Virtu files material amendments for POSIT and MatchIt covering real-time top-of-book data sent to its VET algorithms

The filings

Virtu Americas LLC (VAL), the broker-dealer that operates the POSIT and MatchIt alternative trading systems, has filed a Form ATS-N/MA for each venue. The “MA” suffix marks a material amendment. The SEC accepted the MatchIt filing at 8:32am ET on 29 October, although EDGAR gives its filing date as 28 October. The POSIT filing was accepted at 1:54pm ET on 29 October.

Each cover page includes a statement describing the amendment. The two statements are the same apart from the name of the ATS. The POSIT version reads:

“Changes are made to Part II Item 7a and 7b, as well as Part III Items 15b and 15c to add disclosures regarding anonymized, aggregated Top of Book Data that POSIT makes available to VET’s algorithms in real time. Changes are also made to Part III, Item 15b to state that data from the Conditional Session and Hosted Sessions is not provided to VET’s algorithms. Revisions to these items apply to the Broker Dealer Operator and all subscribers.”

VET is Virtu Electronic Trading. The current POSIT filing describes it as providing “algorithms that are used by clients and the Firm’s business units”. VET algorithms send orders to the ATSs as agent for clients, or as principal or riskless principal for other Virtu business units.

What the amendments change

The amendments touch four items on the form. Part II, Items 7a and 7b deal with how the operator protects confidential trading information and how subscribers consent to its disclosure. Part III, Items 15b and 15c deal with how order and trading-interest information is displayed or made known outside the matching engine, and whether that is the same for all subscribers.

The cover pages describe two changes:

• A new disclosure. Each ATS makes “anonymized, aggregated Top of Book Data” available to VET’s algorithms “in real time”.
• A stated limit. Data from the Conditional Session and Hosted Sessions “is not provided to VET’s algorithms”.

The cover pages do not say whether VET’s algorithms already receive this data, or whether the amendments describe a new data feed. They do not define “Top of Book Data”, and they do not give an implementation date.

Rule 304 of Regulation ATS requires an NMS Stock ATS to file a material amendment “At least 30 calendar days” before it implements a material change, with limited exceptions. The rule also covers changes to the activities of the broker-dealer operator or its affiliates that must be disclosed on the form. The filings do not explain how the 30-day requirement applies here.

What the current filings say

The current public versions of both forms predate these amendments: POSIT’s was filed on 4 May 2026 and MatchIt’s on 15 July 2026. Neither uses the term “top of book”.

Both say the firm does not treat data that “has been aggregated and which does not identify any Subscribers” as confidential information. Both say the firm publishes firm-wide aggregated, anonymous execution data to trade advertisement systems after trades are reported to the consolidated tape.

MatchIt’s current Item 15b says Firm-Up invitations from its Conditional Session, which include “the side, symbol, and quantity of the contra-side placement”, are “only sent to the algorithms of VAL and its Affiliates”. The new statement that Conditional Session data is not provided to VET’s algorithms refers specifically to the top-of-book data. The full amended text has not been published, so how the two statements fit together cannot yet be checked.

Only the cover pages are public

Each EDGAR filing currently contains a single public document, the cover page. Under Rule 304, the SEC makes the cover page of a material amendment public when it is filed, and the full amendment public once the review period ends, unless it declares the amendment ineffective. Until then, subscribers can see the summary but not the amended wording.

Why it matters

Analysis. Buy-side ATS due diligence usually turns on two questions. What does the operator do with my order information? Does the operator’s own trading business get anything other subscribers do not? Items 7 and 15 of Form ATS-N are where those answers sit. A real-time feed from the ATS to the operator’s algorithms falls in that territory, even if the data is aggregated and anonymised.

For market practitioners routing to POSIT or MatchIt, either directly or through VET algorithms, the questions to put to Virtu follow from the cover pages:

• What “Top of Book Data” includes.
• How it is aggregated and how often it is updated.
• When the algorithms started, or will start, receiving it.
• Whether it affects how VET algorithms route to Virtu’s ATSs compared with other venues.
• Whether direct subscribers can get the same data. Item 15c covers whether information is shared on the same terms with all subscribers.

What we are watching

• When the full amended text appears on EDGAR after the review period.
• Whether Virtu describes the top-of-book data as a new practice or as a more detailed description of an existing one.
• Whether other broker-operated ATSs file similar disclosures about data supplied to affiliated algorithms.