Submarine patents are patents which stay hidden from the public long after the initial registration. As such sub-marine patents can be described as patents of which the publication are delayed for a specific reason and for an extended period which can be several years. Submarine patents were possible in the USA in the past, but fortunately are no longer valid. Before 2000 and more specifically, the month of November, a submarine patent could stay hidden for a long time. If a person didn’t publish the patent, it would remain secret until full granted.

Patent pirates would often make use of the submarine patents to surprise the market and institute lawsuits for infringement based on the sub-marine patent date of filing. When the United States signed the World Trade Organisation (WTO) TRIPS agreement the term of the patent became measured from the filing or priority date and no longer the date of issuance.

There may, however, be a few patents which were filed prior to the date of the USA signing of the TRIPS agreement which was done in 1995. These submarine patents can thus still be issued. In the past it was possible to delay the issuance of a patent with as many as four decades after the application. This would make it possible to modify the claims to ensure that it could resemble the more modern standards.

Today, however, the main proportion of USA patent applications is published within the window of 18 months of the initial application date. If an applicant indicates that he has no intention of filing a patent outside the country’s borders for the same, he will still be able to keep the application hidden. With submarine patents thus still a strong possibility in the USA, it is best to get legal advice before filing a patent application in the USA.