Bitcoin prices fell below $4,000 mark for the first time in a month on Wednesday as investors continued to dump the cryptocurrency following a clampdown on cryptocurrencies in China and accusations of fraud from one of Wall Street's most influential bankers.

Bitcoins were marked at $3,966 each on the Bitsmap exchange in London, the lowest since Aug. 13 and down about 5% from Tuesday night's levels following a series of disparaging comments from JPMorgan Chase & Co. (JPM) - Get Report  CEO Jamie Dimon, who called the virtual currency concept a "fraud" and said he'd fire any of his traders for dealing in it. So far this month, however, bitcoin prices have fallen nearly 20%, or more than $1,000, from the all-time peak the virtual currency reached on Sept. 1.

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