Its largest export was coal; the report concluded that North Korea exported $413.6 million in coal in that time frame — $12.7 million above the United Nations cap. North Korea also sold $62.1 million in iron and steel, exports that violated sanctions.

Using front companies, manipulations of automated signals that radar systems use to detect global shipments, and ship-to-ship transfers in the middle of the night, North Korea was able to “give the impression that the coal was loaded in ports other than in the Democratic People’s Republic of Korea,” the report said.

Still, “We’re really forcing the North Koreans to jump through hoops,” said Andrea Berger, a senior research associate and senior program manager at the James Martin Center for Nonproliferation Studies in Monterey, Calif.

“North Koreans are literally physically concealing the identity of ships at night and doing ship-to-ship transfers,” she said. “That’s not something you do unless you have to.”

Financial Transactions Abroad

North Korean firms and individuals, utilizing front companies and working with foreign citizens, have opened bank accounts around the world.

The report said some of the country’s banks “maintain a network of overseas representatives who continue to move freely across borders to undertake transactions in multiple countries and to establish residences abroad.”