After expressing their deep fears over the prospect of Sens. Bernie Sanders or Elizabeth Warren winning the 2020 Democratic presidential nomination, Wall Street executives are opening their checkbooks to signal their favorite candidates as the primary race heats up.

"Some politicians go to wealthy people's homes and they sit around in a fancy living room, and people contribute thousands and thousands of dollars and they walk out with a few hundred thousand bucks. We don't do that."

—Sen. Bernie Sanders

CNBC reported Thursday that former Vice President Joe Biden, Sen. Kamala Harris (D-Calif.), and South Bend, Indiana Mayor Pete Buttigieg "combined to receive contributions during the second quarter from at least 15 bank executives from Goldman Sachs, JPMorgan Chase, Morgan Stanley, Citigroup, and Bank of America."

Buttigieg, who earlier this month hired a former Goldman Sachs executive as his national policy director, led all 2020 Democrats in fundraising in the second quarter of this year, raking in $24.8 million.

According to CNBC, the South Bend mayor "had some help from Wall Street in hitting that milestone."

"Richard Zinman, an executive director at J.P. Morgan, gave Buttigieg $2,000 in late April," CNBC reported. "James Mahoney, the head of global communications and public policy at Bank of America, gave the same amount to Buttigieg's 2020 campaign in June."

CNBC listed the names of other Wall Street financiers who doled out second-quarter campaign donations:

Former Goldman Sachs and Citigroup executive Robert Rubin has donated a total of $8,400 to Biden, Buttigieg, and Harris, CNBC reported. Rubin served as treasury secretary for former President Bill Clinton and economic adviser to former President Barack Obama.

Bank executives began contributing to 2020 Democrats in earnest in the second quarter of 2019, and they have some clear favorites. https://t.co/HrdNfpKSCQ — OpenSecrets.org (@OpenSecretsDC) July 26, 2019

Sen. Cory Booker (D-N.J.) also emerged as a favorite of the financial industry, according to the Washington Post, citing data from the first two quarters.

The New Jersey senator "leads the field in fundraising from the industry," the Post reported Friday, "pulling in $620,000 over the first half of the year."

By contrast, Sanders and Warren have touted their decision to eschew swanky big-dollar fundraisers with rich executives, relying primarily on small donations to fuel their presidential campaigns.

The two progressive senators are the only 2020 Democratic candidates to receive more than one million individual campaign donations.

Sanders hit the one-million donation mark in April; Warren reached that threshold on Friday.

"Powerful special interests and other campaigns are watching to see how ready we are to fight for big, structural change," Roger Lau, Warren's campaign manager, wrote in an email to supporters Friday. "And by hitting this first milestone, you're helping to show them that change is coming sooner than they think."

As Common Dreams reported earlier this month, Sanders raised $18 million from an average donation of $18 in the second quarter of 2019. Warren brought in $19 million from an average donation of $28.

During a "grassroots fundraiser" in Hollywood Thursday night, Sanders contrasted his approach to fundraising with that of much of the 2020 presidential field.

"Some politicians go to wealthy people's homes and they sit around in a fancy living room, and people contribute thousands and thousands of dollars and they walk out with a few hundred thousand bucks or whatever," Sanders said. "We don't do that."

"To me," said Sanders, "an $18 check or a $27 check from a working person is worth more than all the money in the world from millionaires."