Bitcoin plunged by 25 percent to a six-week low early Wednesday due to growing fears of a regulatory crackdown in South Korea. The cryptocurrency briefly dropped below $10,000. Rival cryptocurrencies also plummeted, some by even greater percentages than bitcoin. South Korea has walked back a vow to ban sales of bitcoin, but the country's finance minister, Kim Dong-yeon, said "the shutdown of virtual currency exchanges is still one of the options" open to the government. Reports last week said South Korea was working on discouraging speculative cryptocurrency trading behind their meteoric rise this year. South Korea said it wouldn't make a move until it had time for "sufficient consultation and coordination of opinions."