U.S.-led coalition air strikes against Islamic State of Iraq and Syria (ISIS) oil facilities have cut the militant group’s oil revenues by about 30 percent since October, a coalition spokesman said on Wednesday

ISIS, an adversary the United States calls the wealthiest terrorist group of its kind in history, derives funds from a variety of sources, including sales of oil produced in territory it controls, extortion, and sales of antiquities, experts say.

In October, the U.S. military launched an intensified effort to go after oil infrastructure controlled by ISIS, dubbed “Tidal Wave II,” named after the bombing campaign targeting Romanian oil fields in World War Two. […]