Put the firms side by side and a pattern falls out that should embarrass most of the industry. Renaissance banned Wall Street experience outright. D.E. Shaw staffed a hedge fund with scientists and produced Amazon and Two Sigma as side effects. Jane Street hires mathematicians who have never seen a market and teaches them a language no one else speaks. Susquehanna screens with poker. Four different firms, four different eras, one shared rule: do not hire people who already know your industry.

The logic is the same every time. Domain experience ships with domain conventional wisdom, and conventional wisdom is exactly the thing an edge has to beat. A trader who learned the old way has to unlearn it. A physicist arrives with no priors and a method that travels. Simons said it most plainly: easier to teach smart people markets than to teach market people to be smart. Shaw, Yass, and the Jane Street founders all built the same machine without coordinating, because the machine works.

What they actually select for

Strip away the surface and all four are screening for the same trait, just with different instruments. Renaissance reads your science. Jane Street reads your puzzles. SIG reads your poker. Shaw read your raw scientific ability and supplied the problem. None of them are testing whether you know the answer. They are testing whether you can find one in a domain you have never seen, which is the only ability that compounds when the domain keeps changing.

This is why the same firms now feed the AI labs. The trait that made a great quant in 1990 is the trait that makes a great researcher in 2026, because it was never about finance in the first place. The labs did not discover a new kind of talent. They recognized the old kind, sitting in trading firms, already pre-screened.

The recruiter's read, and the reason this blog exists: if you are hiring for a hard, undefined problem, the resume that already knows your industry is the weakest signal on the page, not the strongest. Hire the person who proved they can learn anything fast and think clearly under uncertainty, then teach them your world. Every firm on this list became one of the best at what it does by refusing to hire for what it does. That is not a paradox. It is the whole strategy.