LONDON—Bitcoin tumbled below the $40,000 mark on Wednesday to a three-and-a-half month low as selling in digital coins intensified after China banned financial and payment institutions from providing cryptocurrency services.
Bitcoin, the biggest and best-known cryptocurrency, had already been under pressure from a series of tweets from Tesla boss Elon Musk, but the news from China sent it as low as $36,250, a 15 percent drop in the trading session.
