(Reuters) - Ancestry.com ACOM.O shares fell 18 percent on Monday after U.S. network NBC decided not to renew the company's TV show for a fourth season.
Ancestry.com sponsors the American version of the popular British series Who Do You Think You Are.
The show, based on the idea of tracing celebrities' family history through Ancestry.com's databases, has been considered a major driver of new subscriber additions for the website.
The company runs an online website which helps subscribers track family history. It had about 1.7 million subscribers at end of 2011.
Who Do You Think You Are, which has featured celebrities such as Steve Buscemi, Martin Sheen, Marisa Tomei and Lionel Richie, first premiered in 2010 in the U.S.
On Sunday, Ancestry.com said NBC will not renew the show for a fourth season.
The company's shares were down 16 percent at $22.11 in early trading on the Nasdaq.
(Reporting by Himank Sharma in Bangalore; Editing by Sreejiraj Eluvangal)