'HSBC Holdings Plc (HSBA)’s Mexican branches had become so well-known to drug traffickers as the place to launder proceeds from illicit sales that cartels began using special boxes to speed transactions, U.S. prosecutors said.

From 2006 to 2010, the Sinaloa cartel in Mexico and the Norte del Valle Cartel in Columbia moved more than $881 million in proceeds through HSBC’s U.S. unit, said Lanny Breuer, assistant attorney general for the U.S. Justice Department’s criminal division. Breuer, along with U.S. Attorney Lorretta Lynch in Brooklyn, New York, announced yesterday the bank had agreed to pay at least $1.9 billion to settle money laundering probes.

“These traffickers didn’t have to try very hard,” Breuer said at a press conference in Brooklyn. “They would sometimes deposit hundreds of thousands of dollars in cash in a single day into a single account using boxes designed to fit the precise dimension of the tellers’ windows in HSBC’s Mexico branches.”'

Read more: HSBC Mexican Branches Said to Be Drug Traffickers’ Favorites