Brazil’s government-controlled banks have been given the green light to help prop up financial institutions owed money from companies that have made bad bets on the country’s currency amid growing concerns about the level of exposure.

Sadia, a food processor; Votorantim, an industrial conglomerate; and Aracruz, one of the world’s biggest paper and pulp manufacturers, have admitted to heavy losses on currency derivatives after Brazil’s currency, the real, devalued sharply against the US dollar in the past few months after appreciating steadily for almost four years.