The total number of patents that tech giant Samsung Electronics holds in the U.S. increased by more than fifteen times over the past nine years, according to the company on Thursday.

Samsung’s patents registered at the U.S. patent office stood at 38,809 last year, up from 2,457 in 2007.

In 2015 alone, Samsung obtained 5,072 patents in the nation, the second highest after tech firm IBM. Since 2006, Samsung has been the second most prolific patent filer in the U.S., after Big Blue.

“Samsung has been holding the most number of patents in the U.S. compared to other regions to effectively respond to possible patent conflicts there,” the company said.

The firm’s patents in the U.S. account for 35 percent of its total patents registered around the world, which stands at 110,145.

The patent filings are mostly aimed at protecting technology for the firm’s smartphones, smart TVs, memory chips and System LSI, or non-memory chips.

The Seoul-based tech giant said protecting its next-generation technology is one of the company’s top priorities for future growth.

Samsung has also been trying to bolster its design capacity by filing design patents for smartphones and TVs.

Among the 5,072 patents that Samsung gained in the U.S. last year, 1,342 were those to protect key design elements.

Samsung has a long history of patent disputes with its rivals, as well as global patent trawlers. The most prominent case is the one with U.S.-based smartphone maker Apple.

In 2011, the iPhone maker filed a lawsuit against Samsung, claiming the Korean firm had copied the iPhone’s square, round-corner, icon design. It later filed different suits against the Galaxy smartphone maker for infringing its patents including those for the rounded corners of the iPhone and its slide-to-unlock feature.

Most recently, a Chinese network equipment maker has sued Samsung for violating its patents for communications networks and software to run the fourth-generation networks on 4G mobile devices.

Samsung said it was considering a countersuit against the Chinese firm.

By Kim Young-won(won0102@heraldcorp.com)