Navigation technology company TeleNav Inc warned that a contract renegotiation with its largest customer could lead to a fall in revenue, sending its shares down 16 percent in extended trade.

TeleNav said it expects any extended agreement would lead to declines in average revenue per user and significant reductions in total revenue from Sprint Nextel Corp, despite a likely rise in the number of subscribers.

TeleNav got 61 percent of its revenue from Sprint in 2009.

The current contract for TeleNav to provide the Sprint Navigation application runs through 2011, but TeleNav is set to lose its exclusivity on the deal at the end of this year.

The company, which went public in May, also posted better-than-expected fourth-quarter results and forecast current-quarter results above expectations.

Shares of the Sunnyvale, California-based company were trading down $1.41 at $7.50 in post-market trade. They closed at $8.91 Thursday on Nasdaq.

(Reporting by Sayantani Ghosh in Bangalore; Editing by Maju Samuel)