The computer maker's shares surged on rumors that billionaire activist investor Carl Icahn was buying in. Hewlett-Packard (HPQ) declined to comment on the rumor, which spread Mon. on Twitter. HP shares have been falling for about 30 months after a series of missteps and diminishing prospects for its printer and PC businesses. It took another hit last month after the company said it would take a $9 bil asset impairment charge concerning its acquisition of Autonomy. Separately, DigiTimes said HP's notebook shipments climbed slightly in Nov. Shares rose 2.61%.