Pro Securities Works: Services, Trading, and Key Facts
What Is Pro Securities?
Pro Securities was a U.S. financial-services company that operated as a FINRA-registered broker-dealer and owned and operated the PRO Securities alternative trading system (ATS), which was registered with the U.S. Securities and Exchange Commission (SEC). Its ATS provided a regulated electronic venue for matching buy and sell orders, rather than functioning as a traditional national securities exchange. The system was designed primarily for broker-dealer subscribers, and PRO Securities did not accept orders from non-broker-dealers or hold, own, or sell securities for its own account.
The company also became associated with the development of technology-driven securities trading through its relationship with tZERO and Overstock. SEC records show that PRO Securities was later known as tZERO ATS, LLC, reflecting its evolution within tZERO’s financial-technology operations. Historical SEC filings also document its role in after-hours trading and the development of infrastructure for trading certain digital securities.
How Pro Securities Worked
Pro Securities operated through an electronic trading system designed to bring together buy and sell orders from eligible broker-dealer participants. Instead of operating like a traditional public stock exchange, its alternative trading system provided a private marketplace where participating firms could submit orders for matching. This model allowed the platform to support securities transactions electronically while operating under the regulatory framework that applies to alternative trading systems. The system’s structure was particularly relevant to institutional and professional market participants seeking another venue for executing securities orders.
A key part of pro securities was its role as an intermediary in the trading process rather than as a conventional investment company. The platform’s function was to facilitate the matching and execution of orders submitted by participating broker-dealers. SEC records also described market-data services associated with the system, including information about the best available bids and offers and additional order-book depth. This combination of electronic order matching and market information made PRO Securities part of the broader evolution toward technology-based securities trading in the United States.
Pro Securities and Alternative Trading Systems
Pro Securities operated within the framework of an alternative trading system (ATS), a type of electronic marketplace regulated under U.S. securities law. An ATS can perform functions similar to a stock exchange by bringing buyers and sellers together, but it does not operate as a registered national securities exchange. The SEC explains that ATSs must follow the requirements of Regulation ATS, including broker-dealer registration and specified reporting and operational obligations. This structure allowed PRO Securities to provide an electronic venue for securities trading while operating under a different regulatory model from traditional exchanges.
Services and Trading Functions
Pro Securities provided electronic trading services through PRO ATS, using a fully automated electronic limit order book to match eligible buy and sell orders. Orders were submitted electronically through the FIX protocol and were generally matched according to price-time priority, meaning orders with better prices received priority and orders at the same price were generally prioritized according to the time they arrived. The system accepted limit-day orders, and unmatched orders remained on the order book until they were canceled, executed, or expired at the end of the trading session.
Another important function of pro securities was the publication and distribution of market data. PRO Securities provided real-time Level 1 data, including the best bid and offer, through its public website, while more detailed Level 2 data showing additional bids and offers was available through restricted access and direct data feeds. The SEC filing also describes PRO ATS as an overnight trading venue, with operating hours from 8 p.m. to 4 a.m. Eastern Time. These services helped participating firms monitor available liquidity and manage orders within the ATS.
PRO Securities, tZERO, and Overstock
Pro Securities became closely connected with tZERO and Overstock after Overstock acquired interests in the business as part of its expansion into technology-driven securities markets. PRO Securities operated its ATS as a regulated trading venue, while tZERO supplied technology supporting digital-security trading. Overstock’s digital preferred securities, including OSTKP and later OSTKO, were among the notable assets traded through the PRO Securities ATS, helping connect traditional securities infrastructure with blockchain-based financial technology.
The relationship also became significant because PRO Securities eventually operated within tZERO’s corporate structure. SEC records state that the company was formerly known as PRO Securities LLC, while tZERO ATS was a wholly owned subsidiary of tZERO Group, which itself was owned by Medici Ventures, a majority-owned subsidiary of Overstock. This history makes pro securities an important part of the development of tZERO’s early digital-securities trading platform.
Regulation, FINRA, and SEC Oversight
Pro Securities operated within a highly regulated U.S. securities framework. Historical SEC filings identify PRO Securities as an SEC-registered broker-dealer and a FINRA member, while its PRO Securities ATS was registered with the SEC as an alternative trading system. This meant the business was subject to regulatory examination, investigations, and potential disciplinary action by the SEC, FINRA, state securities regulators, and other applicable authorities.
The regulatory history also shows how the company evolved. FINRA records state that PRO Securities LLC was succeeded by the entity now known as tZERO Securities LLC in November 2019, while FINRA’s ATS records identify tZERO Securities as formerly PRO Securities and note that it ceased being an ATS-N filer in June 2021. SEC records likewise document the transition from PRO Securities to tZERO ATS.
The Evolution of Pro Securities
The history of pro securities reflects the broader shift from conventional electronic securities trading toward technology-driven and digital-asset markets. PRO Securities originally operated as a broker-dealer and alternative trading system, but its business later became integrated into the tZERO structure. FINRA records show that the firm was succeeded by tZERO Securities LLC on November 21, 2019, while SEC records identify the successor as formerly known as PRO Securities LLC.
This evolution became particularly significant as the platform expanded its role in trading digital securities. SEC records show that the ATS supported trading in tZERO security tokens and Overstock’s digital preferred securities, while the modern tZERO platform continues to operate a regulated ATS for digital asset securities. This progression illustrates how the original PRO Securities infrastructure became part of a broader effort to combine regulated securities markets with blockchain-based technology.
Key Facts and Industry Significance
Pro Securities was significant because it combined the functions of a regulated broker-dealer with an alternative trading system, giving eligible participants an electronic venue for matching securities orders. Its historical ATS was also used for after-hours ETF trading and for trading digital securities such as tZERO Preferred and Overstock Digital Preferred tokens. FINRA records confirm that PRO Securities LLC was succeeded by tZERO Securities LLC on November 21, 2019, marking an important transition in the company’s history.
Conclusion
The story of pro securities is closely connected to the development of alternative trading systems and blockchain-based securities markets in the United States. PRO Securities operated as a FINRA-registered broker-dealer and ran an SEC-registered ATS, providing an electronic venue for matching orders. Its history later became part of the tZERO structure, with FINRA records confirming that the firm was succeeded by tZERO Securities LLC on November 21, 2019.
Today, the name is best understood in a historical context rather than as a separate current company. SEC records identify the successor business as formerly known as PRO Securities, while current tZERO information describes tZERO Securities as an SEC-registered broker-dealer and FINRA member operating an ATS for digital asset securities. This evolution illustrates how the original pro securities platform became connected to newer approaches to electronic and tokenized securities trading.
FAQs
What was Pro Securities?
Pro Securities, LLC was a U.S. broker-dealer that operated an alternative trading system. FINRA records show that the firm was succeeded by tZERO Securities, LLC on November 21, 2019.
Is Pro Securities still a separate company?
No. The historical PRO Securities entity was succeeded by tZERO Securities. Current SEC records identify tZERO Securities, LLC as the broker-dealer entity, while tZERO operates an SEC-regulated ATS.
What did Pro Securities do?
PRO Securities operated an alternative trading system (ATS) that matched securities orders electronically. Historical SEC records also show that its ATS supported after-hours ETF trading and trading in certain digital security tokens.
What is the connection between Pro Securities and tZERO?
PRO Securities became part of the tZERO corporate structure and was eventually succeeded by tZERO Securities. Today, tZERO Securities operates the tZERO ATS and remains a SEC-registered broker-dealer and FINRA member.
