palmOne ( PLMO) is losing its top executive. CEO Todd Bradley has resigned, the handheld computer company announced Monday. Bradley's resignation is effective Feb. 25, which is the end of palmOne's fiscal quarter. He will be replaced on an interim basis by Ed Colligan, palmOne president, while the company searches for a permanent successor. "I've accomplished what I set out to do," Bradley said in a statement. "I feel the time is right for me to move on to another challenge." Investors apparently disagreed, selling off palmOne's stock in the after-hours market. In recent trading, the company's shares were down $2.29, or 8.6%, to $24.30. The company's stock closed regular trading on Monday off $1.22, or 4.4%, to $26.59. Bradley will remain with the Milpitas, Calif.-based company until the end of its fiscal year in May to help with the transition to a new CEO. His departure is only the latest top-management change at palmOne's executive suite in the last year. Last week the company announced that Angel Mendez, its head of global operations, had resigned to join Cisco Systems as its senior vice president in charge of worldwide manufacturing. Last month, the company named Andrew Brown CFO. Brown replaced Judy Brunner, who left in June to join SanDisk ( SNDK). Bradley joined palmOne as its chief operating officer in 2001. The company promoted him to president in 2002 and to CEO in 2003 after it merged with Handspring. He also has served on the company's board of directors since 2002. The company did not say if he would depart its board. palmOne paid Bradley $1.5 million in salary and bonus last year and another $514,433 in restricted stock. It also granted him some 215,052 stock options with an exercise price of $11.20 a share.