UK staff hit Twitter jackpot in sell-off: Dozens in line for huge payouts Britain is social media website Twitter's biggest market after the US Senior employees in London could make sums well into six figures Investors were asking for 30 times number of shares that were on offer Actor Patrick Stewart and other Twitter users rang opening NYSE bell Here we go: Veteran British actor Patrick Stewart and other Twitter users rang the opening bell at the New York Stock Exchange Dozens of Twitter's British staff were in line for a huge payout yesterday as shares in the company soared to almost double their original price on the first day of trading in New York. Britain is the social media website's biggest market after the US and a clutch of senior employees in London could make sums well into six figures thanks to owning shares in the company. They include Bruce Daisley, the UK general manager. With investors asking for 30 times the number of shares that were on offer, demand was always expected to be strong when veteran British actor Patrick Stewart and other Twitter users rang the opening bell at the New York Stock Exchange. In a trading frenzy that recalled the days of the dotcom bubble, the site added billions of pounds to its value in hours. Anxious to avoid a repetition of the Facebook stock market launch, in which lukewarm investors proved it had been over-valued at £65billion, Twitter bosses valued the site at a relatively modest £11billion. With management, including co-founder Jack Dorsey, on the trading floor to watch their fortunes surge, shares opened at around £28 - 75 per cent above Twitter's initial offer of £16. All smiles: Twitter CEO Dick Costolo (right) celebrates the Twitter IPO with Twitter founders Jack Dorsey (left), Biz Stone (second left) and Evan Williams on the floor of the New York Stock Exchange Within two hours, they were even higher, before settling back to close at £28. Mr Dorsey - who critics have accused of cynically downplaying the role of others in setting up Twitter - saw the value of his shares rise to at least £686million during the day. The flurry of buying and selling pushed a company that has never made a profit in its seven-year existence to be valued around the same as long-established giants such as KFC and the Pizza Hut owner Yum! Brands. Twitter is offering 70million shares for sale but few ordinary investors will get hold of them initially. Most are divided up between big investors such as mutual funds and the banks who set up the flotation. Advertising experts believe Twitter can exploit its huge base of 232million active users - including world leaders and celebrities - by putting adverts into its 140-character messages. In the money: A clutch of senior Twitter employees in London could make sums well into six figures thanks to owning shares in the company. They include Bruce Daisley (pictured), the UK general manager But financial analysts have sounded a note of caution. Some wonder whether the enthusiasm will last when the hype dies down and investors ask how can Twitter possibly justify its share price without a huge rise in earnings. Experts point out that Twitter's entire business model is based on advertising that it hopes one day to receive, not adverts that it already attracts. As one analyst put it: "It's all about turning those tweets into dollars now." Tomas Freyman, valuations director at finance house BDO, said: "We're in bubble territory." Other social media sites have dwindled in popularity after owners tried to commercialise them. Up and up: In a trading frenzy that recalled the days of the dotcom bubble, the site added billions of pounds to its value in hours Sceptics say Twitter has a particularly hard task making money, wondering how advertising can be squeezed into its short text messages without ruining its appeal. 'It's all about turning those tweets into dollars now' Analyst Twitter, founded in 2006 by a small group of internet entrepreneurs in San Francisco, has another pressing problem. While more than three quarters of its users are outside the US, only a quarter of its revenue comes from there. A Saudi Arabian royal, Prince Al-Waleed bin Talal, invested £187million in Twitter 2011 and has seen his stake soar to £479million.