Bitcoin plummets more than 12 percent, dropping below $15,000 in Asian trading

Bitcoin tumbled more than 12 percent in volatile Asian trading on Friday, dropping below the $15,000 level after touching a record high above $16,000 earlier in the session.

Bitcoin was down 12.6 percent on the Bitstamp exchange at $14,500.76 as of 0530 GMT, after rising to a record $16,666.66 .

It was still up more than 30 percent for the week, as investors debated about whether the cryptocurrency was in a bubble that was about to burst.

Major banks in the U.S. took notice, with three of the biggest saying they will either limit or not allow their clients access to the futures when trading begins next week on the Chicago Board Options Exchange.

In the U.S., the volatile digital currency surged above $19,000, dropped back below $16,000, and then see-sawed before settling in just above $17,000 within a few hours late Thursday. The wild swings happened just days before trading in bitcoin futures begins on a major U.S. exchange.

Major banks took notice, with three of the biggest saying they will either limit or not allow their clients access to the futures when trading begins next week on the Chicago Board Options Exchange.