{"id":1479,"date":"2026-06-17T13:20:04","date_gmt":"2026-06-17T13:20:04","guid":{"rendered":"https:\/\/www.perspireip.com\/blog\/terminal-disclaimer-double-patenting\/"},"modified":"2026-06-17T13:44:00","modified_gmt":"2026-06-17T13:44:00","slug":"terminal-disclaimer-double-patenting","status":"publish","type":"post","link":"https:\/\/www.perspireip.com\/blog\/terminal-disclaimer-double-patenting\/","title":{"rendered":"Terminal Disclaimer: 3 Hidden Costs and When to File"},"content":{"rendered":"\n<div class=\"wp-block-rank-math-toc-block\" id=\"rank-math-toc\"><h2>Table of Contents<\/h2><nav><ul><li class=\"\"><a href=\"#what-is-a-terminal-disclaimer\">What Is a Terminal Disclaimer?<\/a><\/li><li class=\"\"><a href=\"#how-disclaimers-defeat-double-patenting\">How Disclaimers Defeat Double Patenting<\/a><\/li><li class=\"\"><a href=\"#when-you-actually-need-to-file-one\">When You Actually Need to File One<\/a><\/li><li class=\"\"><a href=\"#what-it-really-costs-you\">What It Really Costs You<\/a><\/li><li class=\"\"><a href=\"#the-2024-rule-that-almost-changed-everyt\">The 2024 Rule That Almost Changed Everything<\/a><\/li><li class=\"\"><a href=\"#how-to-file-one-correctly\">How to File One Correctly<\/a><\/li><li class=\"\"><a href=\"#alternatives-worth-considering-first\">Alternatives Worth Considering First<\/a><\/li><li class=\"\"><a href=\"#how-perspireip-can-help\">How PerspireIP Can Help<\/a><ul><li class=\"\"><a href=\"#t1\">Does a terminal disclaimer shorten my patent&#8217;s term?<\/a><\/li><li class=\"\"><a href=\"#t2\">What is the difference between statutory and nonstatutory double patenting?<\/a><\/li><li class=\"\"><a href=\"#t3\">Can I file a terminal disclaimer over someone else&#8217;s patent?<\/a><\/li><li class=\"\"><a href=\"#t4\">Did the USPTO change the terminal disclaimer rules in 2024?<\/a><\/li><li class=\"\"><a href=\"#t5\">Can a terminal disclaimer be undone after it is recorded?<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n\n\n\n<p>You open an Office Action, scan past the prior-art rejections, and find a line that looks almost harmless: an obviousness-type double patenting rejection over your own earlier patent. Your examiner suggests an easy fix, just file a <strong>terminal disclaimer<\/strong>. One short form, no fee fight, rejection gone. But that one-page form is one of the most consequential documents you will ever sign in prosecution. It can shorten your patent term, bind two patents together for life, and quietly reshape how enforceable your portfolio is. Before you sign, it pays to understand exactly what you are giving up.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"what-is-a-terminal-disclaimer\">What Is a Terminal Disclaimer?<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1200\" height=\"600\" src=\"https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig1.jpg\" alt=\"What Is a Terminal Disclaimer? \u2014 terminal disclaimer\" class=\"wp-image-1485\" srcset=\"https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig1.jpg 1200w, https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig1-300x150.jpg 300w, https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig1-1024x512.jpg 1024w, https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig1-768x384.jpg 768w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">What Is a Terminal Disclaimer?<\/figcaption><\/figure>\n\n\n\n<p>A <strong>terminal disclaimer<\/strong> is a statement, authorized by <a href=\"https:\/\/www.law.cornell.edu\/uscode\/text\/35\/253\" target=\"_blank\" rel=\"noopener\">35 U.S.C. \u00a7 253<\/a> and governed by <a href=\"https:\/\/www.law.cornell.edu\/cfr\/text\/37\/1.321\" target=\"_blank\" rel=\"noopener\">37 CFR 1.321<\/a>, in which a patent owner gives up (&#8220;disclaims&#8221;) the tail end of a patent&#8217;s term so that it expires on the same day as a related patent. In plain terms, you are agreeing that your later patent will not outlive the earlier one it is tied to.<\/p>\n\n\n\n<p>It does two things at once. First, it lines up the expiration dates of the two patents. Second, and this is the part applicants often miss, it adds a binding condition: the disclaimed patent is enforceable only for as long as both patents remain <em>commonly owned<\/em>. Split the ownership, and you can lose the ability to enforce the later patent at all.<\/p>\n\n\n\n<p>Examiners propose terminal disclaimers so routinely that they can feel like a formality. They are not. Once recorded, the disclaimer is extremely difficult to undo, the USPTO will only withdraw one in narrow circumstances, so the decision to file is effectively permanent.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"how-disclaimers-defeat-double-patenting\">How Disclaimers Defeat Double Patenting<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1200\" height=\"600\" src=\"https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig2.jpg\" alt=\"How Disclaimers Defeat Double Patenting \u2014 terminal disclaimer\" class=\"wp-image-1486\" srcset=\"https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig2.jpg 1200w, https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig2-300x150.jpg 300w, https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig2-1024x512.jpg 1024w, https:\/\/www.perspireip.com\/blog\/wp-content\/uploads\/terminal-disclaimer-double-patenting-fig2-768x384.jpg 768w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption class=\"wp-element-caption\">How Disclaimers Defeat Double Patenting<\/figcaption><\/figure>\n\n\n\n<p>Almost every disclaimer exists to solve one problem: <strong>double patenting<\/strong>. There are two flavors, and only one of them can be cured with a disclaimer.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Statutory (same-invention) double patenting<\/strong> under 35 U.S.C. \u00a7 101 arises when two patents claim the identical invention. A terminal disclaimer cannot fix this, you must amend or cancel claims.<\/li><li><strong>Nonstatutory (obviousness-type) double patenting<\/strong>, or ODP, arises when the claims of a later patent are not identical but are an obvious variant of an earlier commonly-owned patent. This is the rejection a terminal disclaimer is designed to overcome.<\/li><\/ul>\n\n\n\n<p>ODP rejections show up most often when you build a patent family, the exact scenario created by continuation practice. If you are pursuing layered protection through continuations, double patenting rejections are not a sign you did something wrong; they are a predictable byproduct of claiming related subject matter across multiple filings. (For the bigger picture on family strategy, see our guide on <a href=\"https:\/\/www.perspireip.com\/blog\/continuation-patents-when-and-how-to-file\/\">continuation patents and when to file them<\/a>.)<\/p>\n\n\n\n<p>The policy behind the rule is simple: you should not be able to extend your effective monopoly on one invention by spreading obvious variations across several patents with staggered expiration dates. The terminal disclaimer enforces that by collapsing the expiration dates back together.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"when-you-actually-need-to-file-one\">When You Actually Need to File One<\/h2>\n\n\n\n<p>You need one when an examiner issues an ODP rejection that you have decided not to fight, and only if a few conditions are met. In our experience, filing makes sense in these situations:<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li><strong>The rejection is sound and the cited patent is yours.<\/strong> The reference patent must be commonly owned (or subject to a joint research agreement). A terminal disclaimer over a third party&#8217;s patent is not an option.<\/li><li><strong>The reference patent is still in force.<\/strong> Per MPEP 804, a terminal disclaimer is ineffective if the reference patent has already expired, you cannot disclaim term against a patent that is already dead.<\/li><li><strong>Losing the tail-end term doesn&#8217;t hurt you.<\/strong> If the two patents already share nearly the same priority date, the term you give up may be small or zero.<\/li><li><strong>Speed and cost matter more than term.<\/strong> A disclaimer ends the rejection immediately without the back-and-forth of arguing claims.<\/li><\/ol>\n\n\n\n<p>If any of those conditions fails, especially if the rejection is weak or the lost term is valuable, filing reflexively is a mistake. The disclaimer is the fast path, not always the right one.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"what-it-really-costs-you\">What It Really Costs You<\/h2>\n\n\n\n<p>The USPTO filing fee for one is modest, currently $200, and the agency eliminated that fee for disclaimers filed during prosecution in recent fee rulemaking, so check the <a href=\"https:\/\/www.uspto.gov\/learning-and-resources\/fees-and-payment\/uspto-fee-schedule\" target=\"_blank\" rel=\"noopener\">current USPTO fee schedule<\/a> before you assume a number. But the filing fee is the least important cost. The real price is paid in three other currencies.<\/p>\n\n\n\n<p><strong>Lost patent term.<\/strong> If your later patent would otherwise have expired after the reference patent, you forfeit that difference. With continuation chains stretching years apart, that can mean handing the public extra time at the end of your most valuable patent.<\/p>\n\n\n\n<p><strong>Forfeited patent term adjustment.<\/strong> A disclaimer can wipe out PTA you earned for USPTO delay, because you cannot recapture term beyond the date you disclaimed to. Inventors are often surprised that a routine disclaimer erases months of hard-won adjustment.<\/p>\n\n\n\n<p><strong>A permanent common-ownership leash.<\/strong> Because the disclaimed patent is enforceable only while it stays commonly owned with the reference patent, the two can never be sold or assigned separately without jeopardizing enforceability. That constrains licensing, divestitures, and how you carve up a portfolio in an acquisition, a real consideration in any <a href=\"https:\/\/www.perspireip.com\/blog\/ip-due-diligence\/\">IP due diligence review<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"the-2024-rule-that-almost-changed-everyt\">The 2024 Rule That Almost Changed Everything<\/h2>\n\n\n\n<p>Terminal disclaimer practice nearly underwent its biggest shift in decades. On May 10, 2024, the USPTO published a proposed rule (89 Fed. Reg. 40439) that would have added a sweeping new condition: a patent tied by such a disclaimer would become <em>unenforceable<\/em> if any claim in the linked patent was ever held unpatentable or invalid under \u00a7 102 or \u00a7 103. In effect, one invalidated claim in a family could topple every patent disclaimed to it.<\/p>\n\n\n\n<p>The proposal drew fierce opposition. After receiving more than 300 comments, the USPTO <a href=\"https:\/\/www.federalregister.gov\/documents\/2024\/12\/04\/2024-28263\/terminal-disclaimer-practice-to-obviate-nonstatutory-double-patenting-withdrawal\" target=\"_blank\" rel=\"noopener\">formally withdrew the rule on December 4, 2024<\/a>, citing resource constraints. So as of today, the rule never took effect, and terminal disclaimers carry only the long-standing common-ownership enforceability condition, not the proposed invalidity-linkage condition.<\/p>\n\n\n\n<p>The lesson for portfolio owners is that this area is politically live. The underlying concern, that disclaimer chains let owners stack obvious variants, has not gone away. Treat aggressive continuation-plus-disclaimer strategies as something to revisit, not set and forget.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"how-to-file-one-correctly\">How to File One Correctly<\/h2>\n\n\n\n<p>Mechanically, filing is straightforward. Most practitioners use the USPTO&#8217;s eTerminal Disclaimer (eTD) tool, which auto-populates and approves a compliant disclaimer almost instantly. The essentials:<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>Identify the reference patent or application you are disclaiming over, and confirm common ownership.<\/li><li>State that the later patent will expire on the same date as the reference patent (or be disclaimed to its term), and include the required common-ownership enforceability language from 37 CFR 1.321.<\/li><li>Have a person authorized to sign, the applicant or attorney of record, execute it.<\/li><li>Pay the applicable fee (verify the current amount) and file through Patent Center or the eTD tool.<\/li><li>Confirm the disclaimer is recorded; the examiner will then withdraw the ODP rejection.<\/li><\/ol>\n\n\n\n<p>Get the reference patent identification or the statutory language wrong and the disclaimer can be defective, which is exactly the kind of avoidable error that surfaces later during litigation.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"alternatives-worth-considering-first\">Alternatives Worth Considering First<\/h2>\n\n\n\n<p>Before you disclaim, ask whether you even should. Seasoned prosecutors weigh several alternatives:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Traverse the rejection.<\/strong> If the later claims are genuinely patentably distinct, argue ODP does not apply, no term is lost if you win.<\/li><li><strong>Amend the claims.<\/strong> Narrowing or differentiating the claims can remove the obviousness overlap that triggered the rejection.<\/li><li><strong>Pursue a restriction or different claim scope.<\/strong> Sometimes the cleaner answer is to reshape what each patent in the family covers so they no longer collide.<\/li><li><strong>Disclaim deliberately, with eyes open.<\/strong> When the term loss is trivial and speed matters, a disclaimer is the efficient choice, just make it a decision, not a reflex.<\/li><\/ul>\n\n\n\n<p>The right move depends on how much term is at stake, how strong the rejection is, and how you plan to license or sell the patents later. That is a judgment call, not a form-filling exercise.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"how-perspireip-can-help\">How PerspireIP Can Help<\/h2>\n\n\n\n<p>Deciding whether to file a <strong>terminal disclaimer<\/strong>, or fight the rejection instead, is exactly the kind of call that can quietly add or subtract years of protection from your most important patents. At <strong>PerspireIP<\/strong>, our team helps inventors and businesses navigate double patenting rejections, prior-art and patentability searches, and portfolio-wide IP strategy, so you protect term where it matters and concede it only where it doesn&#8217;t. <a href=\"https:\/\/www.perspireip.com\/contact\">Talk to our team<\/a> about your prosecution or portfolio strategy.<\/p>\n\n\n\n<p><em>This article is general information about U.S. patent practice, not legal advice. Consult a qualified patent attorney about your specific application.<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"faq\">Frequently Asked Questions<\/h2>\n\n\n<div id=\"rank-math-faq\" class=\"rank-math-block\">\n<div class=\"rank-math-list \">\n<div id=\"t1\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">Does a terminal disclaimer shorten my patent&#8217;s term?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>It can. The disclaimer makes the later patent expire on the same date as the reference patent. If your patent would otherwise have lasted longer, you give up that extra time, and you may also forfeit patent term adjustment you earned for USPTO delay.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"t2\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">What is the difference between statutory and nonstatutory double patenting?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Statutory double patenting under 35 U.S.C. 101 means two patents claim the identical invention and cannot be cured by a disclaimer. Nonstatutory (obviousness-type) double patenting means the later claims are an obvious variant of an earlier commonly-owned patent, and that rejection can be overcome with a terminal disclaimer.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"t3\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">Can I file a terminal disclaimer over someone else&#8217;s patent?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>No. A terminal disclaimer only works against a patent that is commonly owned with your application (or covered by a qualifying joint research agreement). You cannot disclaim over a third party&#8217;s unrelated patent.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"t4\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">Did the USPTO change the terminal disclaimer rules in 2024?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>It tried. A May 2024 proposed rule would have made disclaimer-linked patents unenforceable if any tied claim was later invalidated, but the USPTO withdrew that proposal on December 4, 2024. Current practice is unchanged, with only the long-standing common-ownership enforceability condition in place.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"t5\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">Can a terminal disclaimer be undone after it is recorded?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Rarely. The USPTO will withdraw a recorded disclaimer only in narrow situations, so you should treat the decision to file as effectively permanent and weigh the term and ownership consequences before signing.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>A terminal disclaimer is the fastest way to clear a double patenting rejection, but it costs you patent term and locks your patents together. Here&#8217;s how to decide.<\/p>\n","protected":false},"author":2,"featured_media":1488,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[58],"tags":[281,63,31,282,80],"class_list":["post-1479","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-patent","tag-double-patenting","tag-patent-prosecution","tag-patent-strategy","tag-terminal-disclaimer","tag-uspto"],"_links":{"self":[{"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/posts\/1479","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/comments?post=1479"}],"version-history":[{"count":1,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/posts\/1479\/revisions"}],"predecessor-version":[{"id":1487,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/posts\/1479\/revisions\/1487"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/media\/1488"}],"wp:attachment":[{"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/media?parent=1479"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/categories?post=1479"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.perspireip.com\/blog\/wp-json\/wp\/v2\/tags?post=1479"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}