TOKYO/LONDON (Reuters) - Bitcoin skidded more than 11 percent on Wednesday, extending a precipitous downturn in fortunes with investors spooked by fears regulators might clamp down on an asset whose value has skyrocketed in the past year. The price of the world’s biggest and best known cryptocurrency fell to as low as $10,065 on the Luxembourg-based Bitstamp exchange, a six-week low and close to half the peak price of almost $20,000 it reached in December. Other cryptocurrencies plunged as well.