Joe Biden's recent string of primary victories appears to have satisfied wealthy donors who were discussing the creation of a super PAC aimed at pushing Sen. Bernie Sanders out of the race.

Instead, it appears they will hold off on engaging in an all-out assault on Sanders, a self-described democratic socialist who shuns wealthy donors.

As recently as last week, a handful of big money donors, some of whom work on Wall Street, were contemplating creating a political action committee whose sole purpose would be to try to knock Sanders out of the race, according to people with direct knowledge of the matter. They declined to be named as these conversations were deemed private.

The proposed goal was to raise at least $20 million to pay for ads and operational costs, these people noted. A super PAC allows organizers to raise and spend unlimited amounts.

The financiers' discussion last week ended in the decision to not move ahead because they believe Biden is on the path to capturing the nomination over Sanders, after a slew of key primary victories, these people added. They said that such a large-scale effort would be counterproductive, as it could embolden the Vermont lawmaker's argument that the establishment is trying to force him out of the race, they said.

Biden is leading Sanders in the primary delegate count after big wins in South Carolina, Super Tuesday states and other delegate-rich states such as Michigan, Missouri and Mississippi. Sanders has won contests in California, New Hampshire and Nevada. They are set to compete for delegates on Tuesday in Florida, Illinois, Arizona and Ohio. Biden is an overwhelming favorite to sweep all four.

There was a growing concern among the Democratic donor class prior to Biden's surge on Super Tuesday that Sanders was on his way to the nomination after picking up two early wins.

"It's Defcon 1," one of the organizers said at the time. Even after the Biden campaign picked up millions in new contributions in the wake of Super Tuesday, financiers continued to support the idea of forming a group to attack Sanders. Biden said then that his campaign raised over $22 million in the wake of victories in South Carolina and the ensuing primaries.

One of the donors who was being prodded by business executives to back the committee, and was interested in moving forward, is Bernard Schwartz, the CEO of BLS Investments, he said in a recent interview. Schwartz has been a donor to the pro-Biden super PAC Unite the Country.

"I think there is less concern over the last few days but we still have to put a lot of effort into fighting Bernie Sanders," Schwartz said just after Biden's success on Super Tuesday. The group's organizers were concerned that other candidates, particularly Sanders, would resist too long and take away resources from Biden, Schwartz said.

Schwartz was not the only donor who was contacted. Another Democratic megadonor on Wall Street, who declined to be named as he didn't want to disclose private conversations, heard from donors interested in the idea. This financier wasn't interested in being part of any anti-Bernie movements, he said, because he believed Biden could handle Sanders on his own.

Schwartz has been a vocal opponent of Sanders since the start of the election. His attempts to push Sanders out of the primary include privately reaching out to House Speaker Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y. Schwartz hoped they would come out to endorse any of the moderate candidates that, at the time, were still in the race.

Since then, all but Biden, Sanders and Rep. Tulsi Gabbard, D-Hawaii, who is barely racking up any support, have dropped out of the race.

There are other external groups targeting Sanders. Democratic Majority for Israel, a pro-Israel moderate group, has spent over $1.4 million against Sanders, according to the nonpartisan Center for Responsive Politics. Another organization, the Big Tent Project, has spent millions on digital ads and mailers against Sanders. It is a dark money group that does not have to disclose the names of its donors.

Money in politics has been a major theme on the campaign, particularly for Sanders, who routinely attacks the "billionaire class" and touts his support among small-dollar donors.

Sanders brought up the super PACs supporting Biden during Sunday's debate.

"Why don't you get rid of the super PAC that you have right now which is running very ugly, negative ads about me?" Sanders said.

Biden fired back, calling on Sanders to get rid of "the nine super PACs that you have." Though Biden did not list them, it appears the former vice president was taking aim at outside groups backing Sanders' candidacy for president, such as Our Revolution, a nonprofit dark money organization.