Bitcoin edged lower on Friday and headed toward its worst week since March, as investors shrugged off a regulatory victory for virtual currencies and focused on a string of negative news, including cyber heists.

The largest cryptocurrency fell 2.1 per cent to US$6,518 as of 8:38 a.m. in New York. Ether also slipped on Friday, giving back much of Thursday’s 10 per cent jump following a statement by the top U.S. markets regulator that transactions involving the world’s second-biggest token aren’t subject to federal securities rules.

Even as the 10 largest, most liquid coins on Friday traded little changed, the group is still down 19 per cent for the week, with the industry fighting the perception that long-time investors are taking advantage of days with positive news to sell peer-to-peer money.

Questions swirled this week about whether the world’s biggest cryptocurrency was manipulated during last year’s record price surge after a University of Texas professor published a study flagging suspicious activity. And over the weekend, currency exchange Coinrail said in a statement that some of its digital currency appears to have been stolen by hackers, but it didn’t disclose how much, adding to a string of cyber heists.

A Ripple executive pushed back against the Reserve Bank of India’s moves to restrict banks from dealing with digital coins, the Times of India reported. The company expects Basel norms and RBI’s own report on the industry to lead to the ban being rescinded, the newspaper reported.