The Islamic State has garnered as much as $1.5 billion in revenue by looting banks and illicit oil proceeds, according to a Treasury Department spokesperson.
“Our most recent estimates that we can provide publicly are between $500 million and $1 billion in seized bank assets, based on 2014 data,” the official said. “Earlier this year, (the Islamic State) made about $40 million in one month from the sale of oil…that equals close to $500 million a year.”
There are other sources of funding for the Islamic State as well. In February, the Pentagon claimed that oil was no longer the main source of funds for the Islamic State, but that it was relying increasingly on foreign contributions to fund its Jihad.