At a Chatham House event a day earlier, O'Neill, former chairman of Goldman Sachs Asset Management, noted that he had been sitting in the same exact seat in which Draghi made his "whatever it takes" comment two years ago.
"And it reminds me, obviously having worked with the guy at some point, he shouldn't be underestimated," O'Neill said. "So, I think the key is what he says, as opposed to what they do. He knows what he's done by setting the market up to have some strong expectations to some rate cut and maybe more. I think the thing to really watch will be what he has to say about any follow-up moves and any subtleties about the importance of the euro."
European equities closed lower a day ahead of the ECB meeting in anticipation of stimulus measures.