Just been listening to opinions about this on the radio -- the New York banking regulator is a new regulation body looking to make a big splash. They chose a non-American bank to start with and an 'easy target' at that. Standard Chartered state that only a few million dollars went through this as opposed to the 160 billion that the regulator is claiming. There's a lot of politics involved here.
There have also been a number of American banks in scandals recently (including one fined $400 million for Mexican drug cartel laundering same as HSBC was fined for) but strangely the American regulators don't make as much of a noise about those.
Generally speaking -- storm in a teacup. If I had gone with my initial thought to buy Standard Chartered shares this mid-morning after the slump, I'd be almost 10% in profit already. I still might buy some tomorrow.