Here's the quote: https://www.cnbc.com/2018/05/18/warren-buffett-explains-why-...
> Kenneth Cordele Griffin is an American hedge fund manager, entrepreneur and investor. He is the founder, chief executive officer, co-chief investment officer, and 80% owner of Citadel LLC, a multinational hedge fund. He also owns Citadel Securities, one of the largest market makers in the U.S.
I don’t see economist anywhere in Ken’s Wikipedia.
Just saying it doesn't count is a bit weak because that is saying training in a certain discipline and graduating in it has no meaning or skill transfer of relevance.
But I guess your point is to make sure that economists don't have any successes, not some deeper introspection into whether the study of economics can help in being successful.
Paul McCulley (an economist) made certain predictions while working at PIMCO (as did Paul Krugman), and then he left and Bill Gross (PIMCO founder) ignored what he said and made certain financial moves and lost a whole bunch of money:
* https://www.businessinsider.com/this-was-the-bill-gross-blun...
* https://www.nytimes.com/2014/10/03/opinion/paul-krugman-depr...
Gross is way richer than McCulley (or Krugman), and yet the rich guys got it wrong and the poor(er) guys got it right. If only Gross had listened to the economists (that worked for him).