The European Union-mandated study showed that 51 companies from countries including Turkey, Brazil, and the United States produced, sold or received the more than 700 components used by Islamic State to build improvised explosive devices (IEDs), as reported by Reuters.
IEDs are now being produced on a "quasi-industrial scale" by the militant group, which uses both industrial components that are regulated and widely available equipment such as fertiliser chemicals and mobile phones, according to Conflict Armament Research (CAR), which undertook the 20-month study.
Islamic State controls large swathes of Iraq and Syria. NATO member Turkey shares borders with both countries and has stepped up security to prevent the flow of weapons and insurgents to the hardline Sunni group.
A total of 13 Turkish firms were found to be involved in the supply chain, the most in any one country. That was followed by India with seven.
"These findings support growing international awareness that IS forces in Iraq and Syria are very much self-sustaining — acquiring weapons and strategic goods, such as IED components, locally and with ease," said James Bevan, CAR's executive director.
The sale of these cheap and readily available parts, some of which are not subject to government export licenses, is far less scrutinized and regulated than the transfer of weapons.
The study found that Islamic State is able to acquire some components in as a little as a month after their lawful supply to firms in the region, suggestion a lack of oversight in the supply chain.
"Companies having effective accounting systems to establish where the goods went after them would act as a deterrent," Bevan said.
Companies from Brazil, Romania, Russia, the Netherlands, China, Switzerland, Austria and Czech Republic were also involved, the report found.