ISIS brings in about $40 million a month in revenue from oil sales, according to remarks made by Acting Treasury Undersecretary Adam Szubin in London on the same day the U.S. military announced it had killed ISIS' finance minister in an airstrike in Iraq late last month.
According to Adam Szubin, ISIS has earned $500 million from oil sales so far, as well as between $500 million and $1 billion from Iraqi and Syrian bank lootings, while it "extorted many millions more from the populations under its control."
ISIS "presents a challenging financial target," Szubin said in the prepared remarks. "Unlike many other terrorist groups, ISIL derives a relatively small share of its funding from donors abroad. Rather, ISIL generates wealth from economic activity within the territory it controls. This makes it difficult to constrain its funding."
Nevertheless, Szubin said the U.S. was working with Iraq to cut off banks in ISIS-controlled territory from the international financial network, and that it had sanctioned more than 30 ISIS leaders and financiers. The U.S.-led military coalition had also begun, he said, to bomb ISIS' "key energy assets," including oil fields, refineries, and tankers.
Szubin reportedly deviated from his prepared remarks, telling his audience in London that ISIS had been "selling a great deal of oil to the Assad regime," far more than made its way into Turkey or Kurdish-controlled areas there and in Iraq.
Russia has previously accused Turkey of being the primary destination of oil from ISIS, alleging Turkish President Recep Erdogan and his son-in-law, Berat Albayrak, the new energy minister and former CEO of an Istanbul-based conglomerate, were orchestrating the resale of oil coming from ISIS, an allegation Ergoan called a "slander."
Earlier this week at a Senate hearing, Defense Secretary Ashton Carter opened the door to redeploying troops to Iraq, but also warned such an escalation would "Americanize" the conflict and fuel "a call to jihad" in the region.
In an address to the nation from the Oval Office on Sunday, President Barack Obama described ISIS as part of a terrorist threat that's "evolved into a new phase" after the U.S. limited the ability of terrorist groups to perpetrate "complex, multifaceted attacks like 9/11," saying the U.S. and its allies were ramping up their military campaign against ISIS and its infrastructure in the wake of the November 13 ISIS attacks in Paris.
The United States continues to insist the political solution to the war in Syria will require Bashar Assad, a Russian ally, to step down. Critics of the Syrian regime accuse it of avoiding a confrontation with ISIS and even creating space for it in order to weaken the broader rebel movement, part of which the U.S. supports.
Meanwhile, Russian airstrikes against Syrian rebels, ISIS, and other terrorist groups (how much attention is paid to each depends on who you ask) continue, with Turkey accusing the country of perpetrating an "ethnic cleansing."