Bitcoin up 9 percent, hits $4,000 for first time in two weeks

LONDON (Reuters) - Bitcoin rallied more than 9 percent on Thursday, hitting $4,000 for the first time in more than two weeks after losing half its value in six weeks to mid-December.

The world's most valuable cryptocurrency has been hit hard this year, falling around 80 percent from a record high last December on concerns of increased regulatory scrutiny.

On Thursday, bitcoin gained as much as 9 percent at $4,030.15, its highest since Dec. 4, before retreating slightly.

(Reporting by Abhinav Ramnarayan; Editing by Saikat Chatterjee and Kevin Liffey)