Motorola Mobility Holdings Inc
It did not explain why.
The announcement came two days after the handset maker agreed to be bought by Google Inc
Hambrecht, who was not immediately available for comment, joined the board of Motorola Inc in 2008 and became a director of Motorola Mobility when that company was split off from Motorola Inc in January this year.
Hambrecht's addition to Motorola Inc's board in 2008 was part of a settlement agreement to end a proxy battle between Motorola and activist investor Carl Icahn, who had nominated Hambrecht to the board.
(Reporting by Sinead Carew; editing by Gerald E. McCormick)