How a Billionaire Is Using His Fortune to Reshape the Democratic Party

In the summer of 2023, gearing up for his bid for a second term, President Joe Biden gathered with a cadre of wealthy donors at a $7.5 million mansion in Greenwich, Connecticut. As the $25,000-a-seat fundraising dinner began, the president turned to thank his host: Stephen Mandel, a billionaire hedge fund manager and devoted Democratic donor.

“I wouldn’t be here, standing here as president of the United States, without a lot of you in this room,” Biden told them. Mandel and his wife, Susan, who have spent tens of millions supporting Democratic candidates over the past decade, were likely at the top of that list.

Three years later, Mandel, 70, is the largest bankroller of a nascent political machine promising to “redefine” the Democratic Party after its disastrous performance in the 2024 election. Rather than keeping to closed-door fundraising events, as he’s done in the past, Mandel has adopted a newly assertive approach as a mega-donor.

With $15 million in financial support from the Mandels, two recently launched organizations, Majority Democrats and the Bench, have made waves in Democratic primaries across the country. Their slate of chosen candidates, often challenging more progressive opponents, is bestowed with powerful campaign infrastructure — and Mandel’s money.

The network has helped deliver recent primary victories to candidates like James Talarico in Texas and Josh Turek in Iowa, among others across the country. All told, the hedge fund billionaire and his wife have contributed over $24 million so far this primary season, their largest spend in an election year to date.

Majority Democrats and the Bench profess to be focused on one goal: cultivating candidates, usually younger and free from strict ideological bounds, who “know how to win.”

But the nebulous rhetoric papers over a more ideologically driven operation. The network pledges to return the party to the more “moderate” middle, blaming the party’s failures on its progressive wing, rather than its donor class. To do so, Majority Democrats is backing more establishment-friendly candidates over progressives in a quest for a “new center.” In Michigan, for instance, the operation threw its weight behind state Sen. Mallory McMorrow over Bernie Sanders-backed candidate Abdul El-Sayed, who last week secured a narrow victory over Rep. Haley Stevens to win the Democratic nomination for the Senate race.

There could be more than just ideology driving the political machine. With some exceptions, many of the networks’ candidates are pushing to lightly regulate artificial intelligence, an industry in which Mandel’s hedge fund, Lone Pine Capital, is heavily invested.

Yet Mandel’s broader agenda remains elusive. The billionaire has continued to avoid the media spotlight and rarely makes public appearances. His small orbit of think tanks and political operations is oddly tight-lipped about what, precisely, his motivations are. Many insiders, including people who work at groups funded by Mandel, say they rarely speak to him, if they have done so at all.

The answers may be found in Mandel’s home state of Connecticut, which has served as a proving ground for his grander ambitions. There, the billionaire has shifted from passive donations to building a well-oiled political apparatus, fomenting upheaval and distrust among some lawmakers and advocates who spoke to The Lever. Similar concerns are already arising around Majority Democrats and the Bench.

“Mandel wants power and control, and all across the advocacy space he’s gotten it,” said one lawmaker in Connecticut. The legislator asked to speak anonymously, out of fear of reprisal from Mandel’s money machine.

Mandel’s aggressive approach will be put to the test in Connecticut’s primary election this Tuesday, where incumbent Rep. John Larson (D), a longtime union proponent backed by left-wing groups like the Working Families Party, is being challenged from the right by former Hartford mayor Luke Bronin. Bronin has amassed a sizable war chest, thanks to the Bench and other PACs that trace back to Mandel.

As it turns out, Bronin used to be on the payroll of a nonprofit funded by the billionaire, and his campaign’s policy stances reflect the network’s influence.

Whatever happens in Tuesday’s election, the field of Democratic candidates now headed into the general elections this November bears Mandel’s imprint.

The Mandels did not return The Lever’s requests for comment.

The Tiger Cub

Mandel grew up in Connecticut’s wealthy coastal suburbs, where his father ran a successful business buying and selling welding products. After doing a tour of elite education in the Northeast — Phillips Exeter Academy, followed by Dartmouth College and then Harvard University — he ultimately returned to Greenwich to build a career in finance.

For a time, while working at Goldman Sachs, Mandel took the train before dawn from Connecticut to the Wall Street firm’s austere offices in Manhattan. Mandel recalled in one rare interview that as he approached each morning, he thought to himself, “There are more smart people, good people in that building maybe than in another building in the United States.” (That was perhaps not completely true, he admitted, but “directionally true.”)

In 1990, Mandel departed Goldman for Tiger Management, a hedge fund led by the mercurial “wizard of Wall Street” Julian Robertson. Many of Robertson’s protégés — the “tiger cubs” — eventually departed Tiger to start their own hedge funds. Mandel was one of them; in 1997, he struck out on his own and founded the investment firm Lone Pine Capital. Over the next decades, he and Lone Pine proceeded to make quite a lot of money.

Lone Pine employs a high-conviction investment strategy concentrated in a handful of stocks — an approach Mandel learned from his mentor. The tiger-cub mindset would eventually come to define Mandel’s pattern of political giving: The portfolio can withstand losses as long as a few big bets pay off.

It’s an approach that’s paid off for his hedge fund, which today is heavily invested in artificial intelligence. This year alone, Lone Pine notched a 43 percent gain for investors in the first six months, trading far above the S&P 500’s 10 percent uptick during that same period.

In one podcast interview, Mandel described his approach to AI investing as identifying the “picks and shovels” for data center projects. “We know that running all these data centers… requires a huge amount of energy,” he explained. “So we’ve basically invested in everything from energy itself to producers of energy to all the way up to… the hyperscalers and basically the whole value chain.”

The Lever’s review of Lone Pine’s SEC disclosures shows that companies supplying the data center build-out make up roughly a third of Lone Pine’s overall stock portfolio. The Taiwan Semiconductor Manufacturing Company, a dominant chipmaker, was Lone Pine Capital’s single largest investment in 2025. Now the firm’s biggest investment is in the energy company Vistra, whose stock became a hot commodity after it signed power purchasing agreements with tech giants Meta and Amazon to supply their data centers’ massive energy demands.

The fund’s earnings from the AI sector have only added to Mandel’s soaring net worth, now an estimated $5 billion. The billionaire in turn pumps the money into political causes, as he’s done for decades.

The Coup

In 2001, Mandel established the Lone Pine Foundation and the Zoom Foundation, pledging $75 million worth of shares in Lone Pine to the latter. For the next two decades, these foundations were the center of Mandel’s charitable efforts, doling out millions of hedge fund money to the couple’s causes of choice.

Like with his political spending, Mandel launched these ventures alongside his wife, Susan. The couple met at Harvard Business School, and have three children. Although they operate in tandem, their interests diverge. “She kind of focuses on the environment,” Mandel has said, “And I focus largely on education.”

Education was Mandel’s focus from the beginning. He took a more traditional route to start, donating large sums to his alma maters. But by the mid-aughts, the billionaire had taken an interest in one issue in particular, which would become the core, and perhaps only, ideological throughline that can be traced through his decades of spending: charter schools.

At that time, charter schools were particularly prominent in the zeitgeist, hailed by many of their advocates as a panacea for troubled public school systems. Charters are typically publicly funded but are operated by private actors outside the oversight of public school systems, a model that has earned them opposition from unions and traditional champions of public education, and support from some families and education reformers. And as their critics point out, charters are known for their billionaire benefactors.

So when, in 2011, a disinvested Connecticut district ran into financial trouble, Mandel was quick to intervene.

That summer, state education officials in Connecticut took the unorthodox step of ousting the local school board in Bridgeport, Connecticut’s largest city. The 20,000-student district, already strapped for resources, was facing a multi-million-dollar budget shortfall.

It emerged that Mandel had for months been urging Connecticut state officials to take this drastic move. Though no specific figure was agreed upon, a consultant for his foundation implied that the Mandels could offer private funding for the school district — if the state moved ahead with a leadership shake-up.

Eventually, the state did just that. State officials ousted the school board and brought in one of the most prominent charter school advocates in the country, Paul Vallas, to lead the district — with his salary paid for by a fund set up by anonymous donors. (It remains unclear whether Mandel was involved with the fund, but his foundation has in the past donated generously to the Fairfield County charity that distributed the money.)

An enemy of teachers’ unions and vociferous proponent of market-based strategies in education, Vallas had previously razed the public school system in New Orleans and ushered in a new and polarizing system that revolved around charters. “He sold our schools off to the highest bidder,” critics say of Vallas’ record.

In Bridgeport, the courts later restored the school board leadership, finding that the ouster broke the law, and sent Vallas packing to Chicago (where he proceeded to launch several unsuccessful political campaigns). But the Bridgeport “coup” is still remembered bitterly by advocates for public education in Connecticut, and has poisoned Mandel’s reputation among some in the state.

Mandel would go on to spend millions more funding charter school advocacy groups, in Connecticut and nationally. He also served for a time on the board of Teach For America, a national nonprofit with a polarizing reputation in education, in part because of its close relationship with the charter school movement. Yet all the spending proved less fruitful than he had hoped, Mandel would later say. He began searching for a new way forward.

“The problem with education in this country is the system,” Mandel said in a 2021 interview. The path to positive change was clear, he continued: “It’s not pouring a lot more money. It can be done with the amount of money we spend now. But what is required is for both politics and — I’ll call it — embedded structures to change, and that’s really hard.”

It appears he set about forcing that change — starting in Connecticut.

The Puppet Master

Hartford’s Bond Ballroom, a swanky venue overlooking the Connecticut state Capitol, has long been a venue of choice for lobbyists and influence-peddlers hoping to sway state policy. For some years, a local lobbying shop threw an annual gala in the old hotel ballroom, a boozy event for state lawmakers that carefully exploited ethics loopholes to offer wine on the house.

The tradition had died out in recent years. But this spring, a new political heavyweight on the scene threw a gala for Connecticut’s power brokers that harkened back to the old days of hors d’oeuvres and Champagne. The mixer was staged by the Connecticut Project, a nonprofit organization founded by the Mandels in 2021.

Some guests described the event, the “Power in Policy” mixer, as a “massive influence effort” showcasing the political sway the group had amassed in just a couple of years over the state capital. Mandel, however, was nowhere to be found, according to multiple attendees. It was typical of the billionaire’s modus operandi as an absentee kingmaker.

The Connecticut Project today champions an “affordability” agenda as its raison d’être, with an emphasis on bread-and-butter issues. In the early days, however, the group launched with a generous endowment but no obvious north star.

“The Connecticut Project brings together people, ideas, and resources to build opportunity,” its website announces. Its mission: “Empower families, break down barriers, and create a brighter future.”

In Connecticut’s cash-strapped nonprofit world, the newcomer quickly attracted allies by cutting big checks. The organization began handing out generous grants to far-flung initiatives and trusted progressive organizations in the state — local YMCAs, homeless services organizations, education nonprofits, criminal justice reform groups — often with few strings attached.

These philanthropic efforts have earned the Mandels praise in the state. Eva Bermúdez Zimmerman, the coalition director of Child Care for CT, an advocacy group that receives financial support from the Connecticut Project, called the group a “phenomenal partner.”

“They consistently give the space and breath to focus on the movement and activate partners in the coalition,” she said.

By 2024, the organization’s annual spending on its various charitable endeavors and operational expenses had reached nearly $20 million. According to its most recent tax filings, the nonprofit disperses funding to over 70 organizations and projects in Connecticut, with grants often totaling in the hundreds of thousands.

Along with acting as a passive funder, the organization has established close ties with Connecticut’s power brokers, thanks to its in-house lobbying team. The group launched a 501(c)(4) advocacy arm, the Connecticut Project Action Fund, to lobby lawmakers and the state directly. In 2025, the action fund spent $680,000 on lobbying, according to the Connecticut Office of State Ethics, the second largest sum of any lobbying group in the state that year.

“Because of the number of staff they’ve been able to employ at the capital, Connecticut Project has definitely formed a lot of relationships with House and Senate leadership in the past few years and in the governor’s office,” said a Connecticut lawmaker, who, like several Connecticut insiders who spoke with The Lever, was granted anonymity to speak candidly.

Mandel’s critics in the advocacy world contend that the organization has given one billionaire couple outsize influence over the state’s nonprofit and political ecosystem. Another Connecticut lawmaker described the risk as a “dependency arc, where all of these organizations can’t operate without funding from him.”

“It’s like you’re sitting at the table with a bunch of groups and realize the Connecticut Project has their hand in the back of a lot of these organizations, almost like a puppet master,” said a political insider familiar with the organization.

Insiders say it’s unclear if the operation — and by proxy, Mandel — has an ulterior motive. “Everyone is sort of waiting for the shoe to drop,” said a different lawmaker, noting Mandel’s fidelity to charter schools.

Impact CT, the campaign arm of Mandel’s Connecticut operation, has already made its position on the issue clear.

Launched in the lead-up to the 2024 elections, the organization, which is funded by Mandel, is staffed by people with deep experience in the charter school movement. The operation is chaired by former New Haven mayor and charter school booster Toni Harp, and its primary consultant, Ruben Felipe, is the former executive director of the Connecticut Charter Schools Association.

Over the last two years, the group has supported several charter school advocates and others in long-shot primary challenges against progressives and pro-union incumbents in the state. This year, at least two candidates who were paid by Impact CT as part of its leadership training program went on to primary incumbent progressives, though neither made it on the ballot. The most prominent example was a failed primary bid this year by an education reform advocate against four-term state senator Matt Lesser after he vocally opposed a charter school in his district.

“I believe that the voters should get to decide who represents them, not wealthy special interests or Wall Street,” wrote Lesser in an email to The Lever.

Felipe told The Lever that dozens of people had gone through Impact CT’s training program, and the organization does not operate with strict ideological bounds.

“Any attempt to position the organization as anti-progressive is completely false,” Felipe said. “It’s an attempt to assassinate the character of the organization.”

The Connecticut Project’s own personnel moves haven’t put ideological concerns to rest, either. The organization is helmed by Garth Harries, a former superintendent of the New Haven public schools who oversaw a controversial effort to expand charter schools in the city.

Mandel’s imprimatur, therefore, comes with some risk. Some groups funded by the Connecticut Project have allegedly faced skepticism from lawmakers thanks to the billionaire’s money.

“These organizations he funds have not had an easy path,” said Bermúdez Zimmerman at Child Care for CT. “In the legislature, when you mention the Connecticut Project, there’s a good contingency of elected officials who do not play ball with them and are wary of them, because the roots are Steve Mandel.”

As the Connecticut Project’s ambitions grew, its policy priorities started to shift, as some had feared. After years of supporting and funding efforts to pass a child tax credit in Connecticut to alleviate child poverty, the Connecticut Project abruptly pulled back from the child tax credit coalition to focus on other priorities, according to multiple people familiar with the situation.

Instead, the Connecticut Project pushed for its own signature proposal in the most recent legislative session: a tax credit for renters to afford the rising cost of housing. The two policies, while theoretically compatible, are competing for slim state resources because of recent austerity measures imposed by Gov. Ned Lamont.

“People felt betrayed,” said one advocate with knowledge of the internal discussions.

The Connecticut Project denies that it left the coalition and says that the group still “ideally” backs both a child tax credit and a renters credit.

“We see them as complementary,” said Melvin Medina, vice president of advocacy at the Connecticut Project. “The cost of living has increased year over year over the last decade, and families are struggling to make ends meet.”

To child tax credit proponents, the group’s retreat from the coalition indicated a desire to plant a flag and put its own wins on the board, potentially to please their chief benefactor. That sharp-elbowed approach appeared to come at the expense of other causes.

When the legislature convened in January, the very first bill introduced into the state Senate with the support of the party leadership included the renters tax credit, a testament to the Connecticut Project’s influence. The child tax credit, which would be competing for the same funding, was put on the back burner.

Mask Off

At the start of this year, a buzzy new Democratic organization called the Bench made headlines with its call to, as The Washington Post put it, “change the Democratic Party from the inside.” The group pledged to do so by introducing “the next generation” of Democrats and steering those candidates to victory in their races through a deep donor network and well-connected D.C. consultants.

One of those fresh faces was former Hartford Mayor Luke Bronin, who’s vying for Connecticut’s first congressional district in Tuesday’s primary.

Mandel and his wife have together donated $4 million to the Bench, and another $11 million to its sister organization, Majority Democrats, which share staff and back many of the same candidates. The couple’s donations often are accompanied by those of other billionaires, including venture capitalist Tench Coxe, crypto CEO Michael Novogratz, and investor Mark Heising, all of whom have donated to multiple entities within the broader political network.

Through The Bench and its affiliates, the Mandel machine is working to boost Bronin — the biggest test yet of his political operation.

At 47, Bronin is relatively young, certainly compared to the septuagenarian he is taking on in the primary. He served in the military, deploying briefly to Afghanistan as an intelligence officer with the U.S. Navy, a fact that helps obscure his roots in New York’s wealthy Westchester County. Critics charge that he has seemingly few ideological commitments, offering up policy proposals with a populist sheen but light on substance.

His opponent, Rep. John Larson, 78, is an old-school progressive, backed by unions and a longtime champion for expanding Social Security. He boasts 14 terms in Congress, and has rejected all calls to step aside due to age (despite suffering a visible seizure while speaking on the House floor last year).

While certainly a member of the Democratic Party’s gerontocracy, Larson is also the kind of aging incumbent that the Mandels feel empowered to take on in Connecticut: A septuagenarian, but a progressive one.

The ideological fault lines of the primary race are stark. For this reason, the race has been described as a “mask off” moment for Mandel and the Bench by some observers who have tracked his spending.

“The Larson race is the key to understanding Mandel’s operation,” said Alex Lawson, the executive director of Social Security Works, a progressive advocacy group. “If it’s all just about electing ‘electable’ Democrats, then why would you be primarying John Larson from the right with Mandel’s hand-picked candidate and throwing everything they have at him?”

Bronin served two terms as the mayor of Hartford, but he has long harbored bigger ambitions. Before Bronin’s first mayoral term was up, he was already exploring a gubernatorial campaign (despite promising that he would not seek higher office before finishing out his first term). After all, Bronin’s peers had already achieved greater heights — at Oxford, he was housemates with Maryland Gov. Wes Moore (D), and he has long been close with former Transportation Secretary and former presidential candidate Pete Buttigieg.

Whether Mandel and Bronin have a personal relationship is unclear. But during his time in Hartford, Bronin appeared to support charter schools, Mandel’s pet issue, a matter that became contentious in the city at the time, pitting labor unions against business groups. During Bronin’s reelection campaign, the Hartford Teachers Union rescinded his endorsement because he accepted contributions from charter school advocates.

Once Bronin wrapped up his second term as mayor, he scored a cushy gig at the Mandel-funded Connecticut Project. In 2024 and 2025, as The American Prospect reported, the organization paid Bronin $237,000 for consulting services. During this time, Bronin co-authored a report on fiscal policy in Connecticut, but there’s no other public trace of his work there. (The nonprofit is “one of the most effective progressive policy organizations in the state,” Bronin said in response to criticism of the job.)

Bronin launched a bid for Congress in the summer of 2025. Support from Mandel’s political spending vehicles soon came flooding in.

Impact CT, for instance, has thrown its weight behind Bronin in the weeks before the Aug. 11 primary, spending over $400,000 on mailers, canvassing, and digital media in support of his candidacy.

Impact CT’s Felipe said that the group’s decision to support Bronin was not a directive from Mandel. The billionaire has made a commitment to allow Impact CT’s board and staff “to steer the ship,” Felipe said. “I can honestly, without exception, say there has never been a time that he said, ‘I want you guys to work on this race.’”

In July, a deep-pocketed Democrat-aligned super PAC called VoteVets launched a million-dollar ad campaign to boost Bronin’s candidacy, becoming his largest outside donor. Mandel, his wife, and Mandel-funded PACs like the Bench are together among the largest contributors to VoteVets this election cycle, having given over $500,000.

VoteVets has been active in several other races that Mandel’s network has taken an interest in, spending millions to support Iowa Senate candidate Turek (who is not a veteran) and New York congressional hopeful Cait Conley (who is). From the organization’s ads, which feature Bronin in uniform, it would be hard to tell that the group is part of a hedge fund billionaire’s sprawling political apparatus.

Over the course of the race, Bronin has staked out policy positions on the technology sector that fit neatly with his top donor’s financial interests. The Bronin campaign’s issues page on AI, titled “Getting the Balance Right with Artificial Intelligence,” takes a moderate path on data centers, acknowledging concerns while emphasizing that “it’s important that the United States continue leading the world in AI development.”

Such language is common across the ecosystem bankrolled by Mandel. In March, the Searchlight Institute, a policy think tank known to be funded by Mandel, released a white paper proposing to green-light and regulate data centers, rather than the moratoriums supported by the Democratic Party’s populist left. This policy proposal soon appeared on the campaign platforms of several high-profile Senate candidates supported by Mandel.

Still, Mandel’s candidates have a diversity of views on the issue; Jamie Ager, the Bench-endorsed Democratic candidate for North Carolina’s eleventh congressional seat, supports a short-term version of a data center moratorium.

The Bench rejected the idea that Mandel is controlling its operation.

“Any assertion that the candidates we support are defined by anything other than their values and what’s best for their constituents is wrong,” said Andrew Mamo, a spokesperson for the Bench. “We were founded precisely because big donors have too much power over what candidates do and say.”

That proposition could be put to the test as the Bench’s largest funder amasses his influence over the Democratic Party.