https://phys.org/news/2018-06-hackers-30m-seoul-bitcoin-exchange.html > Hyper-wired South Korea has emerged as a hotbed of trading in virtual units, at one point accounting for some 20 percent of global bitcoin transactions—about 10 times the country's share of the global economy. > Bithumb, which has more than 1 million customers, is the largest virtual currency exchange in the South.