The president expressed concern over vows made by Steyer and Bloomberg that they'll donate to any Democratic Party nominee.
"He is spending hundreds and hundreds of millions of dollars to buy the election," the Vermont senator said about Bloomberg. "There's something wrong with that."
The Bloomberg Billionaires Index shows that the world's 500 richest people combined grew their wealth by $1.2 trillion in the past year.
A Buttigieg spokesperson emphasized to Newsweek that the email was "not from our campaign."
Buttigieg recently faced direct criticism from fellow Democratic presidential candidate Senator Elizabeth Warren over the fundraisers.
"They have taken a decision that they will allow employees at an institution that they fund to go hungry," Timour Azhari, a journalist who resigned from his position this week, told Newsweek. "They definitely have the money to pay."
After the billionaire and possible presidential candidate reportedly spent over $30 million on ads, Bernie Sanders criticized the move, saying Bloomberg can't "buy this election."
Trump 2020 press secretary Kayleigh McEnany argued in response that the Democratic presidential candidate wants to "abolish the American dream."
Warren "vilifies successful people," says Jamie Dimon, CEO of JPMorgan Chase. Rubbish. Being a billionaire has nothing to do a with being successful in free market capitalism.Rubbish.
The Microsoft founder is on course to replace the Amazon CEO as the top billionaire after recent share price changes.
The Massachusetts senator and leading Democratic 2020 candidate is proposing a wealth tax on the richest households.
The French businessman helms the worlds largest luxury goods company.
The Fondation du Patrimoine, a private body that protects French heritage, said it intends to launch an international appeal for donations to help rebuild the cathedral.
The New York congresswoman was responding to a tweet about why psychopathic CEOs might be a good thing.
The world's billionaires grew their fortunes by $900 billion in 2018.
The world's richest people added $1.4 trillion to their fortunes last year as the gap continued to widen between the super-wealthy and everyone else.
A billionaire GOP megadonor has switched sides, and is now pledging to support the Democratic party.
Although Russia's elite may be holding onto their wealth despite U.S.-led efforts to target the economy, the working class and poorer communities may not be faring so well.
Forbes 2018 Rich List for Russia shows the wealthy elite nearly as rich as before Crimea sanctions.
The world's wealthiest billionaires made enough money in 2017 to end extreme poverty around the world seven times over, according to a new report.
Jeff Bezos also replaced Bill Gates as the world's richest man this year.
A group of more than 400 CEOs, doctors, lawyers and business owners is sending a letter to Capitol Hill that chastises the GOP for cutting taxes on the rich.
San Francisco billionaire Tom Steyer doesn't just want Donald Trump out: He wants national change, and he's recruiting a millennial army to fight for it.