Michael Bloomberg, the ex-New York City mayor, is worried the current field of candidates is not good enough to beat Donald Trump in the 2020 election, his adviser says.
The 77-year-old is expected to file paperwork this week for the Democratic presidential primary in Alabama.
There are a total of 17 Democratic candidates who are planning to take on President Trump.
Former Vice-President Joe Biden, Massachusetts Senator Elizabeth Warren and Vermont Senator Bernie Sanders are the frontrunners.
Some recent polls have indicated that Warren and Sanders – who are regarded as to the left of Biden – might lose against Trump if either won the party’s nomination.
So far, three Republicans have said they will challenge Trump in the party’s primary contest.
But it is seen as next to impossible that anyone will take the Republican mantle from the president.
In a statement, advisor to Bloomberg Howard Wolfson, said: “We now need to finish the job and ensure that Trump is defeated.”
“But Mike is increasingly concerned that the current field of candidates is not well positioned to do that.
“Based on his record of accomplishment, leadership and his ability to bring people together to drive change, Mike would be able to take the fight to Trump and win,” Mr Wolfson said.
President Trump has so far made no public comments on the issue.
The Democratic nominee for the presidential election will be selected after a series of electoral contests across the country.
Bloomberg has, I understand, been doing a lot of polling in early voting states like Iowa and New Hampshire. In the past he’s ruled himself out because he thought Americans wouldn’t vote for a billionaire New York businessman. That concern no longer applies.
Bloomberg’s net worth is $52 billion, according to Forbes. This is nearly 17 times more than that of President Trump. He was a Wall Street banker who went on to found the financial publishing empire that bears his name. He has donated millions of dollars to educational, medical and other causes.
Originally a Democrat, he became a Republican to mount a successful campaign for mayor of New York City in 2001. Bloomberg went on to serve three terms as mayor until 2012, rejoining the Democratic Party only last year.