Zeus

Jane Street made ~$40B in 2025 with 3,500 employees, a ~2x from the year before. At ~65-70% profit margin, that's $8M profit / employee, the highest for a 1000+ ppl company. High-frequency trading continues to be the most efficient money making engine. I want to share an old story about my Jane Street interview in 2014. Jane Street was known for hiring a lot of math, physics and CS olympiad winners from top universities and putting them through many rounds - including, for trading roles, a gauntlet of mental math. It was my 6th interview and my final round and I recall being asked "What is the next day after today in DD/MM/YYYY where all the digits are unique?" They'd toy with you and say "You can use a pencil and paper, if you want" but you knew that was an instant no. Painstakingly and as quickly as I could, I came to an answer. "How confident are you that this is correct on a 0-1 probability scale?" the interviewer said. "0.95", I blurted out, not fully knowing how to answer that. "Are you sure?" After thinking harder for a few more seconds, I realized I could've flipped the digits around to get a closer date. I gave the interviewer my answer. It was correct. "0.95 huh?" he chuckled. That's when I knew I failed. Note: fwiw, other companies that come close in efficiency are - Tether ($90M+ profit/emp) - Hyperliquid ($80M+ profit/emp) and on revenue: - Valve ($50M/emp) - OnlyFans ($37M/emp) - Craigslist ($14M/emp) - Anthropic ($12M/emp, run rate) - OpenAI ($8M/emp, run rate) For comparison, Nvidia is very efficient at scale and is $4.4M/emp.

What many of the replies in this thread have taught me: 1) There are a huge number of obnoxious people on here; I'm grateful that they've identified themselves so that I can mute them all easily. (I already knew this, but it's always eye-opening to see just how many stupid haters are out there). 2) People are truly desperate to believe that AI-driven software development at scale is a pipe dream that can never possibly work and seek out evidence, no matter how flimsy, to support this incorrect supposition. This is all going to end horribly for these people. And it's not just a few, it's probably at least half of the working professional software developers out there. They seriously believe that they're going to have to ride in like the hero cowboy and save the townspeople from all the AI code, and then everyone will clap. The reality is that these tools and approaches DO work, and the models are getting smarter by the month. And you only need one existence proof to show that, and then most companies will rush to adopt the proven methods. And once they do, they will lay off most of their developers and just keep the best ones who are most able to leverage these tools. The more hostile and annoying and dismissive you are about these inexorable technological and market forces, the more your neck is on the chopping block, and the people who run these big companies will be desperate to get rid of you not just to save the full cost of your salary and benefits, but to rid their company of the toxic negative attitude towards what they will rightly view as their primary strategic initiative. If you want to stay in this industry, you should open your eyes and stop being so stubborn. You are literally the equivalent of hand weavers in 1810 railing about those infernal machine looms. Within 20 years, they were all out of work and England had to pass the Frame Breaking Act because they had nothing better to do than try to burn down the new automated textile factories. Or don't, do whatever you want. But then I hope you have enough savings to get by with a sharply reduced income or some other skill you can use to earn money, because it's going to get very rough out there.