ISIS netted $500mn-$1bn when it took Mosul last year
A Senior US official has confirmed that ISIS looted some $429 million in cash plus 'a large quantity of gold bullion' from Mosul's central bank branch when the city fell last June. Daniel Glaser, the US Treasury's assistant secretary for terror financing, also stated that the terror-group's oil revenues run at about $40mn per month, and that it fighters are paid $1000 per month.
“ISIS netted between $500 million and $1 billion in cash when it took over Iraq’s second largest city in 2014, a top Obama administration official said Thursday. Daniel Glaser, the U.S. Treasury’s assistant secretary for terror financing, told participants at the Aspen Security Forum that when ISIS swept through the city of Mosul in northern Iraq, it took the reserves of over 90 banks, estimated to be between $500 million and $1 billion.”

Source: Mosul Takeover Netted ISIS Up to $1B in Cash, US Official Says | Military.com