UniCredit likely to choose talks partner for Pioneer on Friday-source

* CVC (Taiwan OTC: 4744.TWO - news) consortium is frontrunner - source

* Pioneer valued at over 2 bln euros-sources

* UniCredit (Milan: UCG.MI - news) declines to comment (Adds background, shares)

MILAN, Sept 12 (Reuters) - Italian lender Unicredit is likely to choose a partner for exclusive talks to buy a stake of up to 50 percent in its asset management division Pioneer on Friday, a source familiar with the matter said.

Italy's biggest bank by assets has received bids for Pioneer from Spain's Banco Santander (Amsterdam: SANT.AS - news) , U.S. fund Advent and a consortium comprising CVC Capital Partners and Singapore sovereign fund GIC, people with knowledge of the matter have said.

"The CVC consortium is frontrunner," the source said on Friday. UniCredit declined to comment.

Like other Italian and European lenders, UniCredit has been shedding assets, cutting jobs and closing branches to shore up its capital base ahead of a health check of euro zone banks whose outcome is set to be made public next month.

The bids on UniCredit's table are for a stake of up to 50 percent in Pioneer, which as a whole is worth around 2 billion euros ($2.6 billion), sources have said.

A report in Italian daily MF on Friday said that, ahead of a decision on exclusivity talks, the three bidders had improved their offers, which had initially valued Pioneer at between 2 billion euros and 2.5 billion.

UniCredit had in 2011 mulled the sale of Pioneer but dropped the idea after failing to conclude a tie-up with Eurizon, the fund management arm of domestic rival Intesa Sanpaolo.

In August UniCredit CEO Federico Ghizzoni said Pioneer was a strategic asset and the idea was to keep a "strong stake". (1 US dollar = 0.7738 euro) (Reporting by Stephen Jewkes; Editing by Silvia Aloisi and David Holmes)