Went through the Jane Street PM process earlier this year. It's not widely documented because most people assume they don't hire PMs, but they do. It's a small function and the loop is different from big tech.
Context: I interviewed for an internal tooling PM role. Not a trading-adjacent product role. My sense is they have a few different PM tracks depending on what you'd be building.
Rounds I had: 1 product sense interview 1 strategy/business thinking interview 1 technical depth interview (with engineers, not PMs) 1 behavioral/culture interview 1 hiring manager conversation
Product sense: They gave me an internal tooling problem, asked me to think through how to prioritize competing needs across technical and business users. Not a "design an app for blind people" prompt. Very context-specific, expected you to ask clarifying questions.
Strategy: More like a case interview than a typical PM interview. They asked how I'd evaluate tradeoffs between build vs. buy for an internal tool. Expected me to structure the problem and think quantitatively.
Technical depth: Engineers asked me to walk through how I'd spec a feature, how I handle ambiguous technical requirements, and what I do when engineers push back on scope. This round is specifically checking whether you can work with highly technical people without handwaving.
What they care about for PM: Rigor. They don't want a PM who sells internally. They want someone who thinks clearly, acknowledges uncertainty, and knows when to defer to engineers. The PM culture there is closer to consulting than to growth-hacking.
Total process was about 7 weeks start to finish. Outcome: offer declined on my end (comp didn't work for relocation). Regret it a little.