Jan 29 (Reuters) - Neustar Inc, which routes phone calls and manages databases used by North American telecom carriers, forecast a full-year adjusted profit below estimates, sending its shares down 25 percent after market.
Neustar, whose customers include Verizon Communictions Inc , AT&T Inc and cable companies including Comcast Corp, said it expected full-year adjusted net income of between $3.64 and $3.80 per share.
Analysts, on average, expect earnings of $3.82 per share, according to Thomson Reuters I/B/E/S.
Avondale Partners analyst John Bright said uncertainty over the renewal of the company's Number Portability Administration Center (NPAC) contract was the main reason for the disappointing outlook.
The NPAC is the registry that permits consumers and enterprises to maintain their telephone numbers when they change service providers. Neustar serves as the NPAC Administrator for the United States and Canada.
The NPAC contract accounts for about 50 percent of Neustar's revenue and at least half of its profit, Bright said.
Neustar shares were trading at $32.40 after the bell after closing at $43.75 on the New York Stock Exchange. (Reporting by Aditi Shrivastava in Bangalore; Editing by Ted Kerr)