Bradesco's offer of 17.8bn reais (US$5.2bn) was well above the forecast US$4bn and exceeded last week's bid from Spain's Santander.
The US$15bn deficit for the first half of 2015 was 15% lower than that recorded in the same period of last year.
The federal government has also slashed its key fiscal target - the so-called primary surplus target - this year. It is now aiming for 0.15% of GDP, or 8.75bn reais, compared with 1.1% of GDP previously.
Formally indicted in the corruption scandal, Andrade Gutierrez CEO and billionaire Otávio de Azevedo also chairs the telecoms arm of the Gutierrez group, AG Telecom, and is one of the major shareholders of Rio-based operator Oi.
If elected president, could Daniel Scioli execute a series of infrastructure initiatives he has promised for Corrientes province?