"Despite battlefield losses, ISIS continues to operate its own terrorist pseudostate and claims a growing global footprint. At least 34 radical Islamist groups have pledged their allegiance to ISIS. As of this printing, the organization has managed to expand its presence to dozens of countries and territories-in addition to recruiting tens of thousands of fighters from over 120 nations. Most alarmingly, ISIS is driving an unprecedented surge of terror plots against the West and poses a persistent and grave threat to the U.S. homeland. Their explosive growth stems in part from its ability to control territory and generate massive revenue flows from diverse sources. ISIS is unique in comparison to other terror groups in that it runs a state-like infrastructure designed to raise revenue and support government functions, such as providing social welfare services and waging war. While the United States has made progress in blunting the group's momentum in Iraq and Syria, ISIS has proved to be a flexible and determined enemy that will regenerate and spread unless its revenue streams are cut off decisively. Given the severity of the threat, the House Homeland Security Committee launched a review to examine ISIS' financial infrastructure and U.S. Government's efforts to dismantle it. The Committee's Majority Staff reviewed the group's revenue streams, examined U.S. Government activities to counter its finances, and developed findings and recommendations related to the issue."
U.S. House of Representatives, Committee on Homeland Security: http://www.homeland.house.gov/