SEOUL (Reuters) - JPMorgan Chase & Co (JPM) Chief Executive Jamie Dimon said the U.S. economic downturn was likely to last at least 12 months, further hurting the global economy, South Korea's Yonhap News reported.

Speaking on Thursday at a lecture to Korea Development Bank staff, Dimon was quoted as saying global financial market conditions would somewhat stabilize in three to four months time, thanks to bold stimulus measures taken by central banks and governments worldwide.

But markets would not recover to their level before the financial crisis for the time being, Yonhap quoted the head of the biggest U.S. bank as saying.

Dimon also predicted the investment banking industry would see sophisticated derivatives trading and principal investment using borrowings shrinking significantly.

Growth could continue in the areas of advising mergers and acquisitions, credit markets and risk hedging, Dimon said, according to Yonhap.

(Reporting by Rhee So-eui; Editing by David Cowell)