British online gaming group PartyGaming Plc
said on Tuesday it agreed to buy U.S.-based branded gaming firm WPT Enterprises Inc , known as World Poker Tour, for $12.3 million in cash.

PartyGaming said it would also pay a minimum of $3 million over the next three years to World Poker Tour's vendors on an ongoing revenue share related to the assets purchased.

The acquisition is expected to be completed in the fourth quarter of 2009, PartyGaming said in a statement.

In a late evening release on Monday, WPT had said it agreed to sell substantially all of its operating assets other than cash, investments and certain excluded assets to Peerless Media Ltd, a unit of ElectraWorks Ltd, which is owned by PartyGaming.

PartyGaming is WPT's largest customer, accounting for 30 percent of its revenue for the six months ended June 28, WPT said in a regulatory filing.

Last month, PartyGaming had said it was looking for further acquisitions following its purchase of bingo website operator Cashcade for an initial 71.9 million pounds ($118.8 million at that time).

Earlier this month, rival online gaming firm 888 <888.L> said it was close to making an acquisition and expected a deal to be completed soon.

PartyGaming shares were down 0.5 percent at 268.2 pence in volatile trade by 0848 GMT on the London Stock Exchange.

(Reporting by Kumar Alagappan in Bangalore; Editing by Gopakumar Warrier)