Various journalists, economists, and the central bank of Estonia have voiced concerns that bitcoin is a Ponzi scheme. In 2013, Eric Posner, a law professor at the University of Chicago, stated that "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems more like a collective delusion." A 2014 report by the World Bank concluded that bitcoin was not a deliberate Ponzi scheme. The Swiss Federal Council examined the concerns that bitcoin might be a pyramid scheme; it concluded that "Since in the case of bitcoin the typical promises of profits are lacking, it cannot be assumed that bitcoin is a pyramid scheme." In July 2017, billionaire Howard Marks referred to bitcoin as a pyramid scheme.On 12 September 2017, Jamie Dimon, CEO of JP Morgan Chase, called bitcoin a "fraud" and said he would fire anyone in his firm caught trading it. Zero Hedge claimed that the same day Dimon made his statement, JP Morgan also purchased a large amount of bitcoins for its clients. In a January 2018 interview Dimon voiced regrets about his earlier remarks, and said "The blockchain is real. You can have cryptodollars in yen and stuff like that. ICOs ... you got to look at every one individually."