Bitcoin down 5% on Friday to a one month low. Analysts say the dip is caused by fears of regulation, rumours of an exchange hack, and news of a big seller in the market. LONDON — Bitcoin is slumping on Friday, down by 5% in early morning trade to trade at a one month low. Analysts say that the slump is being caused by a string of bad headlines for the sector this week that have dented investor sentiment.