The political journey of millionaire media tycoon Michael Bloomberg has taken him from being a Democrat, then a Republican and now an independent.
His decision to leave the Republican Party and change his political status to unaffiliated provoked a flurry of speculation that this was part of preparations for a run for the White House.
Michael Bloomberg is the founder of the Bloomberg media empire
Mr Bloomberg had denied any plans to stand but the latest developments show how far his profile has risen since he was first elected mayor of New York in 2001.
Then he was an unknown quantity for New Yorkers, a political novice who ran as a Republican, despite being a long-time Democratic Party supporter, and who overcame a 25-point deficit in the opinion polls to secure the office.
He was helped in no small part by his huge wealth - during his campaign he spent $41m (£20m) of his own money, more than all the other candidates combined, and was accused of trading dollars for democracy.
But perhaps more important was the endorsement by Rudolph Giuliani, the outgoing mayor who was transformed into a national hero for his handling of a city in crisis on 11 September.
Once voted Manhattan's most eligible bachelor, Mr Bloomberg's fortune is estimated to be at least $5bn (£2.5bn). He has numerous homes all over the world and a helicopter that he pilots himself.
He has also donated millions of dollars, mostly to educational, medical and cultural causes.
Mr Bloomberg was born in 1942 into a middle-class family - the son of a book-keeper.
He got his first job on Wall Street after completing his MBA in 1966.
He secured a position at Salomon Brothers, and by 1972 he had become a partner. But his relationship with the firm ended abruptly nine years later when Salomon Brothers was bought out and Mr Bloomberg was sacked.
He used his stake from the Salomon sale to found his own business - now a global media and financial data empire named after him.
Today Bloomberg LP has offices around the world and is the leading global provider of financial data.
But he wants more than this. He admits to being a man who craves admiration.
"Adulation is great," he was once quoted as saying.
As mayor, Mr Bloomberg took time to win over New Yorkers.
He raised taxes and cut costs - never vote-winners - and also garnered a reputation as a killjoy.
Smoking was banned in bars and clubs, pushing the nicotine-needy out on the streets. A crusade was also launched by Mr Bloomberg against street vendors.
In the middle of his first term his approval ratings slipped and tabloid papers began referring to the mayor as "Gloomberg".
But an improving economy, better school results and a falling crime rate helped boost his popularity in the opinion polls, and in 2005 he was re-elected.