EXCLUSIVE-UPDATE 1-Macquarie is lead bidder for Robeco -sources

* Deal could fetch up to $3 billion euros-source

* Orix still in the running-sources

(Adds background, Rabobank comment)

NEW YORK, Dec 19 (Reuters) - Australia's Macquarie Group Ltd has emerged as the lead bidder to buy Robeco, the asset management arm of Dutch bank Rabobank NV, four people familiar with the matter said this week. The deal could fetch around 3 billion euros ($3.96 billion), one of the sources said.

The Netherlands' largest retail bank also received a bid from Japanese financial services firm Orix Corp for all of Robeco.

Orix is also still in the running, the sources said.

As of Sept. 30, Robeco's assets under management totaled 188 billion euros ($248 billion).

Rabobank, which is looking to shore up its capital position, had told prospective buyers that it wants to sell the business as a whole, according to the sources, who declined to be identified because the deal talks were confidential.

A Rabobank spokesman confirmed that the firm is considering "all strategic options regarding Robeco," but declined to elaborate.

A spokeswomen for Macquarie declined to comment. A representative at Orix did not respond to requests for comment. (1 euro = $1.32)

(Reporting By Jessica Toonkel; Editing by Gerald E. McCormick and Alden Bentley)