRs – running from the patent issue date – usually precludes their availability. As to IPRs, these days a second IPR attempted on the same patent, even by a second party, might face discretionary institution refusal without good justification for it.


            … or it may not, depending on the vagaries of the most political of the three branches — and for an administrative agency that has one of the thinnest separations OF the political from its “Fourth Branch” adjudicatory functions.

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