Democratic presidential candidate and former U.S. Vice President Joe Biden delivers remarks about White Nationalism during a campaign press conference on August 7, 2019 in Burlington, Iowa.

Billionaire and real estate magnate George Marcus is preparing to host former Vice President Joe Biden next month for a 2020 fundraising event.

Marcus, a billionaire megadonor who bundled more than $100,000 for Hillary Clinton in 2016, is expected to be the lead host at a lunch for Biden's return to San Francisco in the first week of October, according to people familiar with the matter.

Biden's allies have been prodding Marcus for months to open his doors to the campaign, these people added. Biden's campaign announced the candidate will be traveling to California on Oct. 3, but the press release did not give further details.

The fundraiser signifies that Marcus is looking to dedicate his expansive donor network to Biden's candidacy for president. Beyond his previous assistance to Clinton, Marcus also hosted a fundraiser that featured former President Barack Obama in 2014. The event was for the Democratic Congressional Campaign Committee at his mansion in Los Altos Hills.

Meanwhile, Biden has been trying to convince voters that he is not tied too tightly to wealthy donors. Biden has vowed that if he became president he would do away with President Donald Trump's tax cut that is often criticized for giving extra benefits to the ultra-rich.

Biden made an earlier fundraising swing through the Bay Area in June, when he was hosted by a former Twitter executive, among other prominent Democratic financiers. Biden finished the second quarter with a $21.5 million haul.

Marcus, who has a net worth of $1.5 billion, is the chairman of two publicly traded investment firms, Marcus & Millichap and Essex Property Trust. The companies have a combined market cap of $22 billion.

Marcus has been a prominent Democratic donor for the past decade. He was ranked 15th in 2018 among the top campaign contributors in the country, according to the nonpartisan Center for Responsive Politics. During last year's congressional midterm elections, he and his wife, Judith, combined to give more than $9 million to Democrats.

Biden is the only presidential candidate this cycle who has seen a contribution from Marcus, according to records. He wrote Biden a $2,800 check, the most a candidate can receive from a single donor, in May.

A spokesman for Biden declined to comment. While Marcus did not respond to a request for comment, he hinted in a May interview with the Nob Hill Gazette that he may eventually back Biden but hadn't made a decision at that time.

"Biden is someone I've known for a while. You're a bit more comfortable with people that you've known," Marcus said at the time. "He's mature and all that kind of stuff. I'm not saying he's my candidate, but there are a lot of very smart people who are running."

The event comes after Biden was under scrutiny for taking part in a fundraiser that was co-hosted by the co-founder of natural gas company Western LNG after pledging not to take contributions from fossil fuel executives. At similar events he's also pledged to take on the wealthy by eliminating the tax cut they received under Trump's administration.

"I think some of the tax cut made no sense. And by the way, I've got to level with you, because you've all been helpful to me. You know, I think we should reward work and not just wealth," Biden said at a fundraiser in Massachusetts on Saturday.