(Recasts with agreement to sell stake to GIC)
By Tatiana Bautzer and Guillermo Parra-Bernal
SAO PAULO, Nov 29 (Reuters) - Grupo BTG Pactual SA has agreed to sell its 12 percent stake in Rede D'Or São Luiz SA, Brazil's largest hospital chain, to Singapore's sovereign wealth fund GIC Pte Ltd for almost 2.5 billion reais ($633 million), a source directly involved in the deal said on Sunday.
An announcement could take place early on Monday, said the source, who requested anonymity in order to speak freely about the deal.
Executives at the São Paulo-based bank had been negotiating exiting Rede D'Or since August, although the arrest last week of BTG Pactual's chairman, André Esteves, sped up talks, two other sources said.
Esteves was arrested as part of "Operation Car Wash," a probe into links between ruling coalition politicians and company executives who allegedly traded contracts at state firms for bribes and campaign donations.
He was detained on suspicion of obstructing a bribery investigation centered on Brazil's state-controlled oil and gas company Petrobras, an allegation his lawyer, Antonio Carlos de Almeida Castro, has denied.
GIC paid 3.3 billion reais for a 16 percent stake of Rede D'Or in May. The other partners in Rede D'Or are Brazil's Moll family, which founded Rede D'Or in 1977, and Carlyle Group LP.
Carlyle bought a 4 percent stake in Rede D'Or from BTG in April, as well as a 4 percent stake from the Moll family. BTG had been discussing since August a divestment of another 4 percent in Rede D'Or with Carlyle, the two sources said.
According to one of these two sources, the Molls showed no interest in increasing their stake, and GIC recently emerged as the preferred candidate.
BTG Pactual declined comment, as did representatives for Carlyle and GIC. Media officials for the billionaire Moll family could not be reached for comment.
The Molls and BTG Pactual became partners at the end of 2010.
Bloomberg News reported on Sunday, citing a person with knowledge of the matter, that partners at BTG Pactual are in talks to buy Esteves' 28.8 percent controlling stake in the bank after his arrest.
$1 = 3.8446 Brazilian reais Editing by Leslie Adler