Bitcoin speculators had a jittery week, pushing the cryptocurrency down from a record high. Janet Yellen, America’s treasury secretary, added to the febrile atmosphere when she described bitcoin as an “extremely inefficient way of conducting transactions”. Meanwhile, New York state’s attorney-general branded Tether “fraudulent” and barred the stablecoin—commonly used to buy bitcoin on crypto-exchanges—from trading in New York. Tether long claimed its coin was backed one-to-one by the dollar, but New York concluded that it overstated its reserves and is “a stablecoin without stability”.
The knock to bitcoin was a factor behind a sharp fall in Tesla’s share price. The electric-car maker made a controversial $1.5bn investment in bitcoin recently. Shortly before the cryptocurrency plunged, Elon Musk mused that its price seemed “too high”. The drop in Tesla’s stock at one point wiped $15bn off his fortune.