The Islamic State is hemorrhaging money with every piece of territory it loses, according to a new analysis that found the group’s “business model” is on the path to failure.

The analysis released Saturday by the International Centre for the Study of Radicalisation and Political Violence and the accounting firm EY found that the self-proclaimed caliphate’s financial resources have been drained substantially since the days beginning in mid-2014 when it captured banks, oil wells and entire warehouses of weapons as it amassed land.

The report found that Islamic State revenue has declined from up to $1.9 billion in 2014 to at most $870 million in 2016.

“One of the mistakes that’s been made in the past when we were talking about Islamic State was talking about it purely as a terrorist organization. It is a terrorist organization but it is more than that. It holds territory,” said Peter Neumann, director of the center at King’s College London. “That also means it has a lot more expenses. It needs to fix roads. It needs to pay teachers. It needs to run health services. It needs to pay for these things that al-Qaida never had to.”

But less money may not make the group less dangerous, the report said.

“We know from the attacks in Paris and Brussels and Berlin that none of them was expensive,” Neumann said.

Most of the recent attacks in Europe and the U.S. were self-financed by the people who carried them out, with little input or money from the leadership in the war zone of Syria and Iraq.

Among the top sources of revenue for the Islamic State were taxes and fees, oil, ransoms, and looting or other extortion. All of those, Neumann said, required newly captured territory to be sustainable and to keep the group’s promise of a caliphate.

But that income only flows when the Islamic State can exert absolute control.