Patent pending

• It tells the public that an application has been filed¹. The USPTO glossary adds that it warns that a patent may issue that would cover the item, and that copiers should be careful because they might infringe if the patent issues⁸.
• It gives no protection of its own. The USPTO says patent protection does not start until actually granted¹.
• A provisional application permits use of the notice. The USPTO describes this as authorized use of "Patent Pending" for 12 months, and says the 12-month pendency period cannot be extended³.
• A provisional application automatically becomes abandoned when its pendency period expires, so a nonprovisional application must be filed within that period to benefit from it, unless the benefit is restored under 37 CFR 1.78, in which case the nonprovisional may be filed within 14 months³.
• Once the patent issues, the owner will stop using the phrase and start using a phrase such as "covered by U.S. Patent Number" followed by the number⁸.

See Provisional patent application for how a provisional filing works.

In the US, infringement of a patent requires an act during the term of the patent (35 U.S.C. 271(a))⁹, and the term begins on the date the patent issues (35 U.S.C. 154(a)(2))². A pending application alone therefore does not support an infringement claim.

The exception is provisional rights. A patent includes the right to obtain a reasonable royalty from a person who, between publication of the application and issue of the patent, makes, uses, offers for sale, sells or imports the invention as claimed in the published application². All of these conditions apply²:

1. The application was publishedThe period starts on the date of publication of the application under 35 U.S.C. 122(b), or on the date of international publication for an international application designating the United States, and ends when the patent issues². If the international application was published in a language other than English, the right starts only on the date the USPTO receives an English translation of the publication (35 U.S.C. 154(d)(4)(A))².
2. The defendant had actual noticeThe person must have had actual notice of the published application. If the international application was published in a language other than English, the person must have had an English translation².
3. The claims are substantially identicalThe invention as claimed in the patent must be substantially identical to the invention as claimed in the published application².
4. The suit is brought in timeThe action must be brought not later than 6 years after the patent is issued².

The remedy is a reasonable royalty. The increased damages available under 35 U.S.C. 284 do not apply to provisional rights¹⁰.

Section 292(a) covers anyone who marks upon, affixes to or uses in advertising, in connection with any article, the words "patent applied for" or "patent pending", or any word importing that an application has been made, when no application has been made or, if made, is not pending, for the purpose of deceiving the public⁶.

• The penalty is a fine of not more than $500 for every such offense, and only the United States may sue for it⁶.
• A person who has suffered a competitive injury as a result of a violation may file a civil action for damages adequate to compensate for the injury (35 U.S.C. 292(b))⁶.
• The statute requires the purpose of deceiving the public. The USPTO's summary is that false use of these phrases or their equivalent is prohibited and subject to a fine, and that those suffering competitive injury may seek damages¹.

The marking rules above are US law. This page does not cover marking rules elsewhere. Protection linked to publication of an application is also found in Europe and China.