A changing of the guard at Citigroup Inc. will take place as the weather gets warmer. The company announced yesterday that as of June 1, GC and corporate secretary Michael Helfer will become vice chairman, making way for Rohan Weerasinghe to assume his mantle.

Weerasinghe is currently a senior partner at Shearman & Sterling, where he has advised and represented financial institutions and corporations on issues including corporate governance, complex transactions, and IPOs and debt issues for the past 35 years. Citi’s business unit GCs, regional GCs and corporate deputy GCs will report to him.

“Rohan has a great track record as an attorney, and I have tremendous confidence in his abilities,” Citi CEO Vikram Pandit said in a statement. “I look forward to him bringing his expertise and insights to Citi. He has a strong international background, leading his firm’s relationships with multi-national corporations and financial institutions around the world, including in the emerging markets.”

Helfer, who has been Citi’s GC for nine years, has navigated the company through seriously troubled waters during his tenure. Prior to joining Citigroup, he was president of strategic investments and chief strategic officer at Nationwide Mutual Insurance Co. He had previously been a partner and chairman of the management committee at Wilmer Cutler & Pickering, and served as counsel for the subcommittee on constitutional amendments of the U.S. Senate Judiciary Committee.

“Michael has provided almost a decade of wise counsel and has experience in virtually every area where finance and the law intersect,” Pandit said. “He is an invaluable resource for this company, and we are delighted that he will continue to focus on domestic and international regulatory issues in his role as Vice Chairman.”

Pandit told the staff in a memorandum that, in his new role, Helfer will focus “on compliance, domestic and international regulatory issues and overseeing Citi’s implementation of Dodd-Frank,” the Wall Street Journal reported.