The quietest billionaire you’ve never heard talk. Builder of a probability machine, not a brand.
Born in 1958 in New York to a middle-class family, Jeff Yass studied mathematics and economics at Binghamton University and later earned an MBA from NYU.
No silver spoon. Just a deep obsession with numbers and odds.
Before Wall Street, Yass was obsessed with poker, blackjack, and horse racing. Not casually. Professionally.
He studied expected value, risk sizing, and probability distributions. One idea stuck early:
You don’t need to be right often. You need to be right when it matters.
In the 1980s, Yass traded options on the Philadelphia Stock Exchange. Options trading is not investing—it’s structured betting.
Most people lose. Yass didn’t, because he treated markets like math problems, not stories.
At around age 29, Yass co-founded Susquehanna International Group (SIG).
No press. No grand vision decks. Just discipline, risk limits, and data—before data was fashionable.
SIG hired poker players, chess players, and math nerds. Culture mattered more than credentials.
Most traders ask, “Is this a good stock?” SIG asks, “What’s the probability this price is wrong by a tiny amount right now?”
They use statistics, probability, game theory, and historical patterns. They don’t predict the future. They price risk better than others.
Humans trade a few times a day. SIG’s computers trade every millisecond.
Each trade earns almost nothing. Millions of trades turn crumbs into feasts.
Being right 51% instead of 50% sounds trivial. Over millions of trades, it’s enormous.
One coin flip means nothing. A billion slightly biased flips creates a fortune.
No marketing. No support calls. No branding. Just engineers, traders, and servers.
Costs stay low. Focus stays absolute.