Mamdani retreated, a little bit. He praised Griffin for a donation to a 9/11 memorial for New York City police officers, and his press secretary declared that the Mayor wants all New Yorkers to succeed—including Griffin, “who is a major employer in our city.” But Griffin wasn’t finished exploiting the controversy. At a conference in Beverly Hills organized by his friend Michael Milken, the former junk-bond king, Griffin said that the pieds-à-terre video had put him “in harm’s way,” and noted that “the C.E.O. of UnitedHealthcare was killed just a few blocks from my house.” Griffin didn’t mention that his purchase of the Central Park South apartment was famous long before Mamdani’s video, or that he owns at least eleven residences worldwide—including adjoining co-ops on Park Avenue and four spreads in Florida. At the conference, Griffin said that Mamdani’s video was “triggering of the trauma I went through in Chicago,” where Citadel was originally headquartered. He’d had a noisy feud with liberal politicians in Illinois, increasingly over crime in Chicago, and this led him to move the headquarters of Citadel and Citadel Securities to Miami in 2022.

Several months before the Mamdani drama, I travelled to Miami and met with Griffin at a temporary office a few blocks from where he plans to build Citadel’s new headquarters, designed by the firm of the celebrity architect Lord Norman Foster. We sat down in the kind of white, sunlit, blandly expensive space where an aspiring trader might interview for a job. Griffin is very comfortable in such rooms—he estimates that he’s interviewed ten thousand people. Part of what makes Griffin different, however, is that he’s barely ever had to interview for a job himself. Lloyd Blankfein, the former C.E.O. of Goldman Sachs, who is a friend of Griffin’s, told me that he still can’t figure out “who mentored him—to whom he has a debt.” It’s a rare quality on Wall Street, which traces its heroes by the lineage of their strategies. Griffin started trading convertible bonds in his dorm room while studying at Harvard in the late eighties, then launched Citadel in Chicago in 1990, a year after graduating.

I asked Griffin to name which hedge-fund “ancestors” he’d modelled himself on. For seven seconds, he regarded me in silence. New Citadel employees learn not to fill in those pauses. Griffin’s blue eyes are unsettlingly bright. Colleagues debate, half in jest, about whether he lacks the normal need to blink.

Finally, he responded. “When I was in college, I wanted to be in private equity,” he said. He named one of the titans of that field: “Henry Kravis—that was the mission.” I pressed him to cite someone who had influenced him in the world of hedge funds—the investment firms that emerged in the nineteen-fifties with trading strategies designed to offer wealthy clients exclusivity, higher returns, and lower risks. Griffin dodged the question with a feeble joke. Early in his career, he said, whenever he told someone that he worked at a hedge fund, the response “was, literally, ‘Do you use shrubs or bushes?’ ”

There are many precursors Griffin could have cited. In the nineties, George Soros became famous for shorting the British pound. At the time, Soros, along with the financiers Julian Robertson and Michael Steinhardt, defined the public image of hedge-fund managers as investment wizards who made fortunes through huge bets, contrarian calls, iron stomachs, and a willingness to operate close to—or over—the regulatory line. Griffin became a leader of the next generation in part by aggressively automating college-level math to analyze trades. But he knows that he’s not a mathematical genius on the order of Jim Simons or David Shaw—pioneering “quants” who harnessed computing power to extract money from the markets. Nor did Griffin mention the other phylum of modern Wall Street, the descendants of Warren Buffett and Charlie Munger: the virtuosos of the long-term pick who identify stocks trading at sensible prices and let them compound for years.

Griffin has never pretended to be a radical innovator or a savant. His mission has always been different: to build finance businesses that update their strategies and infrastructure so relentlessly that they beat rivals not just today but over decades. Paradoxically, maintaining a consistent edge requires constant, unsentimental internal change—of processes, technology, and people. Citadel takes ideas that are just beginning to circulate and improves them, with math or technology or data that others haven’t thought to use. As Griffin once acknowledged, “If there are a thousand things that make Citadel special, there will be very few that are actually truly unique and bespoke to Citadel.” Before the millennium, for example, Citadel embraced the emerging technique of “event-driven” trading—strategies crafted to take advantage of major corporate news such as merger deals, bankruptcies, or regulations. In 2014, after many other traders had adopted event-driven trading, Citadel paused the practice.

“To keep your body from touching the same surface as previous bodies, we cover the table with this strip of paper that is narrower than all bodies.”

Cartoon by Asher Perlman

All this churn has been guided by Griffin’s fear that everything he’s built is fragile—the most impressive sandcastle on the beach. His longtime deputy, James Yeh, who is now retired, told me, “If you talk to a hundred executives, ninety per cent of them will tell you, ‘We’re never satisfied with what we’ve done before, we always want to do better, you can’t rest on your laurels, and you’d better constantly try to improve.’ But ninety-nine per cent of them don’t actually mean it. Ken actually means it.”

Given that Griffin lacks a signature trading or investing style, his achievements can feel both confounding and imitable. But nobody has duplicated his monetary success—or built two separate businesses that are so wildly profitable. Citadel’s fund now manages sixty-eight billion dollars, more than nineteen billion of which is Griffin’s and his colleagues’ own money. Although Griffin doesn’t directly run Citadel Securities, he is its non-executive chairman and owns at least seventy-five per cent of it. That business trades more than a hundred and seventy trillion dollars a year for institutional clients and retail investors. In 2025, it generated $12.2 billion in revenue on those trades and $5.4 billion in net income. Bloomberg estimates that Citadel Securities accounts for nearly half of Griffin’s net worth, which has tripled in the past six years. (Being the top man on Wall Street makes him only the world’s thirty-seventh-richest person, according to Forbes—well behind the six tech giants who top the chart.)

In an era in which income inequality is a source of increasing political and social concern, Griffin is an unabashed big spender. For him, half a billion dollars is a basic unit of currency. He spent that much for twenty-seven acres in Palm Beach; for the joint purchase of a Jackson Pollock and a Willem de Kooning; in gifts to Harvard; and in political contributions, mostly to conservative candidates. He dropped a mere forty-five million on a stegosaurus skeleton, called Apex, which is now on loan to the American Museum of Natural History (though “the dream,” Griffin told me, “is one day she’ll be in Miami”).

Griffin may decide that running for political office is a bet he’s not willing to make: a Harvard man with a hedge fund and a house on the French Riviera might unite people across parties in distaste. Then again, he has the cunning and the means to update his image, and he remains ambitious. He told me, “I take great joy in problem-solving. If there was a moment that came to pass where those skills would be of crucial importance for our country, of course I would look to be involved.”

Kenneth Griffin was born in Daytona Beach, Florida, in 1968. His mother, Cathy, was just two years out of high school in Libertyville, Illinois, where she had been the student-council president. Ken was the first of three children. Cathy, a housewife, had contemplated becoming a teacher, Griffin told me. “She changed the mobile over my crib every week when I was a baby,” he said. “She read somewhere you’d be more curious.” (Griffin suggested to me that he’d never lost his curiosity. He also added this flourish: “Maybe I never grew up.”)

Griffin’s father, Don, worked in the space program at General Electric. Job offers led him and the family to suburban Milwaukee and Midland, Texas; finally, they relocated to Boca Raton, Florida, where he became the C.F.O. of a roof-tile manufacturer. Griffin recently addressed students at Boca Raton Community High School, his alma mater, and recounted that he’d learned to code after negotiating with his parents for an I.B.M. personal computer. In high school, he took part in high-achiever activities—math team, a community-service group—but he was also an entrepreneur, selling software from various venders to students and teachers.

At college, Griffin could code as well as many computer-science majors, but he studied economics and government, writing a thesis on shareholder returns in corporate takeovers. He graduated in three years, using A.P. credits from high school—an unusual move at Harvard, though most students there could have done the same. He was dating a young woman from Boca, Katherine Weingartt; they married when he was twenty-two and divorced four years later. (Griffin is now twice divorced and unmarried. He has three children.)

Around the time Griffin was in college, three books were published which became the modern Wall Street canon—“Liar’s Poker,” by Michael Lewis; “Barbarians at the Gate,” by Bryan Burrough and John Helyar; and “The Bonfire of the Vanities,” by Tom Wolfe. These books could be gimlet-eyed about the follies of finance, but they also glamorized new paths to riches, from leveraged buyouts to bond securitization. According to Alex Slusky, a college friend of Griffin’s and later a private-equity investor, most aspiring financiers at Harvard “just wanted a job.” Griffin had a different plan: “To build something of significance in finance using technology.”

He started trading in 1986, and, he told me, made five thousand dollars on one transaction involving Home Shopping Network options. But he said it bothered him that the market maker who bought the options, though his profits were relatively small, had a much higher “quality of earnings”: whereas Griffin was taking risky bets, the market maker was generating a reliable cash flow. Griffin’s frustration led him to try to find a way to achieve higher-quality earnings himself. At the Harvard Business School library, he taught himself derivatives pricing and trading theory, and by 1989 he’d settled on convertible arbitrage as his method of choice—buying a company bond that could be converted to stock while simultaneously shorting the company’s stock. At the time, this strategy was being pursued by only a few banks and about a dozen hedge funds, even though you could do the math with pen and paper.

Griffin called up First Boston, an investment bank, and asked a salesperson how it handled convertible arbitrage. The salesperson, Griffin remembers, said, “We don’t do this with any customers. We do this with the firm’s money.” To Griffin, “that was a light-switch-on moment.” He got Harvard’s permission to install a satellite dish atop his dormitory, Cabot House, so that his I.B.M. could get real-time trading data. Touting himself as part of a new money-management firm, he raised more than a million dollars, from a Palm Beach retiree, his grandmother, and others. He programmed his computer to price equity-linked securities, allowing him to assess value better than many professionals. And yet, the origin of Griffin’s empire was neither the satellite dish nor the coding but, rather, the idea of seeking out higher-quality earnings not yet being widely pursued.

Griffin founded Citadel in Chicago because he’d received an investment from Glenwood, a firm that staked small hedge funds, and he liked Glenwood’s gruff Chicago-based partner, Frank Meyer. Hedge funds were then in their second of three Cambrian explosions; according to one estimate, a thousand new funds formed following the 1987 stock-market crash. Hedge funds are most attractive to investors when the over-all market performs poorly, as bruised investors seek ways to protect themselves against another crash by putting their money in the hands of people supposedly expert at managing risk.

Meyer advised Griffin to make two moves that were cheeky for a new fund managing only four and a half million dollars: first, adopt multiple investment strategies; second, charge “pass-through” fees to investors, requiring them to cover Citadel’s expenses as incurred, rather than having them pay the traditional fixed management fee of two per cent. This allowed Citadel to spend more aggressively on people and technology in pursuit of higher returns. Griffin’s carried-interest take of the fund’s annual gains remained more than twenty per cent.

The early Citadel had an improvised feel. With little money or reputation, Griffin often hired inexperienced people who had impressed him in interviews, including Yeh, a graduate student in theoretical physics, and Beeson, a cop’s son who had studied accounting on a scholarship at DePaul. (Beeson became Citadel’s C.O.O. in 2008.) The firm was a nerdy, all-hours place. Griffin himself had coded a trading model for employees to use on Sun workstations. By Yeh’s estimate, the math used in the model was five years ahead of the market. The I.T. staff made up more than a quarter of the head count. Julio DePietro, an early hire who later became a partner, and who helped come up with the name Citadel, told me that traders sometimes rewarded themselves at the end of the day with “teeny Pounders,” a McDonald’s Quarter Pounder cut into fourths.

“Behold Vorgar, destroyer of lands, reaper of death, bachelor of fine arts!”

Cartoon by Ellis Rosen

Griffin obsessively monitored his competitors’ moves. Yeh recalled to me that, at one point, Griffin theatrically presented him with a piece of paper bearing a number: the profit David Shaw’s firm had made through a new technique called statistical arbitrage, or stat arb. It was a bonanza.

“What the hell is stat arb?” Yeh asked.

“I’m not really sure,” Griffin admitted. But, he continued, it involved “numbers and formulas and computers,” all of which were part of Yeh’s physics background. Griffin told Yeh to choose one other colleague for a new team that would learn by doing. Citadel started trading stat arb about six months later.

“I do enjoy understanding what systems we need to build,” Griffin told me. “I am willing to get my hands dirty with all kinds of details that in some sense would often be viewed as not belonging on the radar of a C.E.O.” At one point, Griffin moved his office away from the trading desk, but he kept going back over to look at traders’ screens. An early employee told me, “We used to joke—is the dragon in the cave, or is he out?”

Citadel has never publicly codified how it achieves “alpha”—outperforming the market. But my conversations with Griffin and twenty-eight of his current and former employees revealed that they had consistent tenets. The output of Citadel’s factory is alpha. Every aspect of the factory must be constantly improved, and to accomplish this everyone must forage for information. The purpose of every improvement is to minimize unknown risk so that Citadel can maximize intentional risk. The biggest risk of all is complacency. The objective is not just profit but victory over rivals.

An ongoing challenge is that every idea that beats an efficient market eventually becomes stale. You can scour the world for better weather forecasts to make bets on the cold snaps that affect natural-gas prices, but if you are successful other funds will start doing the same. Griffin sponges up intel wherever he can find it. A former underling told me that Griffin, after reading a PCMag article about the differences between Advanced Micro Devices and Intel chips, asked why the underling wasn’t recommending A.M.D. chips for the company’s servers. Griffin is still so up to date on technological wonkery that he is Citadel’s de-facto chief technology officer.

The goal at Citadel is not to be right all the time; it is to be consistently right most of the time. (The fund’s best portfolio managers beat the market on only about fifty-four per cent of their trades.) As Alec Litowitz, an early Citadel partner, told me, “It’s not about a portfolio, it’s about a business that can re-create great portfolios again and again.”

Citadel, built on an economic law of diversification to reduce over-all risk, takes as many uncorrelated risks as it can. That way, no one event can capsize the fund. Portfolio managers and analysts are asked to manage more money than at many rivals, and cannot stop aggressively trading. (Elsewhere, a trader who has achieved strong returns by Thanksgiving may try to quietly lock in a year-end bonus by taking on little new risk in the remaining weeks.) Unlike at some other funds, Citadel traders are required to maximize their “idio”—the idiosyncratic element of every trade. An average Citadel equity-portfolio manager turns over his portfolio ten times per year.

Griffin pushes Citadel to interrogate its methods and break industry precedent. Traditionally, for example, a fund relies on prime brokers at an investment bank to settle the exchange of securities for cash. Early in Citadel’s history, it cut out these middlemen; the speed that resulted from “self-clearing” its trades gave it a pivotal advantage in the digital era.

Citadel’s high pass-through fees, which have sometimes reached twelve per cent, help pay for top traders and technology, but they also represent a risk themselves—such spending can destroy a hedge fund if net returns are too low. (A large rival, Jain Global, recently foundered, partly for this reason: last year, it generated gross returns in the mid-teens but net returns of less than four per cent, disappointing investors.) Citadel borrows a ton of money—currently, it is financing investment assets of more than three hundred billion dollars—and that helps offset this risk. If a hedge fund can generate five-per-cent returns on a seven-dollar trade, and six of those dollars were borrowed, then the return on the one “equity” dollar it invested will be thirty-five per cent, before the fund covers the interest on its debt and pays other expenses. However, this level of leverage has risks, too: with a modest six-per-cent loss you may suddenly need cash to satisfy your lenders. Such pinches have been toppling financial firms for decades.

Griffin doesn’t worry much about Citadel’s leverage—he feels the company knows how to manage it. But what he hates is “when we make careless mistakes” because employees become too cocky about the firm’s size and success. A former executive said that “Ken’s way” of combatting suboptimal performance was “some amount of turnover,” adding, “There needed to be some fear in the organization.”

In 1994, the bond market crashed, and Citadel had its first down year, losing 4.3 per cent. One employee at the time recalled that the fund dismissed seven of its recently hired traders. A few years later, in a precocious move—he was not yet thirty—Griffin locked up the fund’s capital so that investors couldn’t ask for it back immediately during periods of market turmoil. In 1998, Citadel took advantage of one such period by buying when other firms’ capital was less secure. That year, it reached a billion dollars in assets under management. By 2004, it had ten billion. Convert arb, Griffin’s dorm-room strategy, remained Citadel’s profit center for most of its first decade. Yet the fund regularly booted out traders and set up new teams to pursue fresh trading ideas, eventually focussing on five areas: commodities, equities, quant, fixed income and macro, and credit and converts. Most famously, Citadel spearheaded an approach to equity investing that Wall Street calls “pod shops.” In each largely independent “pod,” a portfolio manager may lead three to nine analysts and associates, with each analyst responsible for about fifty stocks in a specific industry. Citadel expects the traders to be the biggest experts on Wall Street on those stocks, and to know how rivals are positioned. Pods that flourish are given more money to invest, allowing Citadel to take on more risk. Pods that flounder are eventually shuttered.

Citadel also became a “grave dancer”—taking over the assets of failing hedge funds or other businesses. Griffin flew sixteen people to Houston on a chartered jet to interview hundreds of Enron’s employees during that company’s demise. Citadel also added new businesses not conventionally part of a hedge fund, including a technology platform and a derivatives market maker that was the precursor of Citadel Securities. Griffin saw that the digital-trading era had opened up an opportunity for a firm like Citadel, which had ample money to invest in hardware and had spent years improving algorithms to minimize risk and accelerate trades.

Citadel was successful but borderline obnoxious. The firm, even more than its peers, cultivated a culture so secretive that employees were not allowed to let any outsider know what they did at work. If Griffin suspected that an employee was sharing proprietary information, he might ask a Citadel lawyer to conduct an investigation, which could include reviewing employees’ e-mails. He retained an odd intensity. A former employee said, “When Ken didn’t want to make a decision, he’d stare into space for an extended period of time while he was processing.” In 2005, the Times printed a leaked e-mail to Griffin from Dan Loeb, the manager of a different hedge fund, that snarled at the “gulag” Griffin had created: “You are surrounded by sycophants but even you must know that the people who work for you despise and resent you.”

Many competitors on Wall Street were thus gleeful when Citadel’s main fund fell by fifty-five per cent during the 2008 global financial crisis. CNBC parked a truck outside the firm’s headquarters in order to film its death. Griffin told me that Citadel would have collapsed had Morgan Stanley failed, as that would have ignited more panicked selling. Citadel’s assets plummeted in value not because it had excessive exposure to the dubious mortgage-backed securities at the root of the financial crisis but because it had underestimated how its own “safer” and purposely uncorrelated bets would fare in a crisis when strange things happened and nearly everything became correlated. The Securities and Exchange Commission, for instance, banned short selling on certain financial stocks, a move that upset Citadel’s efforts to hedge some securities. Many unshortable companies stopped paying dividends, and Citadel trades that had involved paying for those dividends up front piled up losses.

But Citadel survived the crash, in part because of the unusual trading and capital systems Griffin had built. During the crisis, for instance, Citadel’s self-clearing of trades allowed it to know exactly where it stood financially every minute. Still, Griffin found the moment humbling. He and several partners had to put half a billion dollars into the fund, in part to retain employees who hadn’t lost money. He apologized to investors for suspending their ability to take money out of the fund. Citadel would not be able to receive a fifth of future profits again until the fund hit the “high-water mark” that it had achieved before the crash. But Griffin didn’t shut down the fund and start over. As Warren Buffett once complained, other hedge-fund partners were notorious for making this move, “so that they could immediately participate in future profits without having to overcome their past losses.”

During Citadel’s reboot, investors started asking pointed questions about the fund’s side businesses, especially Citadel Securities, which officially became a separate entity in 2012. The extent of that separation is still the source of considerable speculation on Wall Street. Even sophisticated players told me that Griffin’s hedge fund must benefit from Citadel Securities’ trading data, and that Citadel Securities must profit from the hedge fund’s trading volumes. Citadel executives brusquely dismiss the idea that anything shady is going on. Jim Esposito, Citadel Securities’ president, told me that the market maker does not have Citadel as a client. And, because Griffin remains the C.E.O. of the hedge fund, there are limits to what he can know about Citadel Securities’ business—even though he’s on the board and owns most of it.

Yet suspicion endures, in part because Citadel Securities isn’t just a passive taker of orders to buy and sell. A decade ago, it jumped ahead of the competition in “high-frequency trading”—a term it coined—by spending vast sums to use fibre-optic cables laid between Chicago and New Jersey, allowing for faster communication between stock and option exchanges in those locations. The company used this speed advantage (and, later, similar ones) to profit from infinitesimally brief pricing differences between exchanges, all while fulfilling clients’ orders to buy and sell on those exchanges. Citadel Securities told certain clients that it was getting them the best price when executing those trades; from 2007 to 2010, the firm didn’t actually do so about three per cent of the time, and it ended up having to pay the S.E.C. a $22.6-million fine. By 2014, high-frequency trading in general had become controversial. Senator Elizabeth Warren called it market manipulation. Michael Lewis, in his book “Flash Boys,” caustically observed, “The U.S. stock market was now a class system, rooted in speed, of haves and have-nots. The haves paid for nanoseconds; the have-nots had no idea that a nanosecond had value.” The criticism died down only after shaving off nanoseconds became widespread, making the strategy less profitable.

More recently, Citadel Securities has been attacked by Warren and others for a practice called “payment for order flow.” Citadel Securities pays about a billion dollars a year to retail brokers such as Robinhood for the privilege of fulfilling amateur investors’ orders—to buy everything from common shares of Nvidia to stock options. Matching a buyer to the seller of those securities generates tiny margins but is immensely profitable in the aggregate. Robinhood uses P.F.O.F. “rebates” to provide its customers with commission-free trading at spreads—the gap between what the buyer will pay and what the seller will accept—that are microscopic by historical standards. Yet the Wall Street watchdog Better Markets calls P.F.O.F. a “kickback,” and argues that companies like Citadel Securities, by subsidizing commission-free trading, encourages inexperienced people to trade with “excessive frequency and in excessively risky products.”

Griffin is unswayed by such arguments. He told me that the “explosion in trading volumes” was a good thing, because people were less prone to stick to bad bets. “When the cost to change your mind goes down profoundly, you’re more willing to change your mind,” he said. But forty per cent of the options trading for retail clients by Citadel Securities is for “zero-day contracts”—almost comically risky trades that are all or nothing at the end of each day. Europe plans to ban P.F.O.F. at the end of this month.

Impulsive trading, of course, led to the 2021 GameStop “meme stock” bubble, when the company’s stock soared largely because of retail trading on Robinhood. Citadel ended up making a grave-dancer investment in Melvin Capital, a hedge fund that had shorted GameStop, to capitalize on Melvin’s distress. In “Dumb Money,” a film about meme stocks, Nick Offerman plays Griffin as a smug cyborg whose tennis games keep getting rudely interrupted by the crisis. Griffin’s lawyer reportedly sent threatening letters to the filmmakers.

By the start of 2012, Citadel had passed its pre-crash high-water mark, and by 2015 it had twenty-five billion dollars under management. But the next three years reeked of alpha decay—the firm’s average yearly gain slumped from eighteen per cent to nine. Such decline is almost an expected outcome for a firm of Citadel’s size and age, but Griffin was intent on defying the trend. He started directly running the commodities-trading division, which had a setback in 2014, when the polar vortex walloped a large natural-gas trade that Citadel had made. Griffin sat alongside mid-level employees, crunching numbers. (That was “a lot of Ken,” one employee later joked.) In 2017, Griffin hired an Australian named Sebastian Barrack to ramp up the commodities business. The firm hired hundreds of people, including hydrologists and other experts in very specific parts of the weather. And it invested heavily in technology to, for example, better shape sensor and satellite readings of the physical world into forecastable form. To critics of Wall Street, it might seem obscene that leading weather experts, presumably trained to help mitigate the destruction from, say, a hurricane, were lured away to help Citadel profit off one. But Citadel’s commodities division became enormously successful. It made more than ten billion dollars in 2022 and 2023 alone, in large part from trading European natural gas, exploiting a huge price spike that occurred after Russia invaded Ukraine.

A former Citadel portfolio manager said of such overhauls, “The next incarnation of what gets built is better than what was there before, and that’s always the case.” The downside: “a highway wreck of human bodies.” Almost every former employee I spoke to had stories about turnover. One had five bosses in five years; another kept a “Book of Souls” listing the fifty colleagues who had left his small trading unit in six years. Yet another moved to Chicago only to see his boss’s boss be immediately fired, and then his boss fired. Amid the bloodshed, a source told me, the reading of internal e-mails continued, if Griffin thought someone had lied to him or stolen information. (A Citadel spokesperson said of its firings, “We have deliberately built a high-performance culture.”)

It may comfort outsiders to know that at least some pain comes with hedge-fund jobs that pay millions of dollars to people who push buttons to buy and sell. Citadel is proud not to have a touchy-feely atmosphere. Jim Esposito told me that Griffin expects efficient communication, adding, “This is not a place where a long windup is well received.” A former business leader recalled that meetings with Griffin “could turn dark very quickly” if someone tried to “gild the lily.” Two ex-employees said that their children still remind them of how they were when they worked at Citadel: irritable, exhausted, often absent.

And yet, as unrelenting as Griffin may be when you work for him, employees at least know where he stands. He sometimes yells, but his anger is more cold than hot. At the giant hedge fund Bridgewater, the culture has been performatively sadistic; its former leader, Ray Dalio, reportedly once mandated that employees watch a video of a pregnant manager crying after he’d called her a “dumb shit.” I heard only two Citadel stories that bordered on the cruel. Griffin scheduled a regular Friday-afternoon meeting with an underperforming executive, who never knew if the meeting would last fifteen minutes or four hours; after three months or so of this humiliation, he was canned. And Griffin ordered the head of one desk to fire two of four hires, all recent college graduates—any two—because, a source told me, “That should be the standard.”

Ex-employees tend to have little resentment about their time at Citadel. “It was a gift to be there and a gift to leave,” one told me. New employees are given immediate responsibility, and about half of the portfolio managers have risen from more junior roles. Mid-level workers get to execute major projects, with no expenses spared. One person remembers musing during his first week about buying a fleet of new computer servers, and being told to purchase them right away. Griffin explained why Citadel offered employees such license. New hires, he told me, “may be fantastic salespeople, they may be outstanding investment professionals. But they’re actually not entrepreneurs. And, in building businesses, you learn over time who your entrepreneurs are.” Griffin has even relaxed the office culture a bit. Halloween is now a big day there, and he dresses up: Iron Man, Buzz Lightyear, a velociraptor.

“Sometimes bickering a little can help give you a sense of how it would feel to live here.”

Cartoon by Liam Francis Walsh

Employees who thrive at Citadel have also shared in the hedge fund’s gains, which have been colossal since 2019. Griffin said of that period, “One of the key advantages that our team had is that we actually saw the softballs.” (Asked to cite examples, he told me about the “enormous spreads” on Wells Fargo bonds at the height of the pandemic.) “We put those balls out of the park, and we did it day after day after day after day. I mean, just—” He chuckled. “There were days you looked at the profits and losses, and you’re, like, ‘This is not possible.’ ”

Citadel has delivered a nineteen-per-cent average annual net gain since 1990, with only two years in which it lost money. From 2019 to 2024, that gain averaged twenty-three per cent, with no down years. (The S. & P. 500 rose by an average of nineteen per cent during the same period.) In our meeting, Griffin characterized this as “one of the great runs in the history of finance.” Pasted on Citadel’s elevator doors is a title awarded by L.C.H., a fund that publishes annual rankings of the industry: “The most profitable hedge fund of all time.”

This was also a golden period for Citadel Securities, which in 2022 was valued at twenty-two billion dollars, and is now likely worth much more. The market maker now handles about a quarter of all U.S. equity volumes and some thirty per cent of U.S. equity options. It is also a leading player in floor trading and other services that the big investment banks dismissed as being beneath them. A competitor told me that the banks aren’t sure how they can compete with Citadel Securities’ economies of scale and technology. Griffin, of course, is thrilled that the company, whose C.E.O. is Peng Zhao, is so dominant. “I’m not going to disrupt that!” he said.

During a talk with students at Stanford’s business school last April, Griffin said, “I’m so blessed to have been born in this country.” He continued, “I would like to believe that I will—I will have done my fair share to make this the greatest nation in the world.”

Griffin proposed that his legacy was still being built from “other wins, both for Citadel and, more importantly, for America.” He likes to talk about three social benefits of his businesses. The first is the easiest to accept: the extraordinary performance of his hedge fund has enriched his investors, which include five of the eight Ivy League schools. A Citadel allocation is so coveted that the company now chooses whether, and how much, clients can invest—an inversion of the usual dynamic. Moreover, Citadel is an outlier in an industry that disappoints investors with surprising regularity. Since 2010, according to data from the research firm H.F.R., hedge funds as a whole have delivered a mere 5.6-per-cent annual gain and have lost money on average every four years. (This hasn’t stopped generations of hedge-fund managers from getting wealthy off of third-rate performances.)

The other two benefits that Griffin cites are more debatable. At a talk at Goldman Sachs last year, he boasted that Citadel Securities and other market makers have “radically increased the number of families that participate in the equities market.” He added, “We democratized finance.” The owners of sports-betting apps could make a similar claim, though they wouldn’t pretend to be so high-minded. Moreover, Griffin’s embrace of the Robinhood revolution feels out of synch with skepticism he expressed to me about a current industry push to make it easier for the public to invest in hedge funds and private-equity funds. Retail investors, Griffin said, are “not best equipped to make a thoughtful or reasoned decision” on risk and rewards when it comes to these funds. Such investors, not coincidentally, are also not people whose money Griffin needs.

The third benefit, as Griffin said to a group of Citadel interns last year, is that, “in the history of modern markets, no firm has impacted the markets as much as Citadel Securities has, both in the liquidity of the markets and the cost to trade.” On Wall Street, as for an antiquarian bookseller, intermediaries tend to make the most money when the job is most difficult. In finance, this might mean a trade when buyers or sellers are scarce, or unable to transact at the same time. Citadel Securities, by making millions of trades per day for its own profit-seeking and to fulfill customer orders, has eliminated inefficiencies by always having the liquidity necessary to buy or sell in large volumes.

Yet Griffin’s businesses are not doing these things as a public service—that’s a side effect. And Citadel isn’t an investment firm that provides capital to companies that build steel factories or fast-casual restaurants. Moreover, the liquidity provided by Citadel and Citadel Securities is not an unalloyed good. More than forty years ago, Warren Buffett warned that “hyperactive equity markets subvert rational capital allocation and act as pie shrinkers.” Public companies, he explained, make nearsighted corporate decisions in response to “casino-type markets and hair-trigger investment management.” Investors, instead of providing capital to companies that want to grow their businesses, pursue high-fee trading strategies—which, Buffett points out, almost never do better than the market. More broadly, the financial rewards of hedge funds lure talented people away from other meaningful endeavors. An uneasy sadness came over me when a Citadel Securities executive told me that the company targets “the best and brightest minds on the planet.” The firm’s publicists proudly asked me if I’d seen a story they’d planted in the press about a coding prodigy, Kairan Quazi, who’d joined the company at the age of sixteen. Quazi told Business Insider, “At Citadel Securities, I’ll be able to see measurable impact in days, not months or years like many research environments.” The article, decorously, didn’t mention making money.

In Miami, I asked Griffin if the profitability of the finance industry was justified. “I think it’s, it’s—” he said, falling silent for ten seconds. He then told me about a friend who was trying to make housing more affordable by reducing the cost of title insurance. He detoured into a story about the likelihood of a family in Mississippi losing all its money in a crypto heist—the implication was that stock trading was better than that. Finally, he touched on the fortune that Citadel makes through its trading decisions. “The question is, are the fees that people pay to have research done, are they fair?” He paused again, and gave his final answer: “There is a market.”

If you wanted to convince yourself that billionaires shouldn’t exist, you could do worse than fly to Florida, drive across a bridge to Palm Beach Island, take a right at Mar-a-Lago, and drive five hundred yards to a twenty-seven-acre construction project. Starting more than a decade ago, Griffin has spent four hundred and fifty million dollars to buy the land and level a few incumbent mansions, one of which was eighteen thousand square feet. The New York Post likes to say that the planned residential compound will be “the most expensive home on earth.”

Griffin’s real-estate portfolio includes properties in Aspen, Hawaii, Montana, Southampton, Saint-Tropez, and London; three in South Florida (Palm Beach, Coconut Grove, and Star Island); and the apartments in New York City. The total cost of these holdings, one and a half billion dollars, doesn’t include construction expenses at the residences, some of which are not yet built, or the private planes and the yacht where Griffin could also rest his head. The acquisitions keep coming: near his Star Island property, he recently purchased land where he plans to construct berths for six yachts, thirty-seven thousand square feet of buildings, and pickleball and padel courts.

I asked Griffin if the public’s fascination with his real-estate holdings irritated him. “It doesn’t impact my life,” he said. “If we’re a nation obsessed with homeownership, it’s almost good, right? We still believe in America. We want to buy homes in America. We want to have the American Dream. God bless.”

He also told me that, after the 2008 crash, in which he “lost virtually everything in sixteen weeks,” he made a decision “that some portion of my net worth would be in non-financial assets.” He admitted that the Palm Beach property was “a bit untraditional” as an investment compared with, say, owning an entire condo building. But his family gets to enjoy the place all by themselves.

There will initially be two houses on the Palm Beach lot: a main one (eighteen thousand square feet) and a tidy guest house (seven thousand square feet). The main house, a serene succession of rooms with floor-to-ceiling windows, will resemble a wellness resort. That’s for his mother. Griffin plans to erect other buildings on the property for himself. “I love design, I love architecture,” he told me. Many of the floors in his mother’s house will be laid with “rift-cut” eight-inch-wide white-oak planks, the manufacturing of which was so arcane that it required Amish craftsmen. The cost was extremely high, the visual enhancement extremely subtle. “It’s so beautiful,” Griffin told me, beaming.

Although Griffin has the property portfolio of a Saudi prince, his vibe is more that of a suburban dad. He comes to some meetings in a polo shirt and jeans. He likes Coke at breakfast and Häagen-Dazs with hot fudge. He once said publicly that the “joke is you can tell how stressful it’s been by how much my waistline has grown over the last few months.” In 2016, a new Citadel employee in Chicago ran into Griffin in an elevator; he was carrying a takeout bag from McDonald’s. He loves video games, especially Call of Duty, where winning, he explained to me, “is all about making killstreaks happen.” He cycles and skis. He hasn’t bought a sports franchise yet, though in 2022 he and some partners nearly bid for Chelsea Football Club in the U.K., and a year later he thought about attempting to buy a minority stake in the Miami Dolphins.

His three kids, all teen-agers, attend a private school in Miami. Griffin has been unmarried since 2015, when he and Anne Dias, the mother of his children, divorced after eleven years of marriage. Dias reportedly requested a million dollars a month in child support, but she and Griffin settled before the case went to trial, after embarrassing headlines for them both.

Griffin does not discuss his dating life, but he was eager to talk to me about his art collecting. “I’ve always been interested in Jackson Pollock,” he said, then caught himself coming off as a born aesthete. “Actually, that’s not true. Let me be clear—I had no interest or knowledge about art whatsoever until I was almost thirty.” Now, he told me, he sees art as “one of the few ways that we as humanity separate ourselves from being animals.”

Griffin has made multiple art loans to the Norton Museum of Art, in West Palm Beach. One crowded room there has some of his early acquired pieces, including an edition of Degas’s “Little Dancer” sculpture that, he told me, was the “real start” of his interest in art. He first saw it not at a museum but while stopping by Sotheby’s in 1999.

Other parts of the Norton have more mature Griffin acquisitions, including a Rothko, a de Kooning, and a small Pollock. Given the publicly known price of some of Griffin’s acquisitions, which are a fraction of his collection, the total value of his art purchases is almost certainly in excess of two billion dollars. His collecting mirrors other impulses in his life: a yen for the “best”; practical investment logic (Impressionists, he told me, are “all but impossible to collect”); patriotic attachment to America at its most world-conquering. It also signals a desire to be more like an old-school plutocrat than like a tech billionaire who goes to Burning Man. The centerpiece of Griffin’s collection is “Interchange,” a de Kooning painting. It hangs at the Norton, and has never been in Griffin’s possession. He described it to me as “one of the most important paintings of the last hundred years.” He added, “It’d certainly be on a Top Ten list.”

Griffin told me that he’s too busy right now to build a museum to house his various collections, but he admitted that the thought has occurred to him. In addition to the art and the stegosaurus, he owns a copy of the Emancipation Proclamation; a draft of the Bill of Rights; a copy of the Thirteenth Amendment; and two of the fourteen surviving original copies of the Constitution. He paid forty-three million dollars for the first copy. He hasn’t disclosed the price of the spare.

His own museum may remain notional for now, but Griffin can visit at least thirteen art, science, and history museums and seven hospitals that carry his name on buildings, centers, or wings. After he donated a hundred and twenty-five million dollars to the Museum of Science and Industry in Chicago, in 2024, it became officially known as the Griffin Museum of Science and Industry. He has given away more than two billion dollars in total, almost all of it in the U.S., much of it to established institutions, including the University of Chicago’s economics department and Memorial Sloan Kettering, the New York hospital. He also wrote a check to secure a new head coach—an Argentine—for the U.S. men’s national soccer team.

Although Griffin has expressed concern that, at élite universities such as Harvard, “whiny snowflakes” have become “caught up in a rhetoric of oppressor and oppressee,” he has given generously to his alma mater. He has also made high-profile donations to Success Academy charter schools, criticizing the “human-capital tragedy” of New York City’s not allowing the schools to expand, a complaint that echoes ones he made in Chicago. An education focussed on “excellence,” he likes to say, is “the on-ramp to the American Dream.”

Miami, he believes, is a place where the American Dream still lives. He and his children moved there in 2022. He loves the city’s safety and openness to business, but told me that there is work to be done on education, roads, public transportation, and “chronically short” housing. During the pandemic, Miami was hyped first by crypto bros and then by New York financiers who envisaged creating a “Wall Street South.” They were drawn in part by the absence of state and local income taxes. (Griffin has recently been joined there by Jeff Bezos and by Sergey Brin, a founder of Google.) The two Citadel businesses now have about five hundred employees in Miami, most of whom moved with Griffin from Chicago.

Griffin was a champion of Chicago for most of his thirty-two years there. He was a friend of the former Democratic mayor Rahm Emanuel and was proud of what he saw as the city’s culture of coöperation between business and politics. But he had concerns about corruption, crime, underfunded pensions, and education, as was caustically evident in a speech that he gave to the Economic Club of Chicago in 2013. Decrying the city’s public schools, he declared that “the Democratic Party is captive to the unions and not captive to the children.”

“Well, we know I didn’t do it. I gave up stabbing years ago.”

Cartoon by Lars Kenseth

In the 2018 gubernatorial race in Illinois, J. B. Pritzker, a billionaire himself, defeated the incumbent, Bruce Rauner, a former private-equity manager whom Griffin had supported. Griffin told me, “When J.B. became governor, I sat down with him and said, ‘If you’ll do pension reform, I will publicly support you for a tax increase.’ ” I asked Griffin whether Pritzker thought about it. “No,” he said. “He more or less told me to pound sand.” (Pritzker’s office declined to comment.)

David Greising, the president of the Chicago-based Better Government Association, told me that Griffin and Pritzker engaged in a “blood feud” for years. (A spokesperson for Griffin said that his disagreements with Pritzker were “rooted in concerns about the state’s future, not personal animosity.”) Griffin won the first battle, in 2020, by spending more than fifty-four million dollars to defeat Pritzker’s plan to institute a progressive tax increase. But Griffin—who last year told his employees to be “hardball” players who seek to win not in a squeaker but in a rout—also sought to defeat Pritzker’s reëlection bid, in 2022. In the run-up to the election, Greising recalled, Griffin issued public warnings about Citadel potentially leaving Chicago while also conducting a “beauty contest” of Republican candidates who could challenge Pritzker. Griffin ultimately backed Richard Irvin, the Black mayor of a Chicago suburb, giving fifty million dollars to the campaign. But, Greising said, Griffin “made such a feeble choice that all the money in the world couldn’t buy him” a winner. Griffin announced Citadel’s move to Miami five days before Irvin—as predicted—was routed in the primary. The financier spent more than four hundred dollars on each vote that Irvin got. Pritzker won reëlection easily.

“No one was surprised” when Citadel left Chicago, Griffin told me. After all, he’d publicly called the city “like Afghanistan on a good day.” He and Beeson emphasized to me that crime was the main cause of their departure. Beeson told me that an employee had been stabbed near the office. Griffin talked publicly about bullet holes in the façade of the building where he lived. (Last year, Chicago recorded the fewest murders since 1965.)

Griffin’s attempts to influence politics have gone well beyond Chicago. Between 2020 and 2024, he spent four hundred million dollars on public campaign contributions in Florida and Illinois, and in federal elections. OpenSecrets lists him as one of the top five donors to federal races in the past three election cycles. (Griffin recently told me that he suspects his over-all political giving in 2026 will be less than in the past, noting, “The aperture of where we’re focussing our contributions is just narrower.”) Cason Carter, Griffin’s top adviser on philanthropy and politics, told me that Griffin isn’t a “political socialite” and rarely meets candidates—he’s more interested in their policy agendas. Griffin emphasized to me that a lot of his money went to Republican congressional candidates who were “different than historical voices,” such as “women of color” and “ex-military” types. But he also supports the Old Guard. In late May, he made his largest reported contribution of this election cycle, two and a half million dollars, to support Susan Collins, the Republican senator from Maine. Collins’s left-populist opponent, Graham Platner, has proposed a five- to six-per-cent annual federal wealth tax. Platner disparaged the gift to Collins in an online video, saying that Griffin’s goal was “helping her buy this election,” and that such gifts should “be illegal.” (Griffin dismissed the critique, telling me, “The Mamdani tweet was sent to me by countless friends and acquaintances. Platner’s tweet was sent to me by no one.”)

Griffin seems to consider his pulpit to be as important as his checkbook. He speaks on more topics, and in more venues, than any of his financial peers, almost always at such cozy forums as Davos. His commentary is measured, and he often comes across as a shadow Secretary of the Treasury. Sometimes he can be a bit more tart. Last year, when he was asked about Trump’s One Big Beautiful Bill Act at a publicly broadcast Citadel Securities conference, he answered, “I don’t think there’s a nice way to put lipstick on that pig.” After pausing for home-field laughs, he returned to form, calling the bill a “pro-cyclical tax cut late in the economic cycle.”

In Miami, Griffin told me, “I’d like to keep the Republican Party the party of small government, personal freedom.” In contrast to MAGA nihilists, he frequently talks about the value of government: “I think your best private philanthropy is philanthropy that encourages the public government to do things that are necessary for the common good that would otherwise not be on their radar.” During the pandemic, he called up Jared Kushner with the outline for what became Operation Warp Speed—the plan to create a COVID vaccine as quickly as possible. “Jared just ran with it,” Griffin told me.

Last year, Griffin said on CNBC, “Every single policy in Washington should have one focus and one focus only—how do we grow our economy?” This, he has noted, should not be at the expense of “equity and fairness,” adding that tax increases must be “on the table.” (According to ProPublica, between 2013 and 2018 he paid an average tax rate of 29.2 per cent—much higher than, say, the 13.7 per cent paid by Mark Zuckerberg.) More often, though, Griffin talks about American debt, competitiveness, and sagging productivity.

He presents his ideas as patriotic advice. For a man the former Trump adviser Steve Bannon once sneeringly called a globalist with “the political instincts of Louis XVI,” and whose firm has a hundred and fourteen nationalities on staff, Griffin is surprisingly consistent in saying that his goal is for America to win. Discussing visas with me, he lamented the possibility of “a gifted student in mathematics and physics that chooses to stay in China.” He said he’d rather immigrants “wear the Team U.S.A. jersey and build great businesses in America than compete by running great businesses in foreign countries.” When our conversation turned to the liberal politics of professors at élite universities, he told me, “All of those guys are anti-United States. This doesn’t mean I don’t have my criticisms. . . . But the starting position should be ‘This is the greatest country in the world.’ ”

Griffin supported Marco Rubio in the 2016 Republican Presidential primary and Nikki Haley in 2024. He’s never given a campaign contribution to Trump. (He donated a million dollars to Trump’s Inauguration in 2025, but he also gave half a million to Joe Biden’s.) He decided to vote for Trump in 2024, although, as he said before the election, it was “not with a smile on my face.”

Griffin’s most frequent complaint about the Biden Administration was what he calls its “endless onslaught of pointless litigation and pointless regulation.” (That being said, in the Biden years his estimated net worth doubled.) The new Administration hasn’t made him much happier. At last year’s Citadel Securities conference, Griffin said that the Trump Administration has done “a lot that we love and a lot that we hate.” He has condemned most of Trump’s major economic initiatives: tariffs, meddling with the Federal Reserve, nostalgic favoring of the manufacturing sector. Although Griffin supports tighter enforcement of immigration at the border with Mexico, he said in 2021 that Trump’s “willingness to attack people on the basis of where they came from or the color of their skin was completely inappropriate.”

That was a rare public personal criticism of Trump—and one he dared make only when it seemed that Trump was permanently out of power. Nowadays, instead of naming the President, he prefers to say, for example, that “the U.S. government’s” favoritism toward political allies and interference in the economy are “incredibly distasteful.” Griffin likely had mixed feelings when, last fall, the Wall Street Journal anointed him “Wall Street’s Loudest Trump Critic.” He has made a point of saying that Trump’s “choices come from a good place,” and that the President is “very different in a small room,” something that is “quite touching” to behold.

This carefulness is clearly strategic. In 2024, a CNBC interviewer at a conference exclaimed, to applause, “You need to run for President, Ken!” To many in finance, Griffin has taken the slot formerly held by the JPMorgan Chase C.E.O., Jamie Dimon: an outspoken king of Wall Street who could become a technocratic moderate in the White House. Griffin has encouraged these speculations. At a conference in February, he said, “I’d like to believe that at a future point in my life, I will be involved in public service.”

Griffin told me last week that he has no current plans to run for anything: “There’s not been a meaningful shift in my position over the last six to twelve months.” One reason might be that he is never interested in losing. None of his predecessors who tried to parlay Wall Street success into a shot at the American Presidency—from Hamilton to Harriman to Romney to Bloomberg—ever won.

Moreover, if Griffin stepped into public life now, the cynical wags in finance would declare the reason obvious—his hedge fund’s returns have been sagging. As a senior investment professional at a large institution told me, it’s axiomatic that a hedge fund’s performance is “inversely proportional to the amount of exposure the head guy or gal is getting on TV.” Although Citadel Securities has reported record revenue so far this year, the hedge fund delivered a return of just 10.3 per cent last year—worse than the industry average for only the second time since 2008. Through May of this year, it’s up only 3.9 per cent, according to Business Insider. Griffin portrayed this to me as the consequence of intentional caution, given that so many potential Wall Street bets are “being driven by a singular question, which is: how long will the Strait of Hormuz be closed for?” Perhaps, but H.F.R. has reported that the industry average is up 7.1 per cent over the same period.

Griffin admitted to me that running the hedge fund could be wearying: “There are parts of it I love and parts of it I hate.” He certainly seems to enjoy mixing it up with Mamdani, and buying a Constitution or two. But, ever since high school, the first order of business for Griffin has been business. He expressed confidence to me about his ability to get Citadel traders to stop “waiting for softballs.” Many current employees, no doubt, will not last long. His task is “getting people to really get back in—I hate to say it—the grind-it-out reality that defines most of the life of an investment firm. . . . You have to see the details the competition hasn’t seen.” He promised, “This won’t take us long to do.” ♦