A Brief Guide to Subsequent Patent Applications in the United States: Part I – The Foundation

“Many patent practitioners are not fully aware of the implications of subsequent applications, either for prosecution or for litigation.”

https://depositphotos.com/212778822/stock-photo-patent-applicaiton-approved-new-invention.htmlPatent practitioners (hopefully) know that there are many types of patent applications and, at times, have filed a continuation, continuation-in-part, or divisional application. “Continuation practice” was the once commonly used phrase to describe subsequent U.S. patent applications, which also used to include file wrapper continuations (FWC), now replaced by the more modern request for continued examination (RCE). These types of subsequent patent applications can be used strategically to build a portfolio of patents for a client for a given subject matter. See, e.g., the patents asserted in WesternGeco LLC v. ION Geophysical Corp., 585 U.S. ___, 138 S.Ct. 2129 (2018). However, many patent practitioners are not fully aware of the implications of each such subsequent application, either for prosecution or for litigation. This five-part series will review these types of applications and their implications and ultimately provide some relevant practice tips.

The Law

The filing of continuation, continuation-in-part, and divisional applications is limited by the co-pendency requirement of 35 U.S.C. § 120: each subsequent application cannot be filed after the issuance, expiration, or abandonment of the parent application from which it immediately depends. After issuance, for example, an applicant can only seek to add claims by filing a reissue application. 35 U.S.C. § 251. This piece will not address reissue applications, reexamination requests, post-grant proceedings, or requests for continuing examination (RCE).

A patent application may have its origins in one or more earlier filed applications. An applicant may file a continuation, divisional, or continuation-in-part (CIP) application of a prior application, all of which the U.S. Patent and Trademark Office (“USPTO”) characterizes as “continuing” applications. See MPEP § 201.11. The USPTO has also noted that the expressions “continuation,” “divisional,” and “continuation-in-part” are merely terms used for administrative convenience. See MPEP § 201.11; Transco Products Inc. v. Performance Contracting, Inc., 38 F. 3d 551,555 (Fed. Cir. 1994). In general, a continuing application is one filed during the pendency of another application which contains at least part of the disclosure of the other application and names at least one inventor in common with that application.

As discussed more fully herein, “continuation” and “divisional” applications are alike in that they are both continuing applications based on the same disclosure as an earlier application, without more. They differ, however, in what they claim. A “continuation” application comprises claims directed to the same invention claimed in an earlier application, although there may be some variation in the scope of the subject matter claimed. See MPEP § 201.07. A “divisional” application, on the other hand, is one carved out of an earlier application which disclosed and claimed more than one independent invention, the result being that the divisional application claims only one or more, but not all, of the non-claimed independent inventions of the earlier application. See MPEP § 201.06. A “CIP” application is a continuing application comprising all or a portion of the disclosure of an earlier application together with newly added matter not present in that earlier application. See MPEP § 201.08.4 The term “parent” is often used to refer to the immediately preceding application from which a continuing application claims priority; the term “original” is used to refer to the first application in a chain of continuing applications. See MPEP §§ 201.04, 201.04(a).

For these subsequent applications, U.S. Patent Law (unless noted otherwise, the “U.S. Patent Law” cited herein is the America Invents Act (AIA), implemented September 16, 2012, and applicable to all applications filed after March 16, 2013) requires that the subsequent (or “child”) patent application “contain a specific reference to [each] earlier filed application” to which it purports to claim priority. 35 U.S.C. § 120 (§120 became statutory law in 1952 and has its origins in patent office practice and case law – see Racing Strollers, Inc. v. TRI Indus., Inc., 878 F.2d 1418, 1421 (Fed. Cir. 1989)). For example, the Supreme Court, long ago, explained that under §120, parent and continuing applications “are to be considered as parts of the same transaction, and both as constituting one continuous application, within the meaning of the law.” Godfrey v. Eames, 68 U.S. 317, 326, 1 Wall. 317 (1863). Note, however, that these cases dealt only with the issue of priority, and not with USPTO procedure for examining a continuation application in light of its parent. For a specific reference to have effect, U.S. Patent Law provides that the application must be co-pending with one or more of the earlier-filed application(s), e.g. the first application of the family or one or more later-filed applications “similarly entitled” to the benefit of the first application’s filing date. 35 U.S.C. § 119 Although most commonly cited for non-provisional patent applications, 35 U.S.C. § 119(e)(1) recites parallel requirements to claim priority from an earlier-filed U.S. provisional application, stating “[n]o application shall be entitled to the benefit of an earlier filed provisional application … unless an amendment containing the specific reference to the earlier filed provisional application is submitted at such time during the pendency of the application as required by the Director.” However, as provisional patent applications cannot themselves be continuation, continuation-in-part, or divisional applications, this blog will not address provisional patent applications.

Understanding the Hierarchy

The authors note that in the hierarchy of binding authority, first there is the U.S. Constitution, followed by statutory laws such as the AIA (35 U.S.C. § 101 et seq.), and then case law interpreting and applying that law – these are primary, binding authorities. The regulations found in the U.S. Code of Federal Regulations (CFR) are considered as legally binding as any Federal Statute only if the given rule or regulation therein is a “reasonable interpretation” of the specific statute(s) enabling that rule or regulation (this is known as the “Reasonable Interpretation” rule). Along these lines, the AIA authorizes the USPTO to promulgate regulations governing the administration of certain proceedings, see, e.g., 35 U.S.C. § 316(a) (governing inter partes review under this chapter), and the Federal Circuit generally holds that “where a statute leaves a ‘gap’ or is ‘ambigu[ous],’ we typically interpret it as granting the agency leeway to enact rules that are reasonable in light of the text, nature, and purpose of the statute.” Cuozzo Speed Technologies, LLC v. Lee, 136 S. Ct. 2131,2142 (2016) (quoting United States v. Mead Corp., 533 U.S. 218, 229 (2001)). When the Board issues such rules, the Federal Circuit “accept[s] the Board’s interpretation of [them] unless that interpretation is ‘plainly erroneous or inconsistent with the regulation.’” In re Sullivan, 362 F.3d 1324, 1326 (Fed. Cir. 2004) (quoting Eli Lilly Co. v. Bd. of Regents of the Univ. of Wash., 334 F.3d 1264, 1266 (Fed. Cir. 2003)). On the other hand, “[t]he MPEP and Guidelines are not binding on court[s]” but they “may be given judicial notice to the extent they do not conflict with the statute.” In re Fisher, 421 F.3d 1365 (Fed. Cir. 2005). The authors therefore cite to the MPEP in this article as infrequently as we can.

The USPTO issued 37 C.F.R. § 1.78, which implements these statutes and requires that an application contain a specific reference to each prior-filed application to which the application seeks to claim priority. Specifically, §1.78 provides that the application claiming the benefit of one or more prior-filed, co-pending non-provisional applications must include “a reference to each such prior-filed application, identifying it by application number (consisting of the series code and serial number)” and indicating “the relationship of the applications (i.e., whether the later-filed application is a continuation, divisional, or continuation-in-part of the prior-filed nonprovisional application or international application).” 37 C.F.R. § 1.78(d)(3) (2009). Note that all the prior applications need not be co-pending. It further states that the reference “must be included in an application data sheet …, or the specification must contain or be amended to contain such reference in the first sentence(s) following the title.” Droplets, Inc. v. E* Trade Bank, 887 F.3d 1309,1316 (Fed. Cir. 2018). Consistent with 35 U.S.C. § 120 and 37 C.F.R. § 1.78, the MPEP provides detailed guidance on how to claim priority from multiple prior-filed applications. It states that “[t]he reference to the prior applications must identify all of the prior applications and indicate the relationship (i.e., continuation, divisional, or continuation-in-part) between each nonprovisional application in order to establish copendency throughout the entire chain of prior applications.” MPEP § 201.11 III.C.[3]

Chain of Priority

The Federal Circuit has noted that a patentee is the person best suited to understand the genealogy and relationship of her applications and, therefore, that a requirement for her to clearly disclose this information should present no hardship. Medtronic CoreValve v. Edwards Lifesciences Corp., 741 F. 3d 1359,1366 (Fed.Cir. 2014). However, although such a chain of priority should be specified upon filing the subsequent application, subsequently amending an application to change its relationship to a prior-filed application — for example, from a CIP application to a divisional application — is expressly permitted. In re Janssen Biotech, Inc., 880 F. 3d 1315,1324 (Fed.Cir. 2018), citing 37 C.F.R. § 1.78(d)(2) (2015) (providing that the specification must “contain or be amended to contain a reference to each such prior-filed application” and that “reference also must identify the relationship of the applications”) (emphasis added); see also MPEP § 211.03 (permitting the correction of “a timely submitted benefit claim” by “[c]hanging the relationship of the applications (e.g., changing … from ‘continuation-in-part’ to ‘continuation’ or ‘divisional’)”).

Language Matters

One further note: the Federal Circuit has used and interpreted the phrase “this application” in the self-referential sense to mean the “present application.” See, e.g., Santarus, Inc. v. Par Pharm., Inc., 694 F.3d 1344, 1360-61 (Fed.Cir.2012) (Newman, J., concurring-in-part and dissenting-in-part) (noting that the patent application properly claimed priority under § 120 when it disclosed all prior applications with “no break in the chain of priority” and concluded with, “This application claims priority to all such previous applications….”); Broadcast Innovation, L.L.C. v. Charter Commc’ns, Inc., 420 F.3d 1364, 1366 (Fed. Cir. 2005) (interpreting “[t]his application is a divisional” to set forth the priority chain of the present application); Zenon Envtl., Inc. v. U.S. Filter Corp., 506 F.3d 1370, 1383 (Fed.Cir.2007) (interpreting “[t]his application is a continuation of” to set forth the chain of co-pending applications from the present application). Nonetheless, “present application” is a phrase that should be used lightly, if at all, given that it can be applied to an application or issued patent to create disclaimers and estoppel. See “Avoiding the Present (Invention),” Patent, Trademark and Copyright Journal (BNA), February 17, 2006.

In Part II of this series, we will review the different types of subsequent applications.



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Join the Discussion

14 comments so far.

  • [Avatar for David Boundy]
    David Boundy
    January 16, 2021 04:44 pm

    Dear Gary and Jeff —

    The discussion of administrative law and rulemaking isn’t quite right. Lots of regulations are as binding as statute, even if they aren’t “reasonable interpretations.” Regulations are regulations, and Chevron-eligible interpretations are Chevron-eligible interpretations, two fundamentally different and analytically-distinct concepts, arising under two entirely different heads of authority (regulations are statutory, Chevron is purely common law). The two have some overlap, but that’s all that can be said.

    Judge Plager recommended that the patent bar would do well to read one of my articles, The PTAB is Not an Article III Court, Part 1: A Primer on Federal Agency Rule Making, Landslide (American Bar Ass’n), vol. 10, no. 2, pp. 9-13, 51-57 (Nov/Dec 2017), available at SSRN https://ssrn.com/abstract=3258044

    More detail on this topic is in The PTAB Is Not an Article III Court, Part 3: Precedential and Informative Opinions, 47 AIPLA Q.J. 1-99 (June 2019), updated edition available at SSRN https://ssrn.com/abstract=3258694

  • [Avatar for Jeffrey L. Wendt]
    Jeffrey L. Wendt
    December 14, 2020 07:17 pm

    Thanks for all the comments and discussion.

    Point well-taken with respect to the first comment. We probably should have finessed this more:

    Article: “A ‘continuation’ application ‘usually’ comprises claims directed to the same invention claimed in an earlier application, although there may be some variation in the scope of the subject matter claimed, ‘but neither law nor statue requires that the claims be directed to the “same invention.”‘ See MPEP § 201.07.” That said, the MPEP is not controlling, as one commenter noted.

    With respect to benefit claims, (Gary, my esteemed co-author may disagree) I always put the benefits claim(s) in the first sentence of the spec, despite what the MPEP may say about only the ADS having any significance. I have never had an examiner complain about it.

    10/4 on checking the Official Filing Receipt for errors. After many mis-spellings of inventors names by the PTO application pre-exam folks, I always use ALL CAPS in inventor names on the ADS.

  • [Avatar for Anon]
    October 12, 2020 08:55 pm

    Good point, ipguy.

  • [Avatar for ipguy]
    October 12, 2020 12:57 pm

    @8, 10

    The ADS is an official USPTO form. While it is referenced in the MPEP, a form is something separate and apart from the MPEP itself.

    Hard experience has taught me to always check the post-filing documents the USPTO sends you to confirm that the listed inventorship (and residence addresses), priority claim, entity status, etc. is correct. That is certainly the first place you’ll see whether or not the USPTO has recognized your priority claim.

    An improper priority claim in the ADS (and they happen for a number of reasons including two numbers being transposed or a number being left off; continuation being used instead of continuation-in-part, etc.) is much easier to fix if the specification has a priority claim with the correct US serial numbers.

  • [Avatar for Anon]
    October 12, 2020 11:25 am


    I just noticed your item (this may have been a first post from you, and there is typically some small delay for spam control on new posters).

    As you likely know, the MPEP is not controlling law for applicants. Note as well the additional ‘permissive’ language in the MPEP section that you provided: … are ALSO presented…

    This is an administrative notice of how the Office has stated it will process certain information. Like other (and other substantive points), the MPEP may well be legally incorrect, and in such cases, very much sets a trap for the unwary.

  • [Avatar for ipguy]
    October 9, 2020 04:18 pm

    Count your blessings.

  • [Avatar for Bluesky]
    October 9, 2020 01:46 pm

    Anon @ 4. I always put the priority chain in the first sentence and had this issue brought up by an examiner, although in my case the examiner quickly backed off.

    On the USPTO forms page, the Instructions for Application Data Sheet (ADS) 37 CFR 1.76 Updated November 16, 2015 states near the bottom of page 5 “Note for applications filed on or after September 16, 2012: Domestic benefit claims must be presented in the Application Data Sheet only. Domestic benefit information provided in the first sentence(s) of the specification will not be recognized by the Office unless the domestic benefit claims are also presented in the Application Data Sheet.”

    There is underlining and bold font in the original, including the first phrase and the word “only.” I know that in court the MPEP is not controlling. Would these instructions be controlling? I can see a time coming when some poor patent attorney finds out that by leaving the chain of priority out of the specification, an infringer challenges the priority claim which is only in the ADS. Will the infringer win and have the patent invalidated over its parent which becomes prior art?

    This is sort of like a specification issue in US District Court for the Northern District of California in case no. 01-CV-4204. Judge Seeborg ruled that circuit schematic shown in the patent drawings were not considered to be part of the specification and thus could not support a claim element. That a schematic diagram of a claimed circuit is not a sufficient disclosure, proves once again ladies and gents that the belt and suspenders approach to writing patent applications is best. Put it all in the written specification, even if it is redundant.

  • [Avatar for Anon]
    October 9, 2020 07:50 am

    Thanks, ipguy. I have to wonder how widespread that is, as most of the dealings that I have had with such clerical staff (and a bunch of recent ones dealing with a transferred-in portfolio) have been in the opposite direction.

  • [Avatar for Pro Say]
    Pro Say
    October 8, 2020 08:47 pm

    Nice job guys — thanks. Looking forward to the entire series.

    I would just point out one “nuance” concerning divisionals.

    You state, “A ‘divisional’ application, on the other hand, is one carved out of an earlier application which disclosed and claimed more than one independent invention … ”

    In addition to requiring a divisional in the event of two or more claimed independent (i.e. unrelated) inventions in the same application, the Office may also require (subject to applicant’s rebuttal / traversal) one or more divisionals in the event of an application when two or more distinct (i.e., related but patentably distinct) inventions are claimed in the same application:


  • [Avatar for ipguy]
    October 8, 2020 08:11 pm

    I apologize for some lack of clarity on my part. I wasn’t trying to imply that including a priority claim paragraph shouldn’t be done. I’m one of the practitioners that includes it. When I said, the USPTO doesn’t event want applicants to include the priority claim, I wasn’t speaking in terms of stated USPTO policy. It’s based on “unofficial” policy from my experiences with USPTO clerical personnel a few times when I tried to submit a Preliminary Amendment amending the spec to include a priority claim in a continuation application. When I stated that the rules indicate that a prior claim should be included in the specification, USPTO personnel were insistent that amending the specification was not necessary, that they don’t want or need it, and all that mattered was the priority claim was in the ADS. You can point to 37 CFR 1.78 (a)(3),(d)(2), and (h) to your hearts content, and you will still get an insistence that all that matter is the ADS. I’ve learned to never argue with USPTO clerical personnel. Just thank them politely for their time, and move on.

  • [Avatar for Anon]
    October 8, 2020 07:02 pm


    I found your comment of “The USPTO doesn’t even want applicants to include a priority claim section at the beginning of the specification when the application is filed” more than a bit interesting, as I have very much seen the opposite (and across the board, from the Office to the clients, wanting this to be done – and to be done correctly).

    Not saying that you are wrong, per se – but would be interested in any Office statements in support of that position.

  • [Avatar for ipguy]
    October 8, 2020 03:54 pm

    I don’t mean to be nit-picky but the “Language Matters” section fails to discuss that the language in the Application Data Sheet with regard to claiming the benefit of priority is what really matters these days. From what I’ve seen, the ADS is where the USPTO is pulling it’s priority claim language from for use in published applications and issued patents. The USPTO doesn’t even want applicants to include a priority claim section at the beginning of the specification when the application is filed (though many practitioners still include one just in case there is an ADS screw-up).

  • [Avatar for Anon]
    October 8, 2020 12:40 pm

    Mr. Doerre,

    I concur that that section appears to be a bit messy.

    It may also help to note that Divisionals are typically at the direction of the Patent Office, as a result of Restriction Requirements – and such restriction requirements carry with them an admission from the Office that the resulting items are patentably distinct, and thus no ‘joinder’ of the products (end patents) is required.

  • [Avatar for J. Doerre]
    J. Doerre
    October 8, 2020 09:33 am

    Article: “A ‘continuation’ application comprises claims directed to the same invention claimed in an earlier application, although there may be some variation in the scope of the subject matter claimed. See MPEP § 201.07.”

    This seems misleading, particularly when juxtaposed with the very next claim that “[a] ‘divisional’ application, on the other hand, is one carved out of an earlier application which disclosed and claimed more than one independent invention.” The implication seems to be that a continuation must have “claims directed to the same invention claimed in an earlier application.”

    However, MPEP 201.07 makes clear that “[a] continuation application is an application for the invention(s) disclosed in a prior- … application.”

    That is, what is relevant for a continuation is that it claim one or more “invention(s) disclosed in a prior- … application,” MPEP 201.07, not that it have “claims directed to the same invention claimed in an earlier application.”