How hard is it to get into Jane Street, which makes $40 billion a year?

Author: Rhythm

This week, the most discussed topic on Wall Street is Jane Street.

With 3,500 employees, no banking license, no consulting fees, and no investment-banking business. Relying solely on trading, in full-year 2025 they posted revenue of $39.6 billion. More than JPMorgan Chase. More than Goldman Sachs. More than any institution in Wall Street history.

Based on a 65–70% profit margin, the per-capita profit for this company is roughly $8 million to $9 million. Among companies with more than 1,000 employees, it ranks No. 1 in the world. Next door, Citadel Securities has 1,800 people, with per-capita profit of $3.6 million; Hudson River Trading is only $6.6 million; even Nvidia—an company that the entire world seems to be feeding money to—has per-capita profit of only $2.9 million.

So this week, all the finance professionals on Twitter have been talking about the same thing: how did Jane Street recruit this group of people?

The hardest company to get into on Wall Street

The name Jane Street isn’t unfamiliar in the crypto world.

SBF, the founder of FTX, got his first job in the form of an internship at Jane Street. SBF’s ex-girlfriend Caroline Ellison—the CEO who later left Alameda with a trail of chaos—also came from here. SBF later repeatedly mentioned in Michael Lewis’s book the market-thinking framework he learned at Jane Street, which nearly determined all of his trading instincts later when doing business at FTX and Alameda.

Many fund founders and project teams in crypto have had some overlap with Jane Street on their resumes before switching to crypto, but the vast majority of people only “interviewed” there, not “received an offer.”

Zhu Su, the founder of Three Arrows Capital, also tweeted to recall: “In December 2008, I interviewed at Jane Street in Tokyo and Hong Kong. A friend of mine worked at their Tokyo office—a PhD in architecture from the University of Tokyo who switched to quant trading. After my second round, I figured out one thing: I should learn programming, not mess around with Excel.”

A growth lead at the Monad Foundation retweeted a question he was asked in his second year at MIT, saying he “still remembers how crazy that interview was.” Glider Finance co-founder Brian is also chasing the discussion about the same long-circulating Jane Street cipher lock puzzle.

Many veteran players in the crypto space have brushed past this company at some point.

And the difficulty of interviewing at Jane Street is among the very highest across Wall Street. According to the tiering on the candidate interview difficulty list by Twitter user @vivoplt, Jane Street sits at the very top of the S+ difficulty level, tied with top AI labs.

A memory from a Twitter user named Hampton about a 2012 interview. Reading it feels a bit like black humor: they met around Financial District’s Fulton Street, next to an ATM from Bank of America by the World Trade Center. Then the interviewer took him onto the A-line subway, heading toward Central Park. He and the interviewer played chess in the subway—but with no board, just narrated. A coin toss decided whether the opening was 1.e4 or 1.d4. If by the 59th Street Columbus Circle there was still no decisive winner, they started a lightning match and kept playing all the way to Central Park. Hampton said he lost after just one stop at Times Square.

Another investor, Alex Song, recalled his Jane Street interview in 2010: “The worst interview I’ve ever had. One hour—the guy across from me explained some kind of card game rules, and I had to figure out the dominant winning strategy within an hour. This absolutely wasn’t something like a Putnam math competition, but it was worse than D.E. Shaw, QVT, and DRW.”

Another Twitter user who reposted it added a jab: this Alex later crushed it at Stanford undergraduate, did fixed-income trading at Morgan Stanley, fixed-income investing at Bain Capital, got an MBA from Harvard, worked at top hedge funds, and was an early-stage finance recruiting lead at Ramp—yet Jane Street didn’t hire him.

Some interviewees say: “To this day, it’s still the hardest interview process in investment banking. With other companies you can prepare, but with Jane Street, you really can’t prepare.” Even some netizens joke: “If Oppenheimer were still alive, I’d bet he still couldn’t pass Jane Street’s third-round interview.”

Tricky interview questions

Just hearing stories isn’t enough. Here are several questions that have been discussed repeatedly on Twitter. Rhythm’s editor picked a few of varying difficulty for readers to try and see how many they can solve.

Question 1: “Estimate how many windows there are in New York City. Explain your methodology.”

Question 2: “How many U.S. Marines would you estimate are needed to topple a major country in the Middle East?”

Question 3: “A safe has a six-digit code. The combination lock will tell you whether you’ve entered the correct four digits or more, but it will only truly open when all six are correct. What is the optimal strategy for finding the password with the fewest attempts?”

Question 4: “You have 30 real ropes in your hands (not strings from code). Randomly tie all 60 endpoints together in pairs—how many loops do you expect to form? Example: tying both ends of one rope = 1 loop; doing this with all 30 ropes = 30 loops. Tying the ends of two ropes together = 1 big loop; tying all 30 ropes together pairwise = 15 loops.”

Question 5: “After today, what is the next closest date where all digits are unique? Format DD/MM/YYYY. How confident are you?”

Question 6: “What integer is closest to the square root of 1420?”

Question 7: “What is the probability that one of my relatives is a professional baseball player?”

Question 8: “What is the smallest positive integer whose digits consist only of 1s and 0s and that is divisible by 15?”

Question 9: “At 3:15 PM, what is the angle between the hour hand and the minute hand of the clock?”

Question 10: “You have a chance to bid for a treasure chest. The treasure chest’s true value is some number between $0 and $1000, and you are 100% sure it’s within this range. If your bid is equal to or higher than the treasure chest’s true value, you get it at your bid; if your bid is lower, you get nothing. Meanwhile, you have a friend who is willing to buy it from you at 1.5 times its true value. How much should you bid?”

Question 11: “I roll a 20-sided die (numbers 1 to 20). How much would you pay to play this game, where the money you receive equals the number on the die? Now change the rules: in each round, you can choose either to ‘take the number showing on the current die’ or to ‘reroll once.’ There are 100 rounds in total. What is your optimal strategy? How much is this game worth?”

Question 12: “There are 100 statements written on a blackboard. Statement 1 says ‘At most 0 of these 100 statements are true.’ Statement 2 says ‘At most 1 of these 100 statements are true’… Statement n says ‘At most n−1 of these 100 statements are true.’ Statement 100 says ‘At most 99 of these 100 statements are true.’ Of these 100 statements, how many are actually true?”

Question 13: “I flip 4 coins—what is the expected value of the number of heads? Now you get one chance to re-flip all 4 coins (you must accept the new result). What does the expected value become?”

Question 14: “Two teams that are exactly equal in strength play a best-of-seven series. What is the probability that the series is decided only after Game 7?”

Question 15: “Suppose you and a roommate co-host a party, inviting 10 other pairs of roommates. During the party, you ask everyone except yourself: how many people have you shaken hands with? Given that no one has shaken hands with their own roommate, and that everyone’s answers are different, how many times did your roommate shake hands?”

Question 16: “100 prisoners are locked in 100 separate cells. The prison has only one light bulb room, and only one prisoner is allowed in at a time to turn the light on or off. Prisoners are called into the light bulb room randomly, with the number and order of visits completely out of anyone’s control. At any time, any prisoner can declare: ‘All 100 of us have already been in that room.’ If it’s correct, everyone is released; if it’s wrong, everyone is executed. Before the game starts, the prisoners can discuss a strategy, but after the game starts they cannot communicate. What is the optimal strategy?”

Question 17: “Suppose I have 10 coins. One is a fair coin (50% heads, 50% tails), and the other 9 are biased, but the degree of bias of each is unknown. With limited flips, how can you identify the fair coin?”

Question 18: “1000 ninjas stand in a circle, and each person holds a sword. Ninja #1 kills Ninja #2, Ninja #3 kills Ninja #4, Ninja #5 kills Ninja #6, and so on, continuing around the circle until only one person remains. Which number is that person?”

If you’ve made it through all the phone interviews, the final stage is called Super Day. When you enter, the staff will hand you 100 poker chips. Next comes 4 to 6 consecutive one-hour technical interviews, each with active traders facing you. In every session, you must place bets or market-make using those chips. SBF was told during his Super Day: “Anyone who loses all of their chips has never received an offer.”

What kind of people does Jane Street want

Augustin Lebron is a former trader at Jane Street who worked in the London office for many years and managed the internship program including SBF. After leaving Jane Street, he wrote a book called The Laws of Trading, and in an interview he said something extremely candid: “Globally, maybe only one or two thousand new people every year can get into truly good quantitative trading firms.”

“I’ve spoken with many students. If you ask them why they want to do this, they’ll say math is interesting, AI is interesting, statistics is interesting. But those skills can be applied elsewhere, so that alone doesn’t hold up.” But Augustin Lebron believes the real answers are usually two: first, it’s a high-status thing; second, they actually want to get rich.

So what kind of people does Jane Street recruit?

In the interview, Augustin Lebron said plainly that these firms recruit based on raw talent, not knowledge. That is, they pre-train people for this line of work—for example, people who have played poker, done sports betting, and really made money. Someone who has already gone through the experience of making decisions under uncertainty and bearing the economic consequences of those decisions.

And another very typical type of person is one who is eliminated quickly after joining, even if they’re extremely smart, very good at math, and excellent at solving problems—they just don’t like trading. They care more about solving the math problem than making money. “In trading, you ultimately have to make money.”

Some longtime Jane Streeters have also summarized several common reasons candidates fail: overconfidence; thinking silently—Jane Street places extreme emphasis on think out loud, and silent thinking is a big taboo; refusing to place bets—if you’re given a chance to market-make but you refuse, it’s essentially “you’re not willing to take risks”; and also, when you get stuck in a bad position, interviewers will deliberately give you extremely bad quotes—if you panic and accept, you prove that you shouldn’t have been hired. Ignoring hidden information in the questions, and so on.

And perhaps that’s exactly why Jane Street earns $40 billion a year.

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