Tellabs (TLAB) was down 6.7% in preopen Instinet trading after it posted a third-quarter loss of 12 cents per share including one-time items. A year ago, the telecommunications equipment maker posted a 45-cent profit.
Analysts expected a profit of 5 cents per share, Thomson Financial/First Call reported.
Tellabs declined to provide fourth-quarter estimates, citing an inability to forecast business trends. In recent months the company has cut expenses and jobs to cope with a falloff in technology spending.
"We are encouraged to see greater stability in our U.S. customers' recent order patterns,'' Richard Notebaert, the company's president and CEO said in a statement. He said more than 10 percent of third-quarter sales were generated by new products, including a series of optical switches that help connect voice and data traffic.