UBS' Bob Mulholland, head of the firm's Client Advisory Group, is retiring, according to a memo sent out Tuesday afternoon to employees from UBS Americas President Bob McCann.

Mulholland will be replaced by Brian Hull, who has served as chairman and head of Strategic Clients & Partnerships.

Hull joined UBS from Merrill Lynch in 2009, according to the firm's website. While at Merrill, Hull served as head of the Private Banking and Investment Group, the firm's elite brokerage unit that serves ultrawealthy clients.

McCann said that he's known Hull for 25 years, both as a colleague and client.

"Outside of his day-to-day responsibilities, Brian is one of UBS's most ardent 'culture carriers,'" McCann said in the memo. "His commitment to developing talent has earned him the respect of colleagues across our organization, while his dedication to always putting the interests of clients first has deepened our most important relationships. Simply put, Brian leads by example and embodies the UBS principles and behaviors."

Mulholland is ending a 36-year career in the industry. Like other UBS executives, Mulholland previously worked at Merrill. He started his career there in 1979 and stayed for 25 years.

According to the memo, Mulholland and his wife are anticipating the birth of their first grandchild.

"I wish Bob much happiness during this exciting next chapter, and look forward to his continued friendship," McCann said in the memo.

Executives Bill Carroll and Jason Chandler will continue in their current roles overseeing the firm's roughly 7,000 advisors in two regions, West and East.

John Mathews, who oversees the firm's Private Wealth Management unit, will join Chandler and Carroll on UBS' executive council, according to the memo. Matthews will also now oversee the Americas Global Family Office and Business Development Group.

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