Bernie Sanders is calling it the " contest between billionaires ."
Reports surfaced over the weekend that Bloomberg, founder of financial information and media firm Bloomberg LP, is putting out feelers for a potential third-party run for the White House.
Though the possibility of him entering the race comes with plenty of caveats — for example, he would likely only do so if Sanders wrestled the Democratic nomination from Hillary Clinton, according to The New York Times — one expert said his entry could force Trump to "pivot" his message away from his own wealth creation.
According to an average of estimates provided by two independent firms, Bloomberg is worth nearly nine times Trump. And unlike the Republican candidate, he has a shown a willingness to spend it on campaigns.
Forbes estimates place Bloomberg's net worth at $36.5 billion, making him the ninth richest man in America. Wealth-X, the independent research firm, puts his net worth at $42.1 billion.
Trump's wealth is a little more contentious. Forbes says he's worth $4.5 billion, while Wealth-X pegs him at $4.4 billion. Bloomberg News, which does not tabulate Bloomberg's wealth, tallied Trump's net worth at $2.9 billion.
In July, that calculationprompted Trump to say the organization vastly undercounted his fortune because the former mayor was "jealous." Trump has said he's worth more than $10 billion .
And while Trump said he would welcome a Bloomberg run, his campaign rhetoric may force him to shift his message away from his own wealth creation, and acknowledge that Bloomberg is far richer.
"Donald Trump has built his brand around the wealth he has created and uses that argument to support his capability to get things done in the politic sphere," said David Friedman, president of Wealth-X.
"By his own logic, should Bloomberg enter the fray, [Trump] will need to pay homage to the fact that Bloomberg has created as much as 10 times the wealth he has generated for himself, according to Wealth-X estimates."
Beyond having a bigger war chest, Bloomberg has also shown a willingness to spend it on elections. He spent an estimated $268 million on his three races for mayor — the largest self-financed amount for any political candidate in U.S. history.
He spent more than $380 million in additional money on pet projects and city charities while he was mayor, bringing his total mayoral bill close to $650 million.
Trump, however, has been a big talker and a small spender. Last summer, he said he would spend up to $1 billion on his campaign, saying "I make $400 million a year, so what difference does it make?"
However, reports suggest that he has spent far less, with Trump himself saying that all the free media coverage he's getting has helped him keep his campaign $35 million under budget. Now, he says he will spend $2 million a week on ads for Iowa, New Hampshire and other primary states.
Of course, "budgets" will be relative if Bloomberg enters the race.
"It's obvious that should a political battle end up between both of them, Bloomberg has substantial more gunpowder to throw into the race," Friedman said.