An expected settlement between the U.S. Justice Department and Wachovia Bank over lax anti-money laundering policies is highlighting the compliance risks of doing business with Mexican currency exchange companies. The Charlotte, NC-based bank encountered problems with the companies, known as casas de cambio, in May 2007, after U.S. authorities froze nearly $11 million in accounts held by Mexico-based Casa de Cambio Puebla. Mexican investigators accused the exchange house of helping drug traffickers launder narcotics proceeds through the bank. In February, Wachovia disclosed that it was cooperating with a U.S. investigation into its correspondent accounts with at least two casas de...