Jane Street Capital


Jane Street Capital, typically referred to as Jane Street, is a global proprietary trading firm with around 900 employees.

Founding

Jane Street was co-founded by Tim Reynolds and three others. Jane Street's website says the firm was founded in 2000. However, Reynolds reports it to have been founded in 1999, although the date varies between sources.

Technology

Jane Street is,, one of only a few hundred businesses that use the OCaml programming language. It adopted OCaml as its main programming language early on because the language's functional programming style and clear expressiveness made it possible for code reviews to be performed by traders who were not programmers, to verify that high-performance code would do what it was intended to do. Jane Street has stated OCaml's advantages thus: “OCaml helps us to quickly adapt to changing market conditions, and go from prototypes to production systems with less effort”. Furthermore, OCaml's "rigor is like catnip to some people,... giving Jane Street an unusual advantage in the tight hiring market for programmers" that allows Jane Street to "lure a steady supply of high-quality candidates".
Jane Street has released some open source code on GitHub that includes their versions of standard OCaml libraries.