Bloomberg made the announcement at a City Hall news conference, The New York Times reported. He called another term "a challenge that I would like to take on for the people of New York.'
A third term for Bloomberg got a boost this week when Ronald Lauder, the billionaire cosmetics heir who bankrolled the term limits movement, said he would like to see Bloomberg remain the mayor. Lauder described his change of heart as a one-time thing, fueled by the economic crisis and Bloomberg's Wall Street experience.
Former mayors Rudolph Giuliani and Edward Koch, whose scandal-ridden third term fueled the term limits movement, have also backed Bloomberg.
Bloomberg made a fortune after founding the business news service that bears his name. A Democrat, he switched to the Republican Party to run for mayor and last year became an independent.