Some economists have responded positively to bitcoin while others have expressed skepticism. François R. Velde, Senior Economist at the Chicago Fed, described it as "an elegant solution to the problem of creating a digital currency".[222] Paul Krugman and Brad DeLong have found fault with bitcoin, questioning why it should act as a reasonably stable store of value or whether there is a floor on its value.[223] Economist John Quiggin has criticized bitcoin as "the final refutation of the efficient-market hypothesis".[186]
