(Reuters) - Video-streaming service Netflix Inc
The company's shares slumped 11.6 percent in after-hours trading on Monday.
Netflix, which started in 1997 as a DVD-rental-by-mail firm, forecast adding about 500,000 customers in the United States in the second quarter.
Analysts on average had expected the company to add 586,000 subscribers in the United States, according to research firm FactSet StreetAccount.
The company said it added 2.23 million U.S. subscribers in the first quarter, more than the 1.75 million it had expected would sign up.
(Reporting by Anya George Tharakan in Bengaluru; Editing by Savio D'Souza)