Getty Images LONDON/GUANGZHOU, China — Bitcoin and other digital currencies plunged on Friday as a proposed capital gains tax hike from U.S. President Joe Biden led to a wave of selling. At around 10 a.m. London time, bitcoin was down over 8% in the last 24 hours at $48,687, according to Coin Metrics data. It's the first time bitcoin has traded below $50,000 since early March. Ether fell to $2,211, down more than 12%. XRP, the fifth-biggest cryptocurrency, plunged nearly 19%. This wiped out more than $200 billion of value from the entire cryptocurrency market, according to data from CoinMarketCap. "The market has run up quite a bit overall, and it's probably cooling off before the next leg up," Vijay Ayyar, head of business development at cryptocurrency exchange Luno, told CNBC by email. President Biden is expected to raise long-term capital gains tax for the wealthiest Americans to 43.4%, including a surtax. That would be higher than the top federal tax