André Esteves, the billionaire chief executive of the Brazilian investment bank BTG Pactual, is under investigation for trading undertaken in his personal account in Europe in 2007, according to the prospectus for the bank’s initial public offering published this month.

Esteves, whose stake in BTG Pactual could be valued at more than $3.5bn in next week's IPO, is the "subject of an ongoing civil, non-criminal investigation in Europe in connection with certain trades in the securities of a European market issuer made by him in his personal capacity in 2007", according to the prospectus.