U.S. Sen. Cory Booker (D-NJ) speaks at his 'Conversation with Cory' campaign event at the Nevada Partners Event Center on February 24, 2019 in North Las Vegas, Nevada. Booker is campaigning for the 2020 Democratic nomination for president.

Sen. Cory Booker, D-N.J., is dipping into his pool of financial industry donors as he looks for a fundraising edge in the early goings of the 2020 presidential race.

Investment executive Marc Spilker and businessman George Tsunis are among the growing number of financiers looking to help Booker at the start of the primary campaign, according to people with direct knowledge of the efforts.

Booker's connections to wealthy and influential donors could give his campaign an advantage over Democratic primary rivals who don't have similar relationships with players in the business world. Other candidates in the race, such as Sens. Elizabeth Warren and Bernie Sanders, have distanced themselves from big-money backers and groups while focusing on appealing to grassroots and small-dollar donors.

New Jersey rock legend Jon Bon Jovi and the state's governor, Phil Murphy, are also helping Booker raise funds. The pair hosted a fundraiser for Booker this past weekend. Murphy, who served as U.S. ambassador to Germany under President Barack Obama, is a former Goldman Sachs executive.

During the 2014 midterms, Booker received the most money from donors in the securities and investment industry, racking up a total of $2.2 million, according to the nonpartisan Center for Responsive Politics.

Booker is one of the few candidates who has not released fundraising data after he announced his run for president. He is known to be a prolific fundraiser and an appealing candidate for financial executives. He is one of the few Democratic 2020 candidates receiving support from a super PAC.

A spokeswoman for Booker declined to comment on his recent efforts to appeal to top party donors.

Spilker, a former 20-year veteran at Goldman Sachs who is now a founding member at private investment firm GPS Investment Partners, has indicated to friends that he's likely going to finance Booker's campaign during the primary, according to people familiar with the discussions. Spilker previously donated to Booker's Senate campaigns.

Between his tenure at Goldman and GPS Investment, Spilker was president of private equity firm Apollo Global Management, where he made $48 million in compensation his first year with the firm, a Securities and Exchange Commission filing shows.

Spilker did not return requests for comment.

Tsunis, a hotel magnate, has been reaching out to donors to set up a Booker fundraiser that will be hosted by fellow New Jersey Sen. Bob Menendez, a person familiar with the outreach explained on the condition of anonymity. Tsunis was once a top bundler for President Barack Obama and was later nominated to be the U.S. ambassador to Norway, although he eventually withdrew. In 2012, he helped raise at least $500,000 for Obama's re-election efforts, data from CRP shows.

"As I have been acting as a finance chair for Menendez's campaigns, it's not a far leap to say I'm behind this. I love Cory and happy to help Sen. Menendez help Cory. This is George helping Sen. Menendez help Cory Booker," Tsunis said in an interview with CNBC. "With me I'm trying to help every candidate at the beginning and eventually I am going to help the nominee," he added.

The Booker fundraiser, a lunch, is set for April 5 in New York, with tickets ranging from $1,000 to $2,800, according to an invitation first obtained by CNBC.

Tsunis supported Booker's Senate campaign in 2016, even though the lawmaker wasn't up for re-election. Tsunis has spent thousands of dollars to support the campaigns of other 2020 candidates and would-be candidates, including Sen. Kirsten Gillibrand's re-election and former Vice President Joe Biden's 2008 attempt at the White House.

Biden has not announced his candidacy, but people close to him say he's leaning toward a run. Tsunis later added in the interview that he will also back Biden if he gets into the race.

Another billionaire hedge-fund executive, who also raised funds for Obama but declined to be named for this article, told CNBC he gave $2,700 to Booker's 2020 campaign.

Meanwhile, Booker has the support of about 4 percent of Democratic primary voters, according to a survey done by Morning Consult. Ahead of him are Biden, Sanders, Warren, Sen. Kamala Harris and former Rep. Beto O'Rourke of Texas.

The interviews for the poll were collected from March 18, 2019, through March 24, 2019, and have a margin of error of plus or minus 1 percent.