Banco Itaú expects regulatory approval next month for its planned takeover of Bank of America’s BankBoston, a subsidiary of the former FleetBoston. In return, Bank of America will take a 6% stake in Itaú, valued at $2.2 billion. The deal adds $9.7 billion in assets to Itaú’s balance sheet, making it the largest private lender in Brazil. Itaú will also gain BankBoston’s 66 branches and 200,000 clients. Meanwhile, Brazil’s equity markets have erased nearly six months of gains on fears that rising US interest rates will draw investment away from emerging markets.