The US will likely suffer the loss of its triple-A credit rating from another major agency by the end of this year due to concerns over the deficit, Bank of America Merrill Lynch forecasts.

The trigger would be a likely failure by Congress to agree on a credible long-term plan to cut the US deficit, the bank said in a research note published on Friday.

A second downgrade — either from Moody’s or Fitch — would follow Standard & Poor’s downgrade in August on concerns about the government’s budget deficit and rising debt.

If a majority of a 12-member committee fails to agree on a plan before Nov. 23, $1.2 trillion in automatic spending cuts will be triggered, beginning in 2013.