https://qz.com/1178508/koreas-bithumb-cryptocurrency-exchange-grew-so-fast-it-triggered-a-government-raid/

Korea has gone from an afterthought in the cryptocurrency markets to one of its major hubs in a matter of months. Crypto trading has grown so feverish that the government raided the country’s major exchanges to check their books—and to cool down the red-hot trading activity.

The lynchpin in the Korean market is an exchange called Bithumb, which has raked in cash as its customers have swelled in the millions. It regularly accounts for over 80% of Korea’s ether-won trade. Business was so good that the exchange struggled to develop its infrastructure to keep up with demand.