By Simon Zekaria Of DOW JONES NEWSWIRES LONDON (Dow Jones)--Shares in PartyGaming PLC (PRTY.LN) soared Thursday after the U.K.-listed gambling group said it plans to merge with Vienna-listed peer bwin Interactive Entertainment AG (BWIN.VI), one of Europe's largest sports book operators. At 1019 GMT, shares in PartyGaming, the world's biggest listed online gaming group by market capitalization, rose 22% to 313 pence, valuing the company at GBP1.28 billion. The deal for the tie-up, owned by 48.36% and 51.64% by PartyGaming and Bwin shareholders respectively, will create the world's largest listed online gambling business, the group said. The merged entity, which will be listed on the London Stock Exchange, will have net gaming revenue of EUR682 million and earnings before interest, taxes and amortization of EUR196 million, before synergies, it said. The tie-up is expected to be "significantly earnings enhancing" for both companies pre-amortization. Jim Ryan, Chief Executive of PartyGaming and Norbert Teufelberger, Co-CEO of bwin, will be Co-CEOs of the merged group. Irrevocable undertakings in support of the merger have been received from shareholders currently holding 28.5% and 14.4% of PartyGaming and bwin's existing issued share capital respectively, the group said. -By Simon Zekaria, Dow Jones Newswires; +44 207 842-9410; simon.zekaria@dowjones.com (END) Dow Jones Newswires July 29, 2010 06:27 ET (10:27 GMT)