"I would like to encourage you to collaborate with the CVM, because (those involved) will certainly be identified," CVM chief Joao Pedro Barroso do Nascimento told a congressional committee.

Americanas last week admitted to a large-scale accounting fraud with current top managers slamming former executive, banks and auditors for their alleged involvement in "fraudulently altered" financial statements.

Americanas filed for bankruptcy protection in January after uncovering an over $4 billion accounting scandal. The report issued on Tuesday accused ex-CEO Miguel Gutierrez and half a dozen other former executives and employees of committing fraud.

Federal police, as well as CVM and other institutions, are investigating the case.

(Reporting by Patricia Vilas Boas; Writing by Carolina Pulice; Editing by Sarah Morland and Aurora Ellis)