Patents that remain pending or in prosecution for a long time to the tune of several years or a decade or more are called submarine patents.
We considered patents filed between 1980-2010 that were in prosecution for more than 10 years. There are 7400 Submarine patents out of which 5745 are still active.
Total US Submarine Patents (1980-2010)
![](https://insights.greyb.com/wp-content/uploads/2021/06/US-submarine-patents.jpg)
Active US Submarine Patents (1980-2010)
![](https://insights.greyb.com/wp-content/uploads/2021/06/count-of-active-us-submarine-patent-1024x591.png)