He Turned Down Ken Griffin to Run His Own Fund. That Was $20 Billion Ago.
Hamza Lemssouguer, 35, is shaking up the London finance scene with his big short bets
In 2020, Hamza Lemssouguer received an offer to manage several billion dollars for hedge-fund titan Ken Griffin, the founder of Citadel. He turned it down.
Now Lemssouguer manages $20 billion at his own hedge-fund firm. The 35-year-old launched Arini Capital with $1.3 billion and a reputation for bold bets in 2022 and has been the fastest-growing new hedge-fund manager since then, according to data-provider Hedge Fund Research.
He’s also drawn fire from competitors eager to see an end to his run of winning short trades, bets that prices of corporate bonds and loans would fall. Lemssouguer made prescient trades ahead of the Covid-19 pandemic and the software industry selloff this year.
Moroccan-born Lemssouguer sticks out in London’s clubby finance scene. He neither drinks alcohol nor drives a car and his hobby of choice is raising parrots. He has a casual demeanor and speaks English with an American accent picked up bingeing shows including “Entourage” and “The Fresh Prince of Bel-Air.”
“Being young and also being an outsider and unconventional allows [me] to not be arrogant towards the market,” Lemssouguer said in an interview at the 400-year-old Tudor estate outside of London where he and his wife live with their child and 160 rare parrots.
Arini is run by a tightknit team of analysts and traders from countries including Afghanistan, Turkey and Ukraine. The firm focuses on heavily indebted companies, offering loans to some while buying and shorting bonds of others—often supersizing its trades.
Competing fund managers and bank traders say Lemssouguer’s approach is overly aggressive, causing his performance to swing wildly.
“He has a lot of haters,” said Rupak Ghose, who advised hedge funds as an investment banker and is now a finance-industry commentator. The critics argue Lemssouguer relies heavily on borrowed money, or leverage, to boost profits, a strategy prone to backfiring.
“Look at the track record,” Lemssouguer said. “We’re able to outperform in up markets and down markets with our strong risk management.” The fund has returned an average of 15% annually, according to people familiar with the fund, compared to the 7% average return of HFR’s index of credit hedge funds.
But Arini’s main fund has also lost as much as 6% in a single month and delivered a ho-hum 9% return last year, according to the same people, in part because Lemssouguer put on short trades while most markets went up.
A series of short bets made in the third quarter of 2025 on software companies including headhunter marketplace ZipRecruiter and IT-services provider Unisys initially failed to deliver. They kicked in early this year when fear of a “SaaSpocalypse” swept debt markets.
Arini executives said the firm outperforms because it uses a complex hedging tool meant to protect it from big losses. The model hasn’t been tested in a prolonged market downturn.
Arini closed its main hedge fund to new investors when it hit $4 billion because getting bigger would hurt performance, Lemssouguer said. The firm is growing other businesses like collateralized loan obligations and private credit, which pay lower fees than hedge funds but can grow much bigger. About 60% of the money the firm raised comes from North America.
Unlike the pod-shop strategy of firms like Citadel, where many different teams compete against each other, Arini’s funds all communicate and draw on views from the same 20 industry analysts. The strategy is something Lemssouguer hopes will help Arini pounce faster on investments. One potential drawback: Investments in different funds may become correlated as a result.
The contrarian
Lemssouguer grew up with three siblings in a modest apartment in Casablanca. His mother was a teacher and his father worked in the port. He was known as a quiet kid who excelled at three things: drawing, raising parrots and math.
The latter earned him a spot at École Polytechnique, a French mashup of M.I.T. and West Point, and his first job in Credit Suisse’s London office in 2014.
He became one of the bank’s top bond traders and was managing about $100 million of its money by 2016, when he became convinced that Jaguar Land Rover was headed for a fall.
“Revenues were going up and everyone thought they were on the verge of a credit ratings upgrade,” he said. “I took the contrarian view.” He had canvassed Jaguar Land Rover dealerships, and learned inventory was growing, indicating the automaker’s sales would soon slow.
He put about 10% of his portfolio in credit-default swaps that would gain value if bond investors turned bearish on the automaker. When sales dropped in 2017, the bank made about five times its money.
Jaguar set the pattern for Lemssouguer: Analyze the data, find conviction and make the trade as big as possible. He celebrated wins by playing music by his favorite rapper, the Notorious B.I.G., on the trading desk. Word of the big paydays spread inside and outside the bank.
“When I heard about Hamza’s first year, I thought ‘Whatever, anyone can get lucky,’ ” said a former colleague at Credit Suisse. “Then he did it a second year and I thought ‘He’ll lose it all next year,’ but he never did.”
When Covid spread in early 2020, he made short bets worth about $1 billion on companies he knew were tight on cash, like auto rental firm Europcar Mobility Group. The strategy made a $220 million profit in the first quarter of 2020.
Citadel offered Lemssouguer a job that year running a European credit portfolio. He accepted it, then backtracked when Credit Suisse countered by proposing to launch a fund for him with his old trading team. Plans changed again before the scheduled launch in early 2021, when Credit Suisse’s hedge-fund business imploded; so he found another backer, a large hedge fund named Squarepoint Capital.
Lemssouguer and his wife, a former trader, bought the country estate in late 2020. The pandemic had set in and his then-10 parrots were fast outgrowing their London house.
These days, pastel and fluorescent birds groom, preen and bicker in enclosures behind the home. Lemssouguer says he is trying to breed flocks of them so they can be reintroduced to the wild. He gives visitors tours in go-karts and occasionally plays pickup soccer on the lawn. A red tagine pot sits in their kitchen as a reminder of home.
Arini’s launch in early 2022 began badly. Russia invaded Ukraine and global interest rates jumped that spring, sending European corporate bond prices tumbling in unison. The fund lost 15% from March to September.
Lemssouguer regretted starting without a dedicated trader to insulate the fund’s investments against such shocks. Though Arini finished 4% ahead that difficult year, he recruited Deutsche Bank trader Ardacan Celebi, another graduate of a French math school.
Celebi built what the firm calls a “risk-mitigation engine,” which uses derivatives, bonds, exchange-traded funds and other instruments to absorb shocks, allowing Arini to make aggressive trades even when markets turn choppy, Lemssouguer said.
The model focuses on limiting the maximum potential loss, or “drawdown” of the portfolio, Celebi said. “That’s what can get you out of business.”