Bono is set to cash in for up to $500 million on the sale of smartphone company Palm, which has been put on the block. Goldman Sachs are said to be handling the sale.

Bono's private equity company, Elevation Partners, is a 41 percent shareholder in Palm.

Shares in the company have jumped 32 percent to $5.16 in the past week and closed at over $6 yesterday. Palm is said to have already attracted two companies interested in buying the company. It was recently valued at $1.6 billion but will sell for far less than that, experts say.

Rival phone makers HTC and Lenovo are said to have already bid for Palm, which recently tried to launch a comeback with the launch of the Pre and Pixi range of high-end smartphones based on the WebOS operating system.

The smartphones were widely praised by critics but failed to take off with consumers. Palm has undergone 11 straight losing quarters.

“Palm still has quite a good brand in the US market and some strong technology,” Frank He, an analyst with BOC International Holdings told Bloomberg News.

“You can do something with it. The share have gone down a lot and the company may become attractive to anyone looking for a turnaround play.”

Both Palm and Goldman Sachs have declined to comment on the reports.

Palm is currently ranked sixth in the US smart phone market, behind rivals such as Research in Motion, makers of the BlackBerry, and Apple.

Elevation bought a 25 percent stake in the company for $325m in 2007 and put in Jonathan Rubinstein, a former head of Apple’s iPhone division, as chairman.