Two Sigma Securities, LLC (TSS) is the broker-dealer and electronic market-making affiliate of quantitative investment manager Two Sigma Investments, LP. It is registered as a broker-dealer with the SEC, is a member of the Financial Industry Regulatory Authority (FINRA) and the Securities Investor Protection Corporation (SIPC), and is a member of the major US equity exchanges. The firm operates a proprietary, high-performance trading platform that makes markets in more than 8,000 US exchange-listed equities and regularly executes over 300 million shares per day. Its business is organized around three activities: market making and intraday alpha generation in equities, futures and ETFs; options trading built on proprietary forecasting research; and a client-trading unit that offers wholesale market making, algorithmic execution, and single-dealer platform access to institutional counterparties. TSS competes in the electronic and wholesale market-making segment against firms such as Citadel Securities, Virtu Financial, Jane Street and Susquehanna. Its stated differentiator is applying its parent's data science and machine-learning research directly to quoting and execution, rather than running market making as a purely latency-driven business; the firm describes its approach as a "scientific approach to systematic trading." It serves both retail order flow (through broker-dealer clients) and institutional counterparties, and maintains offices in New York, Chicago, London, Tokyo, Hong Kong and Shanghai to support multi-region equity and derivatives market making. TSS was formed as a Delaware LLC and registered as a broker-dealer with the SEC in 2009 (FINRA CRD #148960, SEC file #8-68090), operating out of Two Sigma's New York headquarters at 100 Avenue of the Americas. In October 2017 it closed its acquisition of the US options market-making business of Timber Hill, the options market-making affiliate of Interactive Brokers Group, assuming roughly 1,300 exchange specialist assignments and using that business to expand into listed options across all US exchanges starting in 2018. Its parent, Two Sigma Investments, was founded in 2001 by John Overdeck and David Siegel (with early involvement from Mark Pickard) and managed approximately 70 billion dollars in assets as of 2025 with roughly 2,000 employees firm-wide. Two Sigma Investments underwent a leadership transition in August 2024, when co-founders Overdeck and Siegel stepped down as co-CEOs (remaining as co-chairmen) and were succeeded by Carter Lyons and Scott Hoffman; that change applies to the parent group's overall management rather than to any TSS-specific role disclosed in public sources.
