Chinese cell phone designer China TechFaith Wireless Communication Technology Ltd. said Monday it tripled its fourth-quarter profit, helped by a jump in revenue and a rise in value of derivative securities on its books.

The company earned $3.1 million, or 7 cents per share, up from $824,000, or 2 cents per share, in the same quarter a year before.

The latest quarter included a one-time gain of $1.8 million from the rising value of derivatives tied to a convertible bond sale the company made last year.

Revenue increased 13 percent to $59.8 million.

For all of 2009, China TechFaith earned $6.3 million, or 14 cents per share, down from $8 million, or 18 cents per share, the year before. Full-year revenue climbed 1 percent to $211.1 million from $208.9 million.

For the current quarter, the company projected $60 million to $62 million in revenue.

Shares of China TechFaith fell 21 cents, or 6.4 percent, to $3.05 in aftermarket activity. They earlier added a penny to close at $3.26. The stock has ranged from $1.14 to $3.93 over the past year.