Bitcoin extends gains, rises above $12,000 to record high

TOKYO, Dec 6 (Reuters) - Bitcoin retained its overnight momentum and rose to a record high of $12,205.46 on Wednesday, continuing its rally from below $1,000 at the year's start.

The cryptocurrency was last up 4.35 percent at $12,185.70 on the Luxembourg-based Bitstamp exchange. (Reporting by the Tokyo markets team; Editing by Sam Holmes)