William R. Hambrecht, the San Francisco investment banker, resigned as a director of Motorola Mobility, 11 days after voting to approve its sale to Google.

Hambrecht, 76, said he was "delighted with the transaction we entered into with Google," which plans to acquire the Libertyville, Il.-based smartphone and electronics manufacturer for $12.5 billion.

Hambrecht was one of three nominees elected in 2008 after investor Carl Icahn first invested in the former Motorola Inc. and agitated for better performance. That helped precipitate the resignation of then-CEO Ed Zander and the ultimate split of the company into Motorola Mobility and Motorola Solutions.

Hambrecht is now CEO of WR Hambrecht & Co., an investment bank specializing in "Dutch auctions" that reduce costs to companies that seek to go public. He has long been a shareholder activist.

He's also no stranger to deals: the Princeton graduate long ago sold his first investment bank, Hambrecht & Quist, to the predecessor company of what is now JPMorgan Chase & Co. For years, the Hambrecht & Quist Technology Conference each spring was the premier showcase for technology companies and investors in Silicon Valley.

One year, Steve Jobs, now CEO of Apple, demonstrated to investors the first computers designed by his NeXT Inc., the company he set up after being fired from Apple by then-CEO John Sculley.

Another Icahn nominee to the Motorola Mobility board, Daniel Ninivaggi, is President of Icahn Enterprises. Thr third nominee, Keith Meister, left Icahn last year to establish his own investment company, Convex Management.