Bitcoin slides another 16%, falling below $50,000 as Janet Yellen raises the alarm

Bitcoin slides another 16%, falling below $50,000 as Janet Yellen raises the alarm

Bitcoin's price descended further on Tuesday after U.S. Treasury Secretary Janet Yellen issued a warning about the cryptocurrency.

The world's most valuable digital coin plunged 16% in the last 24 hours, sinking below $50,000 to trade as low as $45,389 at 4:10 a.m. ET, according to data from Coin Metrics.

Smaller digital tokens like ether and XRP also tumbled. Ether slipped 15% to a price of $1,497 while XRP sank 21% to trade around 45 cents.

On Monday, Yellen called bitcoin an "extremely inefficient way of conducting transactions" and warned about its use in illicit activity. She also sounded the alarm about bitcoin's impact on the environment. The token's wild surge has reminded some critics of the sheer level of electricity required to produce new coins.

Bitcoin isn't controlled by any central authority. So-called miners run high-power machines which compete to solve complex math puzzles in order to make a transaction go through. Bitcoin's network consumes more electricity than Pakistan, according to an online tool from researchers at Cambridge University.

Yellen also warned about the risks of bitcoin investing to retail investors Monday.

"It is a highly speculative asset and you know I think people should be aware it can be extremely volatile and I do