The LSE Directory / Prop firms
Hudson River Trading (HRT) is a quantitative trading firm headquartered in New York City that was founded in 2002 by a group of Harvard and MIT graduates with backgrounds in computer science and mathematics, among them Jason Carroll, who remains an active partner. HRT trades its own capital, not client or outside investor money, using automated algorithms it builds in house to price and execute across equities, futures, options, currencies and cryptocurrencies on more than 200 electronic markets and venues worldwide. The firm began with US equities and is now one of the largest electronic market makers in that asset class, and Wikipedia has cited estimates crediting it with more than 15 percent of daily US equities trading volume as of 2021. HRT differs from many high frequency trading peers in its mix of time horizons: alongside sub-millisecond market making it runs mid frequency strategies that can hold positions for days or weeks, and Wikipedia reports the firm has held around a quarter of its trading capital overnight rather than flattening every position by the close. Beyond pure proprietary trading, HRT also runs client facing execution services, a US Single Dealer Platform and, launched in 2018, a European Systematic Internaliser, plus a Client Market Making offering launched in 2022, putting it in competition with both other electronic market makers and bank execution desks for institutional order flow. The firm employs over 1,000 people across 14 offices spanning North America, Europe and Asia Pacific, including New York, Chicago, Austin, London, Dublin, Singapore, Shanghai, Mumbai, Seoul and Hong Kong. It grew its footprint through the January 2018 acquisition of rival market maker Sun Trading, and co-founded the Modern Markets Initiative, an industry group representing high frequency trading firms, in 2014. HRT was also examined in 2014 by the SEC and the New York Attorney General's office over questions about early access to market data and high frequency trading practices, part of a broader industry wide look at the sector at the time. As a private partnership, HRT does not publish audited financial results. HRT has leaned further into AI-driven research infrastructure: in 2026 it partnered with Lambda for access to NVIDIA HGX B200 accelerated computing for its research and development pipeline, and became a Visionary Sponsor of the Python Software Foundation, a tier it shares with firms including NVIDIA, Google and Meta. Press reporting in 2026, unverified by the firm itself since it does not disclose financials, has pointed to record quarterly trading revenue during a volatile period for markets.
