(BFM Stock Exchange) – With a heritage of sixty billion dollars, Jeffrey Yass co -founded the Susquehanna International Group investment company. He especially built his career and his wealth with mathematical formulas and probabilities, inspired by games of money, and largely supported the Republican Party. To the point of having been expected for a position in Washington.

If Warren Buffett remains largely the richest financier in the world, another laying of Wall Street is very high in the rankings: Jeffrey “Jeff” Yass. A 76 -year -old businessman co -founded the Susquehanna International Group investment company (GIS) and displays a heritage of 61 billion and 59 billion dollars respectively in Bloomberg and Forbes rankings. Jeff Yass is 23rd in the first ranking and the 25th of the second.

Since the start of the year, he has been one of the rare American billionaires to have “earn” money in the stock market storm. More than $ 15 billion more to its heritage. Only buffett did better in 2025.

This appearance septuagenarian could not be more ordinary attracted much more than usual light on his person. Bloomberg devoted an article to him in March, stressing that his fortune (then valued at 63 billion dollars) had doubled since the end of 2022, thanks above all to the participation of Susquehanna in Bytedance, the Chinese parent company of Tiktok.

Bytedance is not listed on the stock market. But the company recently offered its US employees to buy them titles at a price that exteriorizes a valuation of $ 350 billion, according to Reuters. Bloomberg, for its part, reported that several Bytedance investors had reassessed the valuation of the Chinese group between more than $ 400 billion and $ 450 billion.

According to an article in the New York Times, GIS has 15% of the capital of the Chinese mastodon while according to Bloomberg, Jeff Yass would hold 7% individually.

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Great donor of the Republicans

But it is above all his political connections that earned him to make some of the press, especially last year.

As Bloomberg reports, Jeff Yass invited Donald Trump to participate in a conference in March 2024, after the billionaire won the Republican primary, resigning himself to support him. Which turned out to be crucial at a time when Elon Musk had not yet joined the current tenant of the White House.

Above all, Yass has largely put their hand in the pocket to finance the Republicans, in particular the rivals of Trump in primary. According to Opensecrets data, the site of an American non -lucrative organization, Jeffrey Yass and his relatives paid a hundred million dollars between February 2023 and October 2024 to the Republican Party, via political action committees (“CAP”).

To the point that Bloomberg had mentioned in March 2024 his name among the potential contenders for the post of secretary to the Treasury, an American equivalent of the Ministry of Finance. This function was finally assigned to Scott Bessent.

GIS, the investment company co -founded by Jeff Yass therefore, even had shares in Digital World Acquisition. This investment vehicle (a spac, an empty shell) merged in March 2024 with Trump Media Technology Group, the company of Trump, which notably oversees its social social network Truth, allowing the company of the American president to break into the stock market.

Jeff Yass’s conversion to Trumpism was a flip-flop. The richest man in Pennsylvania, as American newspapers sometimes present, had told Wall Street Journal in 2022 that he was trying to discourage a candidacy of Trump. Quartz explains that he was even a “Never Trumper” in 2016.

Many media suggest that his support was certainly not disinterested, if only because of his marbles in Bytedance and therefore in Tiktok, the subject of a ban since 2024 in the United States. Donald Trump has suspended this ban, for the time being, until next June. A split or sale of the American activities of Tiktok by Bytedance could take place by then.

Le Pennsylvania Independent underlines that Jeff Yass also dropped “tens of millions of dollars to have influence on the Pennsylvania elections since 2010”. The financier notably spent $ 54 million to support Republican candidates in the mid-term elections of 2022.

Pro poker player at the end of the 1970s

Jeff Yass is a claimed libertarian. This current of thought fiercely defends private property and individual freedoms even if it means reducing the state to its most summary expression. And above all to limit interventionism. According to the Financial Times, the financier even judges that the fact that the American federal reserve controls the supply of money constitutes “a violation of our basic freedoms”.

Beyond his political views, Jeff Yass has mainly built a career marked by two very linked passions: game and mathematics. Son of two accountants, the businessman grew up in Queens, a district of New York. He studied at New York State University in Binghamton where he obtained a undergraduate diploma in mathematics and economics. According to Bloomberg, he would have described himself as having at the time, in the 1970s, a “typically socialist” spirit (this has changed well since).

According to Forbes, Jeff Yass then begins to take an interest in options, derivative products which gives the right and not the obligation to buy or sell a financial title at a price and over a given period.

His appetite for the economy applied to the game is, moreover, already palpable. He writes, as part of one of his courses, a thesis entitled “an econometric analysis of horse races”, which will be published in the magazine “Gambling Times”. He also plays with his friends in poker and they are carrying out hippic bets together.

Jeff Yass then spins with a friend in Las Vegas, in 1979. “I was freshly graduated, with a specialty in mathematics, and I was unemployable. So I went to Las Vegas playing poker for a year and a half,” he said in a video posted on GIS’s Youtube account.

Milton Friedman’s blessing

Two years later, an investor named Israel Englander offers him a seat on the Philadelphia Stock Exchange in exchange for 30,000 dollars and a sharing of his income at 50/50. After about a year, he took independence and then called his university friends with whom he played poker to help him in his trading business. He makes them understand that his activity turns out to be “very lucrative” to resume his own words.

Jeff Yass then specialized in the financial market options, using the advanced mathematical models of the famous Fisher Black economists, Myron Scholes and Robert Merton, the last two obtaining the Nobel of the discipline in 1997.

“Yass then relied on his well -established skills in terms of poker – how to read the subtleties of the markets, adjust according to new information and size betting – to keep his competitive advantage”, writes Forbes.

The financier then founded with its partners Susquehanna International Group in 1987, named after a river flowing in the United States and passes through its former university. The company undergoes criticism at its beginnings, in particular because it benefits strongly from the “Krach” of Wall Street from 1987 via sales options (“Put”). This pushes Yass to ensure with his idol, the illustrious liberal economist Milton Friedman, that he is doing nothing wrong, still reports Forbes. The famous academic will respond in the negative, judging that the activity of his company contributes to the efficiency of the markets.

GIS is employs more than 3,000 people today and explains having an approach based on technology and quantitative finance, a discipline based on the use of mathematics and probabilities.

Above all, this company is a mastodon of the trading of options. According to the Financial Times, the gross exposure of GIS can reach $ 500 billion in a given day, even if in reality many of these positions compensate by the game of the sum between those for sale and those purchasing. The “FT” gives another example, indicating that the company had options and actions representing an exhibition of $ 50 billion on Nvidia, the specialist in graphic processors, at the end of the second quarter of 2024.

“We are not Coca-Cola”

Jeff Yass continued to play and bet, especially on horse racing. Quartz reports that, towards the late 1980s, the trader had won $ 760,000 during a Paris session. Which then constituted a record.

Yass had properly predicted the order of seven horses in three races. Unsurprisingly, his forecast was not based on luck, but on an algorithm built with a statistician who would have worked with NASA.

This culture of the game is always found in Susquehanna. The group explains in particular using the game theory, a mathematical science which studies the rational decisions of companies and individuals, then called “agent”.

The company underlines that its employees play, to perfect their science of probabilities, to many games, such as poker (obviously) but also failures, backgammon, the set of set “the colonists of Catania” or the card game “Magic the Gathering” (one of the employees based in Sydney would even be a professional player).

A GIS division also operates on sports betting in many disciplines (hockey, football, American football, basketball, golf, etc.). The company explains applying in this area the quantitative finance models that have made its success in the financial markets.

GIS also cultivates a certain culture of secrecy, not publishing global accounts, and speaking little to the media, according to the FT. It would allow her young recruits to adopt a relaxed dress style and present a low turnover, especially due to non-competition clauses.

GIS also recruits very young, at the end of the school, its employees, before giving them intense training to infuse the spirit of Yass based on mathematics and games.

“We are not Coca-Cola, we have no products, we have nothing. The only thing we have is our faculty to hire malignant kids who leave the university and that are motivated, then to teach them how to trader,” explains Jeff Yass in the promotional video of GIS on Youtube.

“We have this culture which makes everyone speak the same language, which is in fact the language of probabilities and mathematical hope. We have here the culture which makes that if you have the best argument, you win, even if you are the youngest guy or girl in the office. If you are right, you are right, we laughed at the rest.” He insists.

According to Forbes, SIG uses poker tournaments to train and recruit its young wolves and young wolves. Three major global awards were won by his traders, and two of them wrote a book on mathematics applied to poker. We imagine that this is not to displease their chief and mentor.