UPDATE 1-Qatar's CBQ sees Turkish bank deal by March

* CBQ aims to complete Alternatifbank deal by end-March

* Turkish bank current market value at $570 mln (Adds detail, context)

DUBAI Jan 17 (Reuters) - Commercial Bank of Qatar (CBQ) expects to complete the purchase of a 75 percent stake in Turkey's Alternatifbank by the end of March, it said on Thursday.

The Gulf state's third-largest bank by market value began talks in December with Anadolu Holding to acquire the stake, the latest example of Gulf lenders looking outside their home market for acquisition targets.

Alternatifbank has a current market value of $570 million, meaning the stake would cost the Qatari bank $427.5 million at market price.

The London stock exchange statement follows comments from Anadolu Holding Chairman Tuncay Ozilhan earlier this week, which said a deal should be completed by March 15.

CBQ's statement was issued to the London stock exchange, where it has depositary receipts listed.

Recent Qatari banks' strong interest in Turkey is likely to stem from the desire to diversify out of their home country's narrow economy, coupled with the lack of potential acquisitions in the Gulf region, Fitch Ratings said in a Jan 14 note.

Qatar National Bank, the Gulf state's largest lender, is interested in expanding into Turkey through acquisitions, its chief financial officer said on Wednesday, but had no firm targets currently.

It bid for Denizbank bank last year but lost out to Russia's Sberbank in the process.

Alternatifbank shares rose 2.5 percent on the Istanbul stock exchange at 1345 GMT. The shares have more than doubled in the last three months following reports of the potential stake buy. (Reporting by David French; Editing by Dinesh Nair)