The British bank has agreed to a $340 million penalty to settle allegations from New York state regulators that the bank was laundering money for their Iranian customers. The Wall Street Journal describes a settlement in their article Bank Settles Iran Money Case. This is one in a long string of settlements for money-laundering.
The accusation by the New York Department of Financial Services is that over the course of a decade the bank hid Iranian involvement for 60,000 wires totaling $250 billion. The basic concept is the wires were withdrawn after initial submission and the identifying information removed from the transaction, then the instructions were resubmitted.
I touched on this in an earlier post.