FILE PHOTO: A logo of the Brazil's state-run Petrobras oil company is seen in Rio de Janeiro, Brazil March 25, 2019. REUTERS/Sergio Moraes

SAO PAULO (Reuters) - At least three investors left separate groups interested in acquiring a gas network pipeline that will be sold by Brazil’s state-controlled oil company Petroleo Brasileiro SA, three sources with knowledge of the matter said.

Those departures will likely leave a third group, led by France’s Engie SA with Canadian pension fund Caisse de Depot et Placement du Quebec, stronger. The final bids for TAG, as the unit is known, are due on Tuesday.

After the previously reported departure of Australia’s Macquarie Group Ltd from one of the groups, which still includes Brazilian investment firm Itausa Investimentos SA and Singapore sovereign wealth fund GIC, the other two investors that were supporting the bid, sovereign wealth fund Abu Dhabi Investment Authority, known as Adia, and investment manager Wren House Infrastructure, also pulled out.

A second group, led by Mubadala Investment Company and EIG Global Energy Partners, had been in talks with the world’s largest investment firm, BlackRock Inc, but the company gave up.

Wrenhouse, Adia, EIG, Mubadala and Itausa did not immediately comment on the matter. BlackRock, which would have a small stake in TAG, declined to comment.

The weakening of the Itausa Investimentos and Mubadala groups raises the chance of Engie, which was the winner of the first bid round, winning the deal. It is not clear if the three groups will deliver the proposals as it was previously expected.

The sale of TAG is expected to be the largest divestment in Petrobras’ asset sale program. The oil company expects to fetch around $8 billion.

All bids were expected to use a large amount of debt to finance the acquisition, as banks are eager to fund the pipeline, which has an extremely stable cash flow. Still, last-minute changes in the group complicate the financing, one of the sources said.