Ray McGuire, one of the senior-most Black executives on Wall Street, is leaving his job at Citigroup Inc. to run for mayor of New York in 2021, his spokeswoman said on Thursday.

Although McGuire is a longshot in the race, a successful candidacy would make him only the second Black mayor of America's largest city, after David Dinkins' stint as New York mayor in the 1990s.

"It is correct that he is exploring a run for mayor ... he has taken the first step in doing that, which is that he has filed with the Campaign Finance Board in New York City," the spokeswoman said.

Current Mayor Bill de Blasio will step down after his current term, as city laws prevent him from seeking a third term.

Citi's chief executive, Michael Corbat, told employees that McGuire will leave the bank after 15 years in various roles to pursue his "lifelong passion for public service," according to a memo seen by Reuters.

McGuire headed Citi's corporate and investment banking unit for 13 years and was most recently also chairman of banking, capital markets and advisory. Prior to Citi, 63-year-old McGuire was at Morgan Stanley.

The move into politics for McGuire, who until recently held the title of vice chairman at Citi, comes after he was on a short list of candidates to head the New York Federal Reserve in 2018.

McGuire is not the first Wall Street executive to dabble in politics. Billionaire Michael Bloomberg was New York mayor from 2001-2013, and Phil Murphy, a former Goldman Sachs banker, is the current governor of New Jersey.

The New York Times first reported McGuire's decision to run for mayor earlier Thursday.