US Attorney General Eric Holder says Bank of America has agreed to pay more than $16.6 billion in penalties and consumer relief, which "constitutes the largest civil settlement with a single entity in history".

The agreement was announced in Washington, DC on Thursday morning.

The payout will be the largest in a series of soaring penalties against banks for a range of misconduct, including violating U.S. sanctions and inappropriately marketing mortgage securities. An agreement in principle was reached earlier this month after a phone call between the bank's chief executive, Brian Moynihan, and Attorney General Eric Holder.

The negotiations have been driven by an investigation into securities sold by Merrill Lynch, which the bank agreed to acquire in 2008 at the height of the financial crisis, people familiar with the matter have said.

Bank of America is expected to pay about half the penalty in cash with the rest given as assistance to struggling homeowners.