UPDATE 2-Rabobank weighs bids for asset manager Robeco

* Advent/CVC, AMG/Permira and Japan's Orix bid -sources

* AMG/Permira plan to split up Robeco -sources

* Robeco could fetch more than 2 bln euros -sources

(Adds details on Robeco sale, Maquarie, Robeco business)

By Simon Meads and Jessica Toonkel LONDON/NEW YORK, Oct 10 (Reuters) - Dutch bank Rabobank

is weighing three offers for its asset management arm Robeco, facing a choice between bids to split the 2 billion euro-plus ($2.6 billion) business or sell it in one piece, people familiar with the situation said.

The Netherlands' largest retail bank received bids from a private equity consortium of Advent International and CVC , and from Japanese financial services group Orix

for the asset management unit.

It received a third bid from Boston-based asset manager AMG Inc , which in partnership with buyout firm Permira

wants to split up the business that spans Europe and the United States, the people said.

Rabobank is in talks with various bidders and is evaluating the offers, one of the people said.

The cooperative bank, which is returning to its roots lending to Dutch farmers, put Robeco up for sale early this year after it lost its triple-A credit rating from Standard & Poor's and sought to prepare for stricter capital rules for European banks.

Australian bank Macquarie remains interested in the business but it is unclear whether it made a formal bid, some of the people said.

Initially valued at less than 2 billion euros, price expectations have soared, with one source saying the firm could fetch as much as 3 billion euros.

The high price prompted some of the bidders to team up to buy Robeco in what remains a challenging market for mergers and acquisitions in Europe, especially for private equity players that are struggling to secure finance for large deals.

The length of time taken to get to this stage in the bidding has frustrated some who felt rushed into preparing throughout August for bids in mid-September.

"While Deutsche Bank ruined Christmas, Robeco ruined summer vacations," said a person close to one of the bidders.

Deutsche Bank attempted to sell its asset management business before halting the sale plans earlier this year.

Rabobank has told prospective buyers that it wants to sell the business whole, people familiar with the process have said.

However AMG's bid with Permira wants to split the company, with the asset manager taking on Robeco's U.S. divisions, such as Chicago-based Harbor Capital Advisors and Robeco Investment Management, with offices in New York as Boston, two of the people said.

Permira would then pick up the group's European assets such as Corestone and SAM Sustainable Asset Management in Switzerland and Robeco Institutional Asset Management based in the Netherlands' second city Rotterdam.

While viewed as a better business than rival Dexia Asset Management, which was also put up for sale earlier this year by the Franco-Belgian bank Dexia, earnings at some of Robeco's divisions are volatile and that is provoking concerns among some of the prospective buyers, one of the sources said.

Robeco had 186 billion euros of assets under management at the end of July, more than twice the size of Dexia Asset Management.

Rabobank and Robeco declined to comment. The named bidders also declined to comment or were unavailable for comment.

(Additional reporting by Sara Webb in Amsterdam; Editing by Douwe Miedema and Erica Billingham)

((simon.meads@thomsonreuters.com)(+44 20 7542 9969)(Reuters Messaging: simon.meads.thomsonreuters.com@reuters.net))