At the time, Dimon said that he would fire JPMorgan traders if they traded in the crypto-currency.
Quote
The blockchain is real. You can have crypto yen and dollars and stuff like that. ICO's you have to look at individually”, Dimon said in an exclusive interview with FOX Business’ Maria Bartiromo. “The bitcoin to me was always what the governments are gonna feel about bitcoin as it gets really big, and I just have a different opinion than other people. I'm not interested that much in the subject at all.
Source: http://www.foxbusiness.com/markets/2018/01/09/exclusive-jpmorgan-chase-chairman-ceo-jamie-dimon-regrets-saying-bitcoin-is-fraud-but-still-isnt-interested-in-it.html
The article itself sucks, but the video is worth a watch.
In my opinion, Dimon, for being a financial 'expert', is quite ignorant. He's expressed much disinterest in Bitcoin, saying that he doesn't care about it at all, but I think it's that very ignorance that led him to believe that Bitcoin was a fraud and that it would fail. He is now suffering from "foot in mouth" disease, and I'm sure there's more to come in the near future.