Tannenbaum joined BMO in 2010 and has held multiple leadership roles, most recently leading global investment and corporate banking, where he worked with corporate, government and financial sponsor clients worldwide. Before then, he headed the global corporate finance solutions group, where he was responsible for capital raising activities.

Tannenbaum will be challenged with boosting the bank's capital market business, which accounts for roughly a fifth of its overall profit, at a time that deal and IPO activities have slowed amid market turmoil.

CEO Darryl White said Tannenbaum is "well-positioned to capture new growth opportunities" for BMO Capital Markets.

In June, BMO slashed hundred of jobs in the capital markets segment in response to a weak environment for mergers and acquisitions, and incurred costs related to severance in the third quarter.

With 25 years of experience on Wall Street, Tannenbaum has also spent over a decade at Lehman Brothers, where he led European equity capital markets in London and U.S. institutional sales based in New York.

Barclay, who is retiring following his 32-year investment banking career, will continue with the bank as a senior adviser to CEO White.

Brad Chapin will take over for Tannenbaum as global head, investment and corporate banking on an interim basis, BMO said.

(Reporting by Nivedita Balu in Toronto; editing by Jonathan Oatis)