Shares in PartyGaming jumped after the online gambling group announced that it is to merge with its Austrian rival bwin.The merger will create the world's largest listed online gaming group and would have, PartyGaming. The two companies combined would have turned over about €682m in 2009, it said.Following the merger, PartyGaming shareholders will own about 48.36% of the group with bwin shareholders owning the rest.'This is a transformational opportunity for both our companies to create the world's largest listed online gaming business,' said PartyGaming chief executive Jim Ryan. 'With market-leading positions in poker, sports betting, casino and games (in particular bingo), the enlarged group will have a winning formula to exploit the growing online gaming market, supported by a strong balance sheet, significant cashflow generation and a highly experienced management team.'Bwin's co-chief executive Norbert Teufelberger said: 'This merger of equals makes great strategic, operational and financial sense: we will be in pole position to capitalise on the wealth of opportunities that will flow from the continued evolution and expansion of the global online gaming industry.'Ryan and Teufelberger will be co-chief executives of the new company.