UPDATE 1-Turkish Airlines buys 3 more Airbus planes
* Turkish Airlines decides to exercise option
* Purchase is part of order of up to 105 planes
ISTANBUL, Oct 30 (Reuters) - Flag carrier Turkish Airlines (THYAO.IS) said on Friday it will exercise the option to buy three Airbus A330 planes, part of its ambitious fleet-expansion plans to gain market share in Europe.
Europe's fourth-biggest airline by passenger numbers will take delivery of the planes in 2012, according to a filing issued to the stock exchange.
Turkish Airlines announced in October 2008 that it would buy up to 105 planes from Airbus EAD.PA and Boeing (B.N), worth about $6 billion at list prices.
The planes, to be procured between 2010 and 2012, would nearly triple the state-run carrier's fleet and help it grab market share from European peers Lufthansa and Air France, analysts have said.
The order includes options for 30 planes, the Istanbul-based airline said previously.
Turkish Airlines shares fell 3.21 percent to 4.22 lira, compared with the blue-chip index's 3.52 percent decline. (Writing by Ayla Jean Yackley; Editing by David Cowell)