Bitcoin tumbled by more than 4% in a matter of 15 minutes on Wednesday after Bloomberg reported that the People's Bank of China was meeting with several local bitcoin exchanges to discuss money-laundering concerns.

Bitcoin has had a wild start to 2017 after gaining 120% in 2016 to become the top-performing currency for the second year in a row. The cryptocurrency raced to a gain of 20% in the opening days of the year as speculators, mainly from China, poured in.

Bitcoin then crashed 35%, however, on fears that China would crack down on trading, bottoming near $750 a coin. Then the cryptocurrency managed to grind higher despite news that China's three largest exchanges said they would implement a flat fee of 0.2% on all transactions.

Bitcoin is now trading down 1.5% at $1,036 a coin. It's up almost 9% for 2017.