The coalition bombing campaign has destroyed ISIS's capacity to produce oil, however reports suggest the terror group has found other sources of funding.
Although ISIS has lost much of its oil producing infrastructure, experts believe they have not lost much of their revenue, thanks to a change in strategy. ISIS has moved its source of revenue from black market oil sales to taxing the people living in their territory. While the bombing campaign has reduced their revenue by $500 million, ISIS still made $2.4 billion in 2015, making them the richest terror organisation in the world.
Furthermore, according to expert Christina Schori Liang, ISIS has begun using cybercrime as a source of revenue. This will make ISIS revenue harder to track, and harder to shut-down.