https://www.reuters.com/article/us-markets-bitcoin/bitcoin-other-cryptocurrencies-tumble-on-government-crackdown-worries-idUSKBN1F50UL >Bitcoin slid as much as 18 percent on Tuesday to a four-week low, as worries about a regulatory crackdown on the market spread after reports suggested it was still possible that South Korea could ban trading in cryptocurrencies.