Bitcoin is still dropping

Bitcoin is still falling against the dollar on Friday after losing more than a fifth of its value in trade on Thursday.

Bitcoin is down over 7% against to $944.14 at just after 9.30 a.m. GMT (4.30 a.m. ET), according to Markets Insider. That's down from over $1,100 earlier in the week.

Bitcoin surged in the weeks running up to Christmas, battled volatility in the run up to New Year and first few days of 2017, before tanking on Thursday.

The exact reasons for the currency's rise and fall are unclear, but some commentators have suggested that the rise was caused by Chinese investors looking to move their money out of China ahead of a rumoured further devaluation of the renminbi. This theory is backed up by moves in the renminbi yesterday which coincided with bitcoin's plunge. The renminbi rallied 2.6% against the dollar, posting its biggest two-day gains ever.

Mati Greenspan, a senior market analyst at trading platform eToro, says in an email on Friday morning: "We can see a huge correlation between the two currencies with the USD/CNH often acting days or even months ahead of Bitcoin."

But he adds: "If we drill down, we can see that the $150 plunge that we saw in bitcoin actually came hours after the PBoC's nuke [data from the People's Bank of China that caused the renminbi to spike]."