Trading in Apple  options have surged after investor Carl Icahn revealed via Twitter  a large stake in the tech company, which he believes to be undervalued. Photograph: Chip East/Reuters

Activist investor Carl Icahn said he has amassed a “large position” in Apple and believes the stock could be worth as much as $700 a share if chief ex(...)

BlackBerry shares have increased 14 per cent, fuelled by takeover speculation. Photo: Reuters

BlackBerry shares rose 14 per cent yesterday, fuelled by takeover speculation and news that AT&T will start selling the new BlackBerry Z10 (...)