The militant group faced financial hardship after it lost its oil income after being hit hard by US-led coalition forces in Iraq.
Income from these non-traditional business is being used by the ISIS to pay their fighters and finance their activities as they are pushed out of the territory they once held.
According to reports, they are earning millions of dollars a month running car dealerships and fish farms in Iraq.
The group's annual income was around $2.9bn (£1.98bn) when they declared their caliphate in 2014.
Amid financial hardship, the ISIS decided to reduce the salaries of all its militants by 50 percent earlier this year.
Before being hit by airstrikes, the ISIS generated huge wealth from oil smuggling which is used to fund its operations, paying fighters a monthly salary and providing assistance to their families.
Hundreds of dollars were destroyed in the airstrikes carried out by US-led coalition forces
"The terrorists' current financing mechanism has changed from what it was before the announcement of the caliphate nearly two years ago," a report by Iraq's central court of investigation said, quoting Judge Jabbar Abid al-Huchaimi.