Just saw this lawsuit pop up and it got me thinking—how does a 3,000-person trading firm make more money than Citibank and Bank of America combined? Like, actually, how?

Jane Street Capital is one of those companies that barely anyone talks about until suddenly they're in the news for all the wrong reasons. Founded back in 1999 by traders who left Susquehanna, they started with something boring: arbitraging American Depositary Receipts. But then they made a bet on ETFs when nobody wanted them, and that single decision basically changed everything.

The numbers are honestly wild. In 2024, Jane Street Capital pulled in $20.5 billion in net trading revenue. Citigroup's entire trading division? $19.8 billion. Bank of America? $18.8 billion. A firm with 3,000 people just out-earned institutions with 200,000+ employees. And it gets worse—or better, depending on how you look at it. Bloomberg reported that in Q2 2025 alone they made $10.1 billion. Their first nine months of 2025 hit $24 billion, already beating their entire 2024 total.

What's their secret? They use OCaml, this obscure functional programming language that basically nobody else in finance touches. Their codebase is over 25 million lines—roughly half the size of the Large Hadron Collider's code. They have no CEO, just 30-40 senior partners who make decisions collectively. No non-compete agreements either. They hire based on one thing: can you solve problems under pressure? The internship posting everyone saw? $300,000 base for four months, zero finance background required.

But here's where it gets interesting. SBF—yes, that SBF—worked at Jane Street Capital for three years starting in 2014. He made $300,000 his first year, $600,000 the second, and $1 million bonus in the third. On election night 2016, he built a system that predicted voting outcomes faster than CNN. Jane Street shorted the market hard, had a $300 million paper profit by midnight, then watched it evaporate into a $300 million loss when markets rallied instead of crashed. They didn't fire him. They called his forecasting system accurate and his model sound—just a bad market read.

Then there's the India situation. In 2024, Jane Street Capital faced a bombshell: SEBI (India's SEC) investigated a strategy that made them over $1 billion in 2023 alone. The accusation? On Bank Nifty options expiration dates, Jane Street Capital allegedly bought massive amounts of stocks in the morning (sometimes 20%+ of daily volume), shorted options, then dumped everything in the afternoon to push prices down and cash in on their short positions. One day they lost $7.5 million on spot trades but made $89 million on options. SEBI found that from January 2023 to March 2025, Jane Street Capital made roughly $4 billion total in India while 93% of retail options traders lost money.

Then comes the Terra/Luna lawsuit. A Jane Street Capital employee named Bryce Pratt had been an intern at Terraform before joining the firm. He stayed in a private group chat with Terraform insiders. On May 7, 2022, Terraform quietly withdrew $150 million in UST from Curve. Ten minutes later, a Jane Street Capital wallet pulled $85 million from the same pool. Together they drained $235 million, breaking UST's liquidity support. Hours before the collapse, Jane Street Capital covered massive exposure. After UST crashed, Pratt messaged the Terraform team suggesting they buy Luna "at a significant discount."

Jane Street Capital denies everything. They call the India case "inflammatory" and the Terra lawsuit "transparent extortion." Fair points on some counts—Do Kwon did plead guilty to fraud. But that doesn't mean everyone else was innocent.

So what is Jane Street Capital really? It's a company that's simultaneously a marvel of engineering, a case study in information asymmetry, and apparently comfortable operating in some very gray areas. They describe themselves as "puzzle solvers." The market's starting to realize they might be solving puzzles in ways that raise uncomfortable questions.

The wild part? They're still mostly invisible. Most people have no idea that when they trade an ETF, there's probably a Jane Street Capital algorithm on the other side of that trade. That invisibility might be the biggest advantage of all.