The LSE Directory / Prop firms
Jane Street is a New York headquartered quantitative trading and market making firm that provides liquidity across more than 200 electronic exchanges and venues worldwide. It trades equities, ETFs, fixed income, options, currencies, and commodities, using proprietary capital rather than managing money for outside clients. The firm describes its core activity as committing capital, technology, and quantitative research to help keep prices for the instruments it trades consistent and reliable, functioning as a counterparty for institutions, brokers, and other market participants rather than as an asset manager or advisor. Jane Street's specialisation is ETFs: the firm built its early business around ETF market making when the product was still a niche corner of the market, and by 2024 it was reported to handle a large share of daily bond ETF trading volume in the United States. It differs from many proprietary trading peers in that nearly all of its trading, research, and risk software is written in house in OCaml, a statically typed functional programming language, and the firm deliberately keeps its trading, research, and technology functions organisationally intertwined rather than siloed. It has no conventional single CEO; day to day leadership sits with a group of senior partners, and compensation is tied to firm wide profit rather than individual trader performance. The firm traces its roots to 1999, when former Susquehanna International Group traders Tim Reynolds, Robert Granieri, and Michael Jenkins, together with former IBM developer Marc Gerstein, started the business in a small New York office; it began operating and is commonly dated as Jane Street from 2000, consistent with the founding year the firm itself cites. Granieri is the only one of the four founders still at the firm as of 2026. Jane Street has grown to roughly 3,000 to 3,600 employees across offices that include New York, London, Amsterdam, Hong Kong, and Singapore, and holds regulatory authorisations including U.S. broker dealer registration, U.K. FCA authorisation, Netherlands oversight, and Hong Kong SFC regulation. It reported record quarterly results in the second quarter of 2025, with 10.1 billion dollars in net trading revenue and 6.9 billion dollars in net profit. In 2025 and 2026 Jane Street drew regulatory and legal scrutiny tied to its scale. India's Securities and Exchange Board barred the firm and its affiliates from Indian markets in July 2025, alleging manipulative expiry day trading in Nifty 50 and Bank Nifty index options after the firm earned an estimated several billion dollars from Indian index options trading between 2023 and 2025; Jane Street deposited funds in escrow and the trading restriction was subsequently lifted. Separately, in February 2026 the bankruptcy administrator for Terraform Labs filed a federal lawsuit in the Southern District of New York alleging insider trading and front running around the 2022 collapse of the TerraUSD stablecoin and LUNA token. Both matters were unresolved as of this research pass and are noted here as pending legal and regulatory actions rather than findings of wrongdoing.
