ISIS has estimated that its budget for 2015 is $2 billion, which reportedly includes a $250 million surplus.

According to the Pentagon, the terror group is no longer getting the bulk of its income from oil revenue, instead turning to black market and smuggling operations.

Daveed Gartenstein-Ross, senior fellow at the Foundation for the Defense of Democracies, said on "Happening Now" that ISIS is getting less money from oil because coalition airstrikes have targeted their refineries and the oil market has collapsed.

Gartenstein-Ross said that ISIS is generating new revenue by imposing taxation on its population and by selling anything it can get its hands on, including antiquities and property in the areas it controls, largely taken from those who fled.

"It's clear that their figure of their surplus should not be taken seriously," he said. "They do have a treasury, but let's be very clear. There are no accountants coming in to perform outside audits to show that this is a credible figure in any way, shape or form. This is ISIS claiming that it has a surplus."

Gartenstein-Ross added that ISIS has been known to portray areas of weakness as strengths, casting even more doubt on their figures.

"We should question that, especially because we know the economy has absolutely collapsed in places that it controls, such as Mosul, where the price of food, the price of meat has shot through the roof," he said.

Gartenstein-Ross said that ISIS's unstable financial situation will be a part of what will eventually cause the organization to unravel.

He said that the media and ISIS itself often portray the group as a greater threat than it really is, but there is no doubt that jihadism is in a growth period worldwide.

"ISIS itself is one player among a number," Gartenstein-Ross said. "I think that Al Qaeda overall is much stronger in North Africa and basically everywhere in the world other than Iraq and Syria, where ISIS is the dominant military force."

He said that the many brutal acts that ISIS is committing will come back to haunt the organization, whereas Al Qaeda is handling itself much more strategically.

"We need to be aware of the full range of players," he concluded.

Watch the clip above.