So Griffin has been on my list from day one. Like, he’s the 32nd richest person in the world with a net worth of $60 billion, but I was in no real rush to cover him until about two weeks ago, when I finally got round to watching Dumb Money — the movie about the GameStop short squeeze — and it’s a pretty good movie.
But in the film, the two or three times when Griffin's name is mentioned, it’s followed by the word “prick”.
So that got me really interested.
Is he that bad, or is it simply jealousy as a result of his success?
Because even compared to the other Masters of the Universe on Wall Street, Griffin is seriously successful. His hedge fund is the most successful hedge fund ever in history, but even more than that, he has a second separate business, a securities business, and it trades more than $170 trillion worth of securities a year, making it one of the biggest trading businesses in the world.
How did he get to where he is?
This is a fascinating story.
Harvard, Computers and Convertible Arbitrage
Ken Griffin was born in Daytona Beach, Florida, in 1968. His father worked at General Electric, his mother was a housewife.
By the time Griffin is a teenager, he’s big into computers, taking them apart, learning to program.
After finishing high school he went to Harvard to study economics and government, and he said that it was around this time that his main ambition was to get into private equity.
I’m guessing he was heavily influenced by probably my favourite book, Barbarians at the Gate, which was released around this time, because Griffin said that his hero back then was Henry Kravis of KKR, who is one of the central characters in that book.
Myself and Keith did an episode on Barbarians at the Gate about two years ago, so that’s well worth a listen.
While he's at Harvard, Griffin starts trading and spends a huge amount of time learning how the markets actually work.
And he comes across something called convertible arbitrage.
The basic idea is that a company might issue a bond that can eventually be converted into shares of its stock. Because of that option, the price of the bond and the price of the stock are tied together.
But back then, markets weren't as fast, and sometimes the bond price lagged behind the stock price.
If the stock price jumped, the bond was supposed to go up too, but sometimes it was slow to catch up.
So Griffin would buy the underpriced bond and simultaneously bet against — or short — the stock.
Shorting the stock protected him if the market crashed, making the trade virtually risk-free.
As soon as the bond price caught up to where it was supposed to be, he closed the trade and pocketed the difference.
He then writes a computer program to find these opportunities AND calculate how to hedge and manage the trades.
And now he needs money.
So he visits a broker friend working in a bank and starts explaining his model, and by pure chance a wealthy retired Wall Street investor overheard Griffin’s pitch and said he’d invest $50,000.
And then, on the back of this and obviously feeling pretty confident, Griffin goes to family and other contacts and raises $265,000.
And to ensure that he can get live market prices quickly, Griffin persuades Harvard to let him put a satellite dish on the roof of his dorm.
By the time he graduated from Harvard in 1989, he's managing more than $1 million.
He closed that fund and got a job at Glenwood Capital, a hedge fund in Chicago.
In his first year he produced a return of around 70%.
Frank Meyer, one of the founders of Glenwood, said the following of Griffin: “Ken is the most focused human being I've ever met. He calculates probability distributions while other people are clearing their throats”.
Building Citadel
Meyer is so impressed that in 1992 he helped Griffin to raise $4.6 million and start his own hedge fund.
Now initially it wasn’t called Citadel, that happened a few years later, but I’m going to stick with Citadel.
Meyer also gives Griffin one really important piece of advice.
Instead of charging investors the usual fixed management fee of 1 or 2%, he tells Griffin to charge them the actual cost of running the fund.
And this fee can fluctuate — at times it’s been as high as 6%.
So Citadel can spend much more heavily on things like computers, programmers, data and faster systems, because those costs are passed on to investors.
And as we’ll see, that continued high investment in technology is crucial to Citadel's success.
Now, as you’d expect for someone as intensely focused as Griffin, he pretty much lives and breathes the business, arriving before six every morning and working 18-hour days, generating 40% returns, so money starts flooding in.
By 1994 the hedge fund is managing $200 million with over 60 employees.
Griffin is very involved in the hiring process.
Over the years Griffin estimates that he has interviewed 10,000 people, and this is because he’s very particular about the type of people he wants.
In these early years he favours young, hungry, raw talent, and he’s not just looking for traders, he’s looking for problem solvers — theoretical physicists, mathematicians, programmers and engineers — people who can look at markets as a problem to be solved rather than just something to have an opinion on.
Because this is the thing about Griffin — he’s not an innovator, he’s a problem solver and an unbelievably focused replicator, as is highlighted in an excellent profile piece from the New Yorker magazine where they wrote the following:
“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.”
So if any of his competitors are doing something new or different that’s making money, Griffin wants to understand it, build the systems around it and then do it better.
And you see, Griffin immerses himself in this process. He’s all over the technology that they use, he understands it inside out, and this is a quote from him:
“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.”
The LTCM Opportunity
By 1998 Citadel was managing about $1 billion and earlier that year Griffin tightened Citadel's rules around withdrawals, so his investors couldn't suddenly demand all of their money back.
And this turned out to be very prescient because later that year LTCM blows up.
So LTCM was one of the biggest hedge funds in the world, and its founders included two Nobel Prize-winning economists.
But they had borrowed far too much money.
So when Russia defaulted on its debt, LTCM collapsed and this had a huge knock-on effect.
Other hedge funds and banks start dumping things like corporate bonds, convertible bonds and other credit investments because lenders are demanding more cash from them and investors are trying to get their money out.
And because everybody is selling at the same time, some of these assets are suddenly available at knock-down prices.
But because Griffin had tightened Citadel’s rules around withdrawals earlier that year, he’s not under pressure.
He can buy.
And that’s exactly what he does.
He starts buying these distressed bonds and other credit investments and then waits for the panic to pass and prices to recover.
And this becomes a bit of a Griffin playbook.
Wait for somebody else to get into serious trouble, then step in as the buyer of last resort and pick up valuable assets for a fraction of what they were worth before the panic.
Citadel Securities
Up to now, Citadel is your basic, albeit very high-performing and opportunistic hedge fund.
But Griffin decides he wants to get much closer to the actual buying and selling of shares.
And so in 2002 he launched Citadel Securities.
It’s what’s called a market-maker.
And in very simple terms, a market maker buys from people who want to sell and sells to people who want to buy.
So it might offer to buy a share for $10 and sell it for $10.01 or $10.05.
That tiny difference is the profit.
And if you're doing that millions of times a day, it becomes a very big business.
Griffin spends tens of millions on servers, communications lines and trading software to build up this side of the business.
And by the end of 2004, Citadel Securities is handling roughly 12% of all US options volume and about 3% of listed US equity trading.
And you see, the reason this business takes off so quickly and then keeps growing is all down to the way in which Griffin focuses on what’s working in the market, replicates it, measures it, changes it, and keeps improving it until Citadel becomes the best.
As the COO of Citadel said: “We don’t enter a business just to make a little money. We enter a business to be number one. Every single time.”
And their models are the best.
One rival executive said the following: “The truth is, they have some of the best pricing in the business; how they do it I don’t know.”
Another rival says: “We trade with them a lot and begrudgingly respect them.”
2008: Citadel Comes Close to the Edge
So by 2007, between the hedge fund and Citadel Securities, everything is going brilliantly for Griffin.
And then the subprime mortgage crisis starts.
Griffin basically goes back to the LTCM playbook.
Other people are in trouble, they need cash, Citadel has cash, so Griffin swoops in.
He buys distressed credit assets from a collapsing hedge fund at a steep discount.
A few months later ETrade gets into serious trouble because of its exposure to subprime mortgages.
Citadel put in around $2.5 billion, picking up mortgage assets for around 27 cents on the dollar.
It looked like good business.
But then on September 15th 2008, Lehman Brothers collapsed.
Credit markets freeze.
Banks start demanding more collateral.
Assets that Citadel thought it could easily sell become almost impossible to move.
Now Citadel is highly leveraged, which basically means it has borrowed a lot of money to make its trades much bigger.
So while Citadel does have plenty of cash, compared with the size of those trades, that pile of cash doesn't actually go very far.
Because as the value of those trades falls, the banks lending Citadel money start demanding more and more cash as collateral.
If you need more cash, you have to start selling assets.
But Lehman has just collapsed, the financial system is in free fall and everybody else is trying to sell as well.
So Citadel is having to sell some investments at huge discounts, resulting in big losses.
Wall Street is full of rumours that Citadel can't meet margin calls and is about to go under.
CNBC actually parks a truck outside Citadel’s Chicago headquarters waiting for the collapse.
Griffin tries to assure investors, telling them:
“We’ve made it through 18 years. We will make it through the next six to eight weeks.”
But some investors want to withdraw money from the fund and Griffin knows that if this happens he’ll be forced to sell even more assets at even bigger losses.
So he activates a clause in the fund rules that allows Citadel to temporarily stop withdrawals.
Investors are furious, understandably, because their money is now locked in.
But this decision, together with Griffin and some top Citadel executives putting in $500 million of their own money, buys them some time and ultimately helps to keep the fund alive, although around $8 billion of value is wiped out from its main funds.
But that’s the hedge fund side of the business.
Citadel Securities, the market-making business, actually had its best year up to that point, making more than $1 billion in 2008.
And the reason is pretty simple.
Markets were going crazy, and because of all of the uncertainty, the gap between the buying price and the selling price got wider.
So Citadel Securities was making more on each trade.
And that’s the interesting thing about this business.
When markets are calm, it makes tiny amounts on huge numbers of trades.
But when markets become really volatile, volumes are still high and the gaps between the buy price and sell price can get wider.
What a great business to be in.
It took until 2012 for Citadel's hedge fund business to fully recover.
“A Gift to Be There and a Gift to Leave”
Now, given Griffin’s own workaholic nature, combined with his intense focus on ensuring Citadel stays on top of everything — the data, the trends, the models, the technology — it comes as no surprise to hear that Citadel developed a reputation as one of the toughest places on Wall Street to work, with a huge turnover of staff.
Here’s a quote from one former employee: “(its) "real sweatshop... You have to be willing to give your life up to work there."
In short, if you’re not performing, there isn’t a huge amount of patience.
You’re gone.
But that shouldn’t come as any surprise.
Wall Street is massively competitive and Citadel is in the Premier League as such.
We saw the exact same thing when I did the episode on Steve Cohen's hedge fund — only the best employees are kept.
Look, it’s undoubtedly a real pressure cooker of an environment to work in, but it’s also one hell of a learning curve and I love this line from one former employee:
“It was a gift to be there and a gift to leave.”
Griffin does seem to go to extremes when it comes to employee NDAs and non-compete agreements.
For example, he’s lobbied for laws that allow companies to enforce non-competes lasting up to four years.
Now, there is a bit of irony in this.
Because while Griffin does everything he can to stop his own people leaving for competitors, he has also built a reputation for poaching the best people from his competitors and it drives them nuts.
And you get a great example of this in 2005.
Citadel poached a trader from Greenlight Capital, the hedge fund run by David Einhorn.
And Dan Loeb, who runs Third Point, another hedge fund and is a friend of Einhorn’s, sends Griffin an email that includes the following:
“I find the disconnect between your self-proclaimed 'good to great, Jim Collins-esque' organization and the reality of the gulag you created quite laughable. You are surrounded by sycophants but even you must know that the people who work for you despise and resent you.”
Now Griffin didn’t respond publicly to this.
And these kinds of emails were very much Loeb’s thing back in the 2000s.
He was well known on Wall Street for sending extremely aggressive emails and then copying Wall Street heavyweights and financial journalists on the email.
And that’s the bit I don’t like.
It’s all very performative, Loeb trying to show everyone he’s the alpha, but of course it only makes him look petty and insecure.
Anyway, if you do manage to stay working with Citadel, if you perform, the money is very good.
A junior employee in their first year can earn anything from $300,000 up to $600,000, while top-performing portfolio managers in a really good year have earned bonuses of $50–$100 million.
And Griffin also spends huge amounts on staff events.
Probably the best example was in 2022, when Citadel celebrated its 30th anniversary.
Griffin flew his 4,000 employees and their families, bringing the total to 10,000 people, to Orlando, paid for the flights, the hotels, the food and the tickets, and basically took over parts of Disney World and Universal Studios.
Divorce, Covid and the Four Seasons
Now getting back to where we left off, it was 2012, the hedge fund had rebounded from the financial crisis, Citadel Securities was thriving and throughout the 2010s both businesses continued to grow.
And probably the biggest distraction for Griffin personally is his very public divorce from his second wife, Anne Dias, the mother of his three children.
It became one of the most high-profile and sensationalised legal battles in 2014/2015.
The couple had signed a prenup when they married in 2003, but Dias argued that she had been pressured into signing it on the night before their wedding and hadn't been given enough time to properly consider it.
Griffin's lawyers disputed that and they produced evidence showing the prenup wasn’t sprung on his wife the night before the wedding but that in fact it had been actively negotiated for weeks before the wedding, with multiple drafts exchanged and reviewed by his wife's lawyers.
Jesus, how romantic.
It became a very public and pretty messy dispute before Griffin and Dias eventually settled in 2015, just as the case was about to go to trial.
So jump forward a few years to 2020.
Covid hits.
Everyone is stuck at home with nothing to do, retail trading — or trading by ordinary people — goes crazy and Citadel Securities has its biggest year, almost doubling revenue to $6.7 billion.
And Griffin is determined to keep the operation running.
So as soon as the lockdowns begin, he leases the entire Four Seasons hotel in Palm Beach, Florida.
Over five days, technicians dig fibre-optic lines through the sand and turn the hotel's conference rooms into proper trading floors.
Around 50 Citadel traders, engineers and their families move into the hotel.
And once they're in, the place is effectively sealed.
GameStop
Now because trading goes through the roof during Covid, we see the emerging popularity of apps like Robinhood, and this brings us to the story that puts Griffin in the crosshairs of a lot of Robinhood users.
I am, of course, talking about the GameStop short squeeze.
In January 2021, thousands of ordinary investors pile into shares of GameStop, the video-game retailer that a number of hedge funds have been shorting or betting against.
One of the funds in serious trouble is Melvin Capital, run by Gabe Plotkin.
As we now know, Griffin loves to prey on distressed funds, so Citadel agrees to invest $2 billion into Melvin.
Now Citadel has done this kind of thing before.
But there is one complication.
Griffin’s other business, Citadel Securities, is also the biggest firm handling Robinhood’s customer trades.
And three days after Griffin’s $2 billion investment in Melvin, Robinhood suddenly restricts customers from buying GameStop and several other shares.
So people conclude that Griffin must have told Robinhood to do it to safeguard the $2 billion investment in Melvin.
The problem is that neither the logic nor the evidence support the conspiracy theory.
For example, on January 27, the day before Robinhood’s restrictions, Citadel Securities handled nearly $4.2 billion worth of GameStop trades, so it was making an enormous amount of money from all of this trading.
So if Citadel had pushed Robinhood to stop the buying, it would have been deliberately damaging one of its own most profitable businesses at exactly the moment trading volumes were going through the roof.
And the other important point is that Citadel the hedge fund wasn’t in any real danger of losing its $2 billion investment.
Melvin still had billions of dollars of other assets, and even though Melvin ultimately did collapse, Citadel got its $2 billion investment back out of Melvin in stages.
Then there were official investigations.
The SEC looked into what happened. Congress subpoenaed emails and internal communications.
And investors also brought a civil case alleging that Citadel and Robinhood had conspired to shut down the trading.
But none of them found evidence to support that theory.
A civil case was dismissed, and that dismissal was upheld on appeal because there was no evidence.
The truth, of course, is far more boring.
Trading in GameStop had gone crazy, and because trades still took two days to fully settle, Robinhood had to put up cash to its clearing house to cover the risk in between.
And the more frantic the trading became, the more cash Robinhood had to put up.
By the morning of January 28th, that figure had risen to around $3 billion.
Robinhood simply didn’t have it.
So it stopped customers buying some of the most heavily traded shares, which of course included GameStop.
And by doing that, it reduced the amount of cash it had to put up.
The Most Profitable Hedge Fund of All Time
Anyway, the GameStop controversy didn’t make a dent on Citadel.
As of 2025 the hedge fund has $72 billion under management, and since it was founded, it has generated more than $90 billion in net profits for investors, making it the most profitable hedge fund of all time.
Citadel Securities, meanwhile, has become one of the most important trading firms in the world, trading more than $170 trillion worth of securities in 2025 alone.
And it now handles around a quarter of all share trading in the United States and is the number-one market maker in the country.
And to put that into perspective, Citadel Securities handles more daily stock volume than entire national exchanges, including the London Stock Exchange and the Tokyo Stock Exchange.
So that’s why Griffin is now the 32nd wealthiest person in the world with a $60 billion fortune.
And like nearly every hedge fund billionaire, Griffin spends his money on property and art, but even by the standards of the super wealthy, Griffin’s spending is pretty eye-watering.
His art collection is worth around $2 billion — he spent $500 million on just two paintings.
In 2019, Griffin bought a four-floor penthouse overlooking Central Park for $238 million — at the time, the most expensive home ever sold in the United States.
And over the last ten years, Griffin has spent more than $450 million buying up neighbouring oceanfront properties in Palm Beach, Florida, giving him around 27 acres with nearly a quarter-mile of continuous oceanfront.
And on that land, he plans to build a 50,000-square-foot mansion with separate guesthouses.
By the time it’s finished, the total cost could be around $1 billion, making it one of the most expensive private homes ever built.
And look, he can do what he likes with his money, but personally, I find that kind of spending, that kind of opulence a bit distasteful.
Politics and Public Office
Now unlike a lot of other prominent billionaires in the US, while Griffin is a Republican, he’s not exactly a Trump fan and he’s pretty vocal about it.
He voted for Trump in 2024, but he said it was “not with a smile on my face.”
He’s said that the Trump Administration has done “a lot that we love and a lot that we hate.”
He’s condemned most of Trump’s major economic initiatives: tariffs, meddling with the Federal Reserve, and although Griffin supports tighter controls on immigration at the border with Mexico, he said the following:
“[Trump’s] willingness to attack people on the basis of where they came from or the color of their skin was completely inappropriate.”
Now the reason why Griffin has been so vocal in criticising a lot of Trump's initiatives is that he seems to be setting out his stall to run for public office, maybe even the presidency.
And here’s a quote from him:
“I would never say no to the possibility of being involved in our government. I don’t think 2028 is that moment in my life.”
But he's still only 57 years old.
Come the 2032 election he’ll be 63.
So, Is Ken Griffin Really That Bad?
And I’ll finish up by circling back to the reason I wanted to dig into Griffin in the first place: the perception given by some of his competitors on Wall Street that he’s not a nice guy.
And having gone through the research, I was expecting to find something that would make me think, yeah, this guy is such a prick.
I didn’t.
Yeah, he’s a tough taskmaster, he’s totally focused on winning, but there’s no real skeletons that I could find, no stories that made me go, oh, he’s a nasty piece of work.
Maybe I just didn’t find them.
But I think a lot of the animosity from his competitors comes down to the fact that Griffin is just an incredibly difficult person to compete against.
He doesn’t play by their rules and he beats them.
When another hedge fund gets into trouble, he doesn’t come along offering sympathy — he buys their assets for a fraction of what they were worth.
He’s incredibly aggressive when it comes to poaching the best traders at rival firms while also enforcing stringent non-compete agreements to stop his own employees from going to competitors.
Also, because Citadel has such a high turnover of staff, there are now an awful lot of former employees scattered around Wall Street who don’t have good things to say about him.
And then combine all of the above with his huge success, because not only has Griffin built the most profitable hedge fund in history, but on top of that he built Citadel Securities, one of the biggest trading firms in the world.
So yeah, I think among the huge egos on Wall Street there is a lot of jealousy and resentment towards Griffin.
But whatever you think about Griffin, I think he makes for a fascinating story.