ISIS earns millions of dollars a month running car dealerships and fish farms in Iraq, making up for lower oil income after its battlefield losses, Iraqi judicial authorities said on Thursday.
Security experts once estimated the ultra-radical Islamist group's annual income at $2.9 billion, much of it coming from oil and gas installations in Iraq and Syria.
The US-led coalition has targeted ISIS's financial infrastructure, using air strikes to reduce its ability to extract, refine and transport oil and so forcing fighters to reportedly take significant paycuts.
Yet the terrorists, who seized a third of Iraq's territory and declared a caliphate in 2014, seem to be adapting again to this latest set of constraints, in some cases reviving previous profit-turning ventures like farming.
"After the armed forces took control of several oil fields Daesh was using to finance its operations, the organisation devised non-traditional ways of paying its fighters and financing its activities," the report added, using an Arabic acronym for ISIS.
Fishing in hundreds of lakes north of Baghdad generates millions of dollars a month, according to the report. Some owners fleeing the area abandoned their farms while others agreed to cooperate with ISIS to avoid being attacked.
Fish farms have supplied terrorists with income since 2007 when ISIS's al Qaeda predecessor fought US occupation forces but the mechanism only came to the authorities' attention this year, the report said.
The terrorists also tax agricultural land and impose a 10 per cent levy on poultry and other duties on a range of imports into their territory, it added.
New revenues are also being generated from car dealerships and factories once run by the Iraqi government in areas seized by the terrorists.
Those have helped offset the losses from lower oil income, though perhaps only partially. The US-based analysis firm IHS said last week that ISIS revenues had fallen by around a third since last summer to around $56 million a month.
"In the recent period, Daesh has gone back to using government factories in the areas it controls - like Mosul - for financial returns," Huchaimi said, but added that oil smuggling from Syrian refineries remains the group's primary source of international financing.