NEW YORK – American authorities on Tuesday cited “astonishing” dysfunction at the British bank HSBC and said that it had helped Mexican drug traffickers, Iran, Libya and others under U.S. suspicion or sanction to move money around the world.

HSBC agreed to pay $1.9 billion, the largest penalty ever imposed on a bank.

The U.S. stopped short of charging executives, citing the bank’s immediate, full cooperation and the damage that an assault on the company might cause on economies and people, including thousands who would lose jobs if the bank collapsed.