UBS AG's global co-head of M&A, Cary Kochman, is among four senior bankers to leave the Swiss bank on Wednesday, dealing yet another blow to a firm grappling with an exodus of dealmakers.

Kochman, who was named global co-head of M&A only in March, left for Citigroup Inc along with colleagues Jim Glerum and Justin Friesen. Friesen was deputy head of U.S. M&A at UBS, while Glerum headed diversified industrial banking.

London-based global co-head Liam Beere, who was promoted at the same time as Kochman, continues with the bank, UBS said on Wednesday.

Kochman, Glerum and Friesen, all based in Chicago, are joining former colleagues who have moved from UBS to Citi recently, including Kevin Cox and Francis Tucci.

Hong Kong-based Jason Wortendyke, head of UBS Asian industrials, also left the bank, a spokeswoman confirmed on Wednesday. It was not clear where Wortendyke was headed.

UBS has seen scores of investment bankers leave in the last three years as the financial crisis hit the Swiss bank hard and forced it to put unpopular curbs on compensation.

The bank fell to No. 13 in the first-quarter rankings of advisers involved in U.S. deals, down from No. 8 in the same period last year, according to Thomson Reuters data.

In March, the bank named new heads of investment banking across the globe as it tried to stanch the talent drain, installing Aryeh Bourkoff, a well-known media banker, as head of Americas investment banking. Bourkoff has hired bankers as he tries to build out the investment bank, but UBS continues to bleed talent.

Kochman, who joined UBS in 2004, was promoted to global co-head of M&A at the same time as Bourkoff. He will become head of North America M&A at Citi based in Chicago.

Glerum will become chairman of Citi's regional banking for North America. UBS announced earlier on Wednesday that Glerum and a few other bankers had left the firm.

The bankers' recent prominent deals include Caterpillar Inc's $7.6 billion purchase of Bucyrus International Inc late last year.

Kevin Cox, formerly head of UBS investment banking for the Americas, has advised industrial companies, including General Motors Co , Lockheed Martin Corp and Raytheon Co , while Francis Tucci covers diversified industrial conglomerates such as General Electric Co .

Jim and Cary are seasoned bankers with extensive experience acting as trusted advisers to leading multinational companies, said Raymond J. McGuire, Citi head of global banking.

Their expertise in executing complex M&A transactions across sectors and geographies matches perfectly with our global platform.

UBS said the bank is committed to its Midwest investment banking franchise, which has roughly 30 bankers. Its overall Americas investment banking employs over 750 staff, including more than 100 managing directors.

UBS is absolutely committed to building our investment banking footprint in the Americas. We have a mandate from the group to make significant investments in the U.S., Robert Wolf, President of UBS Investment Bank, said in a statement.

A source close to the bank said UBS has the capacity to pay people well, particularly those who demonstrate leadership through the current period. The majority of its about 30 global strategic hires targeted for this year will be in the United States, this source added.

(Reporting by Soyoung Kim and Paritosh Bansal; editing by Derek Caney and Andre Grenon)