He holds an honorary knighthood and uses public transport to go to work both in London, where he has a home, and New York.
And he is far wealthier than Donald Trump.
Meet Michael Bloomberg, the Democrat-turned-Republican-turned-independent-turned-Democrat, who is mulling over taking on the US president in an electoral battle of the billionaires in 2020.
The 77-year-old media magnate and philanthropist, who served three terms as the mayor of New York City, is reportedly putting together a powerful campaign team and has already spent millions of dollars gearing up for a sophisticated data-driven assault on the White House.
He has little affection for Mr Trump, a man with whom he has played golf and even joined at a New York Yankees baseball game.
US election 2020 | Democrats running for President
“My objection to Donald Trump is the way he’s filling his current role, in terms of representing the country, in terms of representing the public,” he said in New Hampshire recently.
“There’s an attitude, and a style and lack of civility that I think is bad for the country, and I find offensive.”
There has been scuttlebutt about Mr Bloomberg running for president for more than a decade, albeit as a centrist independent rather than as a Democrat, having rejoined the party last year.
“He stands out by comparison with the other candidates because he occupies more moderate space in the party, being conservative on economic issues and liberal on social issues,” said Robert Shapiro, political science professor at Columbia University.
Unlike many of his potential rivals, Mr Bloomberg will not have a recognition problem. According to one estimate, he is the eighth richest person in the US, having made a fortune as the man behind the computerised information system used by the financial services industry.
Politically he made his name as New York’s mayor, taking office a matter of months after the September 11 terrorist attacks on the city.
A lifelong Democrat, he ran as a Republican, following in the footsteps of liberal members of the party like John Lindsay who served as the city’s mayor.
The Democrat tribes fighting it out for their party’s 2020 presidential nomination
Wealthy enough to turn down a mayor’s salary, Mr Bloomberg accepted a token $1 a year for his services. He is best remembered for his war on smoking, trans fats and fizzy drinks.
The consensus is that he was an effective administrator – popular enough to persuade voters to give him a third term in office, tossing aside legislation limiting mayors to two.
"He is the greatest mayor the city of New York has ever had," said Erich Ulrich, a long-serving Republican member of the council. "New Yorkers were lucky to have him at the helm for 12 years."
Jimmy Van Bramer, the city council’s deputy leader and a Democrat, was also impressed.
“I think he is no-nonsense, direct and at times humorous. He is very focused on what he thinks is the right approach to problem-solving,” he said.
“He can sprinkle salty language into any conversation. He can be arrogant, but that is a trait common among billionaires. He can also be dismissive when people disagree with him and put it down to politics.
“His greatest strength is as a manager. He delegates and as mayor, he hired very good people to be commissioners. He ran a finely tuned operation, but that is not to say he always got it right.”
Few doubt his ability to do the job. “He is the adult in the room,” said Doug Muzzio, a political scientist at Baruch College in New York and a longtime observer of the city’s politics.
“He is experienced in government as a three-term mayor of New York City, has built up a media and technological empire and is one of the richest men in the United States.
“His governing approach was neoliberal and he was criticised for saying New York is a luxury city, a sandbox for the elite.
“He is going at it from a position of wealth and power which is checked by real social conscience.”
Mr Bloomberg has a long-standing association with the UK. His first wife, Susan, was British and their daughters hold British passports.
His honorary knighthood, awarded in 2014, was in recognition of his business career and the £63.9 million he has donated to good causes in the UK.
In Britain, he serves as chairman of the Serpentine Galleries. A qualified pilot, he even flew a Spitfire from Duxford in Cambridgeshire last year.
Well-known to a number of senior British politicians, there is little doubt that should he become president, the UK would have a friend in the White House.
But there is a lingering doubt whether he will get the chance.
“In terms of his electoral prospects, I would argue he has none. He can’t win a Democratic primary. He can’t win as a third or fourth party candidate and he can’t win as a Republican,” Mr Muzzio added.
“The Democrats don’t want a grounded centre left, fiscally responsible and calm president who would bring in a government of high powered people. In short, he would be a better president than a candidate.”