Shareholders in Belfast software company APiON, who received $239 million worth of Phone.com shares when they sold their company to the US giant, have seen the value of those shares rise by more than 20 per cent in the space of two days.

The phenomenal appreciation in the Phone.com share price, which continues a trend going back to the beginning of August, means that the 1.3 million shares issued to the APiON shareholders were worth as much as $290 million at Phone.com's "high" on the NASDAQ yesterday before easing back to be worth just more than $280 million at the close.

The Phone.com shares were issued to the APiON shareholders at just more than $183 each, but these jumped to $205 by the close of trading on Monday and rose as high as $223 on the NASDAQ before falling back to a trading range around $216.

The biggest shareholder in APiON was Dublin computer entrepreneur Mr Gilbert Little, whose stake in Phone.com jumped in value from $60 million to $70 million yesterday.

Enterprise Ireland's stake in Phone.com has risen in value from $20 million to $23.6 million, while other APiON shareholders who have seen their paper fortunes soar in value include APiON managing director Mr Denis Murphy and five other members of the software group's management, Mr Larry Quinn, Mr Joe Cunningham, Mr Paul Tierney, Mr Mehren Miramahdi and Mr David Megan.

Phone.com shares have more than trebled in value in little more than 10 weeks. At the beginning of August they were trading at just over $60 but have risen constantly since then to the $183 at which the 1.3 million shares were issued to the APiON shareholders and the $223 at yesterday's high on NASDAQ.

That rise yesterday came against the background of a generally weaker market and following an announcement that Phone.com has linked up with computer giant Oracle to enable Internet and intranet access for wireless handsets.