High-quality counterfeits of American $100 and $50 are keeping North Korea's economy afloat, The End of Money author David Wolman reports in Time. Estimates on Pyongyang's black market counterfeiting profits range from $15 to $25 million "to several hundred million dollars' worth" every year.
Wolman imagines an America without high-denomination bills:
[C]onsider for a moment what it would mean to get rid of high-denomination banknotes. Who would be most inconvenienced if Washington were to outlaw $100 and $50 bills tomorrow? Cartel bosses in Juarez, Mexico jump to mind. So do human traffickers in China and Africa, aspiring terrorists in Afghanistan, wildlife poachers, arms dealers, tax evaders, and everyday crooks who hold up mom and pop groceries. And, of course, North Korean government officials.