After Biden's withdrawal from the presidential race, Kamala Harris experiences an increase in big money support.

• President Joe Biden's withdrawal from the race has led to a surge of big money donor support for Kamala Harris.
• Some of the party's top financiers withheld funds due to Biden's debate with Trump.

According to sources, Vice President Kamala Harris is receiving significant financial support from big money donors after President Joe Biden withdrew from the presidential race, thanks to the assistance of bundlers who have helped her in previous campaigns.

Immediately after Biden dropped out of the presidential race and endorsed Harris, those who helped raise money during her failed 2020 Democratic primary and successful 2016 Senate campaign began reaching out to wealthy donors, according to sources. These sources spoke to CNBC on the condition of anonymity to speak freely.

Some of the party's top financiers had decided not to contribute funds to Biden's campaign because they felt he did not perform well in his debate with Trump on June 27.

A longtime Wall Street executive, Marc Lasry, who helped raise money for Vice President Kamala Harris during her 2020 primary campaign against Biden, is now planning to assist her, according to a source with direct knowledge of the matter. Lasry also contributed to Biden's campaign when he defeated Trump in the 2020 election cycle.

Reid Hoffman, a venture capitalist, intends to contribute more money to support Harris' presidential campaign than he did to Biden's campaign against Trump during the 2024 election cycle, according to a source. Hoffman has already given at least $10 million to Biden's political action committees, as per FEC records.

Harris was endorsed by Hoffman in a social media post. Hoffman's spokeswoman refused to provide any comment.

Some donors were deleting the emailed invite for a fundraiser in the New York Hamptons region featuring Second Gentleman Doug Emhoff, which was planned by Harris' allies before Biden dropped out, out of frustration with Biden.

It is predicted that the Hamptons event next month will likely be fully sold out, with many donors stepping out of their comfort zones to support Harris, according to a source.

On Sunday, Alexander Soros, the son of Democratic megadonor George Soros, posted on social media that "it's time for us all to unite around Kamala Harris and defeat Donald Trump."

The support for Harris from major donors isn't consistent among all Democrats, indicating she needs to work harder to win their backing.

Stewart Bainum Jr., the chairman of Choice Hotels and a major Biden donor, stated on CNBC that he is not planning to assist Harris at the upcoming convention because he believes there should be a contest among potential nominees to lead the party. The Democratic National Convention is scheduled to occur in Chicago in August.

Another veteran Biden fundraiser suggested that a "mini primary" should take place in the weeks leading up to the convention for Harris and any other contenders who wish to challenge for the nomination.

For Harris, the presence of some donors quickly joining her campaign indicates that she could increase the over $95 million campaign fund she will manage after Biden exits the race.

The campaign submitted the new name "Harris for President" to the FEC and shared a donation link on her social media page.

According to Anna Massoglia, an investigations manager at OpenSecrets, Harris may obtain immediate access to the Biden campaign's $96 million donation fund.

Most people I've spoken with agree that she can use the funding, according to Massoglia, who shared this viewpoint in an interview with CNBC.

Some conservative election lawyers believe that Harris must first officially become the Democratic nominee in order to access the full campaign funds, although this view is held by a minority of lawyers.

The debate over whether Harris needs to be the official nominee is still ongoing, which means the funding access for her campaign and the donations of the Democratic National Committee and joint fundraising committees are still uncertain, according to Massoglia.

If Harris does not secure the Democratic nomination, the campaign may convert its funds into a PAC or another political committee to support the new nominee.

PACs are subject to higher advertising costs and cannot coordinate with candidates, according to Massoglia.

Refunding donors and asking them to contribute to another committee could result in donors not donating to the new campaign, according to Massoglia.