Form ATS-N/CA Files Dataset

The Form ATS-N/CA Files Dataset packages every Form ATS-N/CA correcting amendment accepted by EDGAR from July 2019 to present. Each record is one ATS-N/CA accession filed by the registered broker-dealer that operates an NMS Stock Alternative Trading System, submitted under Rule 304(a)(2)(i)(C) of Regulation ATS to fix information that was materially inaccurate or incomplete in a prior Form ATS-N filing. A record bundles the SEC-API metadata header, the canonical XML form payload, an XSL-rendered XHTML view of that payload, and any exhibit attachments the filer submitted — typically Schedule A of Form BD and Schedule B of Form BD and a redline against the prior version of the form. The dataset is distributed as monthly ZIP containers holding accession-numbered folders; the underlying file types are XML, PDF, JSON, and HTML, with image files stripped by design.

Dataset APIs

Dataset Files

What This Dataset Contains

The dataset captures the complete population of Form ATS-N/CA filings — the "correcting amendment" variant of Form ATS-N — submitted to the SEC's EDGAR system since the form first appeared on the wire in July 2019. Form ATS-N is the public disclosure that an NMS Stock ATS and its broker-dealer operator must file under Rule 304 of Regulation ATS to describe the manner of operation of the trading system, the activities of the operator and its affiliates that interact with the ATS, and the conflicts and informational-segregation arrangements around the system. An ATS-N/CA must be filed promptly upon discovery that information previously disclosed on Form ATS-N was materially inaccurate or incomplete at the time of that prior filing.

Each accession in the dataset is delivered as a folder inside a monthly ZIP container. The folder retains every document the filer submitted to EDGAR — the canonical XML form payload, the XSL-rendered human-readable view, and any exhibit attachments — except image files, which are stripped from the dataset. Coverage begins July 1, 2019, consistent with Regulation ATS-N's January 7, 2019 compliance date, and runs to present. Because the form has existed only under a single rulemaking regime, the part/item structure and the underlying ATS-N XML schema have been broadly stable across the dataset's coverage window — there is no ASCII-era body, no pre-XBRL versus post-XBRL transition, and no major item-numbering renumbering to navigate.

Content Structure of a Single Record

What one record represents

A single record in the Form ATS-N/CA Files Dataset is one Form ATS-N/CA submission accepted by EDGAR — a correcting amendment to a previously filed Form ATS-N filed by an NMS Stock Alternative Trading System under Rule 304(a)(2)(i)(C) of Regulation ATS. Each record is delivered as an accession-numbered folder inside a monthly ZIP container; the folder name is the 18-digit zero-padded EDGAR accession number with hyphens removed (for example, accession 0001767041-25-000009 becomes the directory 000176704125000009). The folder holds a SEC-API metadata header (metadata.json), the canonical XML form payload (primary_doc.xml), an XSL-rendered XHTML mirror of that same payload nested in an xslATS-N_X01/ subdirectory, and zero or more exhibit attachments (typically PDFs). Every file the filer submitted to EDGAR is preserved in the record except image files, which are stripped from the dataset by design.

What the underlying filing is

Form ATS-N/CA is the "correcting amendment" variant of Form ATS-N, the disclosure form an NMS Stock ATS and its broker-dealer operator must file to describe the manner of operation of the trading system, the activities of the operator and its affiliates that interact with the ATS, and the conflicts and informational-segregation arrangements around the system. An initial Form ATS-N (or an /UA "updating amendment" or /MA "material amendment") establishes or updates current disclosures; an ATS-N/CA must be filed promptly upon discovery that information previously disclosed on Form ATS-N was materially inaccurate or incomplete at the time of that prior filing.

Structurally the form body is identical to Form ATS-N — the same parts, items, schedules, and exhibits — but it is filed under the "/CA" submission type and adds a free-text statement identifying the items being corrected and explaining the prior inaccuracy or omission. Form ATS-N has been required for NMS Stock ATSs since the SEC's Regulation ATS-N rulemaking became effective in 2018, and the first /CA filings appeared on EDGAR from July 2019 onward.

Top-level content layers of one record

The record carries four logical layers, all rooted at the accession directory:

1. A SEC-API metadata header (metadata.json) capturing EDGAR-level filing metadata and a per-file inventory.
2. The canonical XML form payload (primary_doc.xml) conforming to the EDGAR ATS-N submission schema.
3. An XSL-rendered, human-readable view of the same form, stored as xslATS-N_X01/primary_doc.xml (XHTML despite the .xml extension).
4. Filer-supplied exhibit attachments (most commonly PDF), each corresponding to a numbered Form ATS-N exhibit slot.

The complete EDGAR .txt submission package referenced inside metadata.json.documentFormatFiles is not extracted into the record; only the per-document constituents are retained.

metadata.json shape

The metadata header is a single JSON object describing the filing as EDGAR accepted it:

• formType — fixed at "ATS-N/CA" for this dataset.
• accessionNo — EDGAR-assigned accession in hyphenated form (e.g., "0001767041-25-000009"); this is the authoritative identifier for the record.
• description — the standard EDGAR string "Form ATS-N/CA - Correcting Amendment to Form ATS-N (Rule 304(a)(2)(i)(C)): [Amend]".
• filedAt — ISO 8601 timestamp with US Eastern offset capturing the moment of acceptance.
• linkToTxt, linkToHtml, linkToFilingDetails, linkToXbrl — EDGAR URLs to the complete submission text, the index page, the XSL-rendered filing-details view, and the XBRL package respectively. linkToXbrl is empty because Form ATS-N/CA carries no XBRL.
• entities — array of filer entity objects. Each ATS-N/CA accession typically lists one filer (the broker-dealer operator) with cik, companyName (suffixed " (Filer)"), fileNo (the Form ATS file number, e.g., 013-00206), irsNo, stateOfIncorporation, fiscalYearEnd (MMDD), act ("34" for the Exchange Act), type (form type), and filmNo.
• documentFormatFiles — per-file inventory. Each entry has sequence, size (decimal byte count as a string), documentUrl, type, and optionally description. The canonical primary_doc.xml and the XSL-rendered view share sequence: "1" (the latter has its size blanked); each exhibit gets its own sequence; and the trailing entry — the complete .txt submission package — has a blank type and is not physically extracted into the dataset.
• seriesAndClassesContractsInformation and dataFiles — present but always empty for this form type.
• id — 32-character hex SEC-API record identifier.

The type values that appear on documentFormatFiles entries form the dataset's effective exhibit vocabulary: "ATS-N/CA" (the primary doc, listed twice — once for the canonical XML, once for the XSL-rendered view), "ATS-N EX-1 SCHD A BD", "ATS-N EX-2 SCHD B BD", and "ATS-N EX-3 REDLINE". The higher-numbered EX-4 (order routing / display information) and EX-5 (aggregate platform data) slots contemplated by the rule are typically absent on correcting amendments and are signaled as such by checkbox flags inside the form body.

primary_doc.xml — canonical form payload

The canonical XML conforms to the EDGAR ATS-N submission schema and carries the entirety of the structured form data. The outer <edgarSubmission> wrapper declares three namespaces — the form's own namespace (http://www.sec.gov/edgar/atsn), an EDGAR common namespace (com: prefix, used for filer credentials), and an atsncommon namespace (ats: prefix, used for shared sub-structures such as addresses and shared flags) — and contains exactly two children: <headerData> and <formData>. The XML carries no inline XSD reference; only the namespace declarations identify the schema.

<headerData>

The header block carries submission-level identification:

• submissionType — fixed at ATS-N/CA.
• accessionNumber — the filer-tool's pre-acceptance accession number, which is not necessarily the same as the EDGAR-assigned accession used for the folder name; consumers should key on metadata.json.accessionNo rather than this field.
• filerInfo — wraps liveTestFlag (LIVE or TEST), filer.filerCredentials.com:cik, filer.filerCredentials.com:ccc (always rendered as the masked literal XXXXXXXX), and filer.fileNumber (the Form ATS file number).
• filerInfo.flags — booleans ats:overrideInternetFlag and ats:confirmingCopyFlag, serialized as the strings "true" / "false".

<formData> — overall layout

<formData> is divided into a cover block and four numbered parts mirroring the printed Form ATS-N. Element local names embed both the part/item path and the input-widget type via short prefix conventions:

• rb* — radio-button single-select; value is typically Y or N.
• cb* — checkbox; value is true or false.
• tx* / txt* — short free-text input.
• ta* — long-form text area (multi-line narrative).
• part*Item* — wrapper elements that group a radio-button attribute with one or more child narrative elements.

Dates appear as MM/DD/YYYY strings rather than ISO format. Addresses are emitted via ats:street1, ats:city, ats:state, and ats:zip children inside the atsncommon namespace. Repeating values (multiple ATS trade names, multiple subscriber types, etc.) appear as sibling elements rather than as arrays.

Cover block

The <cover> element distinguishes the /CA variant. It carries txNMSStockATSName (the trade name of the alternative trading system, such as Bruce ATS or Citi-ONE ATS), an optional rbOperatesPursuantToFormATS flag (relating to legacy Form ATS coexistence), and most importantly taStatementAboutAmendment — the free-text narrative in which the filer identifies which items are being corrected and explains the material inaccuracy or omission in the prior filing. This narrative is the substantive payload that distinguishes a correcting amendment from a routine update or initial registration.

Part I — Identifying Information

Part I captures the identity of the broker-dealer operator and the ATS:

• Name of the broker-dealer operator and its CRD/SEC file numbers (txPart1Item4aBdFileNumber, etc.).
• One or more ATS trade names, encoded as repeated self-closing <atsName txPart1Item3ATSName="..."/> elements inside an <atsNames> wrapper.
• NMS Stock MPID (txtPart1Item5cNmsStockMPID) and effective membership date (part1Item5bEffectiveMembershipDate).
• Primary site address via part1Item7PrimarySite with the shared ats:-namespaced address children.
• Exhibit-presence checkboxes such as cbPart1Item8Exhibit1atWebsite and cbPart1Item9Exhibit2atWebsite, indicating whether Schedules A and B of Form BD are posted at a public website rather than attached to the filing.

Part II — Activities of the Broker-Dealer Operator and its Affiliates

Part II captures the operator's and affiliates' activities that touch the ATS and the conflicts they create. Items 1 through 7 cover, in order: trading activities of the broker-dealer operator on the ATS (Item 1), affiliate trading on the ATS (Item 2), order and trading information sharing and arrangements (Item 3), trading center arrangements (Item 4), other products and services offered (Item 5), service providers (Item 6), and protections of confidential trading information (Item 7). The recurring pattern is a parent wrapper element whose rb* attribute carries the radio-button answer and whose ta* child carries the explanatory narrative — for example, <part2Item5aDoesOfferProductsAndServices rbPart2Item5aDoesOfferProductsAndServices="Y"><taPart2Item5aProductsAndServices>...</taPart2Item5aProductsAndServices>...</part2Item5aDoesOfferProductsAndServices>.

Part III — Manner of Operations

Part III is the largest part of the form and the substantive description of how the ATS operates. It runs across roughly twenty-six numbered items covering, in order: subscriber types and eligibility, hours of operation, means of entry, connectivity, order types, order sizes, conditional orders, opening process, trading services, liquidity providers, segmentation, counter-party selection, display, routing, closing process, after-hours operation, fees, suspension, trade reporting, clearance and settlement, market data, order display, fair access, and aggregate platform data. Most items combine a narrative text-area answer (ta*) with structured radio-button or checkbox flags (rb*, cb*). Repeating taxonomic values — such as the categories of permitted subscribers — appear as repeated sibling elements (e.g., <taPart3Item1SubscriberType>Brokers</taPart3Item1SubscriberType>, <taPart3Item1SubscriberType>Principal Trading Firms</taPart3Item1SubscriberType>).

Part IV — Contact, signature, and consent to service

Part IV is the contact / signature / consent-to-service block contemplated by the form structure. The XSL-rendered view always includes a Part IV header, and the printed form devotes a final page to it. In practice, the Part IV element subtree may be sparsely populated or essentially empty in the canonical XML payload of correcting amendments because the substantive amendment narrative lives in the cover and in the corrected items.

XSL-rendered view (xslATS-N_X01/primary_doc.xml)

Each record contains a sibling subdirectory whose name encodes the EDGAR XSL stylesheet identifier (xslATS-N_X01, with capital X and hyphen). Inside it sits a file also called primary_doc.xml which is, despite its extension, an XHTML 1.0 Strict document — the human-readable rendering of the canonical XML that EDGAR serves at linkToFilingDetails. The XHTML references EDGAR's /css/ATSN_print.css stylesheet and image assets (/Images/radio-checked.jpg, /Images/box-unchecked.jpg) for the rendered radio-button and checkbox glyphs, and lays out the form values as inline text inside nested <div class="fakeBox">, fakeBox2, and fakeBox4 wrappers. A table of contents at the top links to anchors named #FilerInformation, #partI, #partII, #partIIitemN, #partIII, #partIIIitemN, and #partIV. The CCC remains masked (********) in the rendered view as well. Because both files are named primary_doc.xml, any tooling that flattens by basename will collide them unless the parent directory is preserved.

Exhibit attachments

Form ATS-N defines five numbered exhibit slots; the corresponding files appear at the root of the accession directory (alongside primary_doc.xml) when present. The exhibit roles, as encoded in metadata.json.documentFormatFiles[i].type, are:

• ATS-N EX-1 SCHD A BD — Schedule A of the broker-dealer operator's Form BD (a list of the operator's direct owners and executive officers).
• ATS-N EX-2 SCHD B BD — Schedule B of Form BD (indirect owners).
• ATS-N EX-3 REDLINE — a redlined comparison of the amended form against the prior version. This is the most consistently present exhibit on /CA filings and is the pragmatic way to inspect what the correction changed.
• ATS-N EX-4 — order-routing or display-information attachments contemplated by the rule.
• ATS-N EX-5 — aggregate-platform-data attachments contemplated by the rule.

Whether EX-1 and EX-2 attach to a specific filing or are instead posted on the operator's website is signaled by the cbPart1Item8Exhibit1atWebsite and cbPart1Item9Exhibit2atWebsite checkboxes inside primary_doc.xml. EX-4 and EX-5 are commonly absent on correcting amendments. Physical exhibit filenames are filer-supplied and not standardized — observed examples include lowercase descriptive names (scheduleaaa.pdf, schedulebbb.pdf, exhibit3.pdf) and date-stamped short codes (EX3CA20250708.pdf). The only reliable way to map a physical filename to an exhibit role is via the type field on the corresponding documentFormatFiles entry, not via the filename itself.

Included content

Each record includes:

• The SEC-API metadata header (metadata.json) with all submission and filer fields.
• The canonical XML form payload (primary_doc.xml) with full Part I–IV and cover content.
• The XSL-rendered XHTML view of the same payload at xslATS-N_X01/primary_doc.xml.
• All exhibit attachments submitted by the filer except image files. PDFs are preserved as native PDFs (verifiable by %PDF-1.x magic bytes); HTML exhibits, when present, are preserved at the accession-directory root.

The file-types found in the dataset are XML, PDF, JSON, and HTML, although in practice modern /CA filings consist of the XML pair, the JSON metadata header, and one or more PDF exhibits, with HTML exhibits being uncommon.

Excluded or structurally separate content

• Image files (GIF, JPG, PNG, etc.) carried in the original EDGAR submission are stripped from the dataset.
• The complete .txt submission package — the EDGAR-concatenated SGML wrapper that bundles every document — is referenced inside metadata.json.documentFormatFiles but is not physically extracted into the record; only the constituent documents are retained.
• The Filer Credentials Code (CCC) is masked to XXXXXXXX (canonical XML) or ******** (XSL view) in the source filings themselves and is never available in the data.
• No XBRL data files are present (linkToXbrl is empty and dataFiles is an empty array); Form ATS-N/CA does not carry XBRL.
• Schedules A and B of Form BD may be hosted on the operator's website rather than attached, in which case the relevant cbPart1Item*atWebsite checkbox is true and no EX-1/EX-2 file appears.

Interpretation notes

• Use metadata.json.accessionNo as the authoritative record identifier. The accessionNumber carried inside headerData of primary_doc.xml is the filer-tool's pre-acceptance accession and can differ from the EDGAR-assigned accession that names the folder.
• The documentFormatFiles array always carries a phantom trailing entry for the complete .txt submission package, with empty type and a sequence of " " (a literal space). This .txt is not in the record; ignore it when iterating actual files on disk.
• The canonical XML and the XSL-rendered XHTML share the filename primary_doc.xml. Preserve the parent directory (xslATS-N_X01/) when extracting or indexing, otherwise the rendered view will overwrite the canonical payload.
• The taStatementAboutAmendment element on the cover is the substantive description of what the correcting amendment fixes; for many analytical purposes it is the most important text in the record. The ATS-N EX-3 REDLINE PDF is the visual companion to that statement.
• Element local names are programmatically informative: the rb* / cb* / tx* / txt* / ta* prefix encodes the input-widget type, and the part1Item5b style suffix encodes the part/item path on the printed form. This makes XPath or regex extraction straightforward without an XSD.
• All filer credentials (CCC) are masked at source and cannot be recovered from the record.
• When EX-1 or EX-2 is missing, check the corresponding cbPart1Item*atWebsite flag in the canonical XML — a true value means the schedule lives on the operator's website rather than indicating a missing attachment.

Who Files or Publishes This Dataset, and When

Who files

Each record is one Form ATS-N/CA submitted to EDGAR by the broker-dealer that operates an NMS Stock Alternative Trading System (NMS Stock ATS). Under Regulation ATS, an ATS is not a separately registered entity; it is a trading system run by a registered broker-dealer that has elected to comply with Regulation ATS in lieu of registering as a national securities exchange under Section 6 of the Exchange Act. The filing therefore appears on EDGAR under the operator's CIK, not under a separate venue identity.

Filer population

Form ATS-N (and its amendment variants) applies only to:

• ATSs that trade NMS stocks, as defined in Rule 600 of Regulation NMS, and
• operators that are registered broker-dealers and SRO members (typically FINRA).

Out of scope: fixed-income, Treasury, municipal-securities, corporate-bond, and non-NMS OTC equity ATSs. Those venues remain on the legacy Form ATS / Form ATS-A / Form ATS-R regime under Rule 301(b)(2) of Regulation ATS, filed confidentially and not in this dataset. The in-scope population is narrow and well-defined: equity dark pools, institutional crossing networks, and bank-affiliated or independent NMS-stock ATSs.

Triggering event

Form ATS-N/CA is a correcting amendment required by Rule 304(a)(2)(i)(C) of Regulation ATS. It is triggered when the NMS Stock ATS discovers that information in a previously filed Form ATS-N or amendment was materially inaccurate or incomplete at the time it was filed.

The trigger is therefore:

• Backward-looking — it remedies a defect in a past disclosure, not a change in current operations.
• Discovery-based and event-driven — there is no schedule. An operator that never identifies a material defect never files an ATS-N/CA.
• Subject to a "promptly upon discovery" deadline — Rule 304(a)(2)(i)(C) requires filing promptly after the operator discovers the material inaccuracy or omission. No fixed numeric deadline is specified; "promptly" is interpreted in light of the SEC's adopting release (Release No. 34-83663, "Regulation of NMS Stock Alternative Trading Systems," July 18, 2018).

Regulatory framework

• Section 11A of the Securities Exchange Act of 1934 establishes the national market system underpinning NMS securities.
• Regulation ATS (17 CFR 242.300 et seq.), adopted in 1998 (Release No. 34-40760), lets ATSs operate as broker-dealers instead of registering as exchanges.
• Rule 304, added by Release No. 34-83663 (compliance date January 7, 2019), imposes the public Form ATS-N disclosure regime on NMS Stock ATSs and supersedes the legacy confidential Form ATS for that subset.
• Rule 304(a)(2) defines three amendment types, each with a distinct trigger:
  • ATS-N/MA — Material amendment, Rule 304(a)(2)(i)(A): forward-looking; filed at least 30 calendar days before implementing a material change to operations.
  • ATS-N/UA — Updating amendment, Rule 304(a)(2)(i)(B): periodic; filed by the end of each calendar quarter to update non-material drift.
  • ATS-N/CA — Correcting amendment, Rule 304(a)(2)(i)(C): backward-looking; filed promptly upon discovery of a material inaccuracy or omission in a prior filing. This dataset covers only ATS-N/CA.

Timing and cadence

ATS-N/CA filings are purely event-driven. There is no recurring cadence. A single discovery may produce one ATS-N/CA covering several corrections, or multiple ATS-N/CA filings as additional issues surface. Each filing identifies the specific Form ATS-N items being corrected, supplies the corrected disclosure, and explains the nature of the prior material defect.

The earliest ATS-N/CA filings appear in mid-2019, consistent with the January 7, 2019 compliance date and this dataset's July 2019 coverage start. The form did not exist before 2018 and has been EDGAR-native and public from the outset — a deliberate departure from the confidential legacy Form ATS regime.

Important distinctions

• Filer vs. venue. The EDGAR filer is the broker-dealer operator. The ATS itself is named within the form, not as a separate registrant.
• NMS Stock ATS only. Bond, Treasury, municipal, and non-NMS OTC equity ATSs file under Rule 301(b)(2) on Form ATS / ATS-A / ATS-R and are not in this dataset.
• ATS-N/CA vs. ATS-N/MA vs. ATS-N/UA. Same filer population, different triggers: planned material change (MA, 30 days advance), quarterly non-material update (UA), prompt correction of a prior material misstatement (CA).
• Materiality threshold. Only material defects trigger ATS-N/CA; non-material drift is handled via the quarterly ATS-N/UA. Materiality is judged in the first instance by the operator, subject to SEC oversight, which helps explain the modest ATS-N/CA volume relative to the broader Form ATS-N corpus.
• No effect on Form BD or FINRA records. ATS-N/CA amends only the public Form ATS-N disclosures, not the operator's broker-dealer registration or SRO membership records.
• No confidential variant. Form ATS-N and all its amendments, including ATS-N/CA, are publicly disseminated on EDGAR; the corrected disclosure enters the public record from the filing date forward.

How This Dataset Differs From Similar Datasets or Filings

Form ATS-N/CA sits inside a tightly bounded family of Regulation ATS filings. The useful comparisons fall along two axes: the ATS-N amendment family (MA, UA, CA, CES, OFA) that all attach to a parent Form ATS-N, and the parallel Form ATS / Form ATS-R regime covering non-NMS ATSs. Each form is distinguished by its trigger, its time direction (forward- vs. backward-looking), and the asset class of the ATS that files it.

Form ATS-N (initial disclosure)

Form ATS-N is the foundational public disclosure filed under Rule 304 by an NMS Stock ATS and its broker-dealer operator. It establishes the full baseline record: manner of operations, conflicts, order types, subscriber categories, fees, segmentation, market data usage, and operator activities. ATS-N/CA is not standalone — it presupposes a prior ATS-N and carries only the corrections needed to fix material inaccuracies or omissions that were present in that prior filing when made. ATS-N is structural and comprehensive; ATS-N/CA is narrow, surgical, and meaningless without its parent.

Form ATS-N/MA (material amendments)

ATS-N/MA is forward-looking: it announces a material change in the ATS's manner of operations, filed at least 30 calendar days before implementation and subject to Commission review. ATS-N/CA is backward-looking: it does not announce any change in operations, but corrects information that was wrong or incomplete when previously disclosed. MA reflects evolution of the venue itself; CA reflects defect in prior reporting. Conflating the two would mix genuine operational change with disclosure cleanup.

Form ATS-N/UA (updating amendments)

ATS-N/UA updates information that has changed since the last ATS-N filing but does not rise to a material operational change (e.g., revised affiliate information, non-material fee adjustments). Like CA, it amends an existing ATS-N record, but the trigger differs sharply: UA captures a real-world change that is not material; CA fixes an error in prior disclosure of facts that may not have changed at all. UA is forward- or contemporaneous-looking on facts; CA is retrospective on disclosure quality.

Form ATS-N/CES and Form ATS-N/OFA

Form ATS-N/CES is the cessation notice filed when an NMS Stock ATS stops operating as such, terminating the ATS-N reporting obligation. Form ATS-N/OFA relates to the Commission's order finding an amendment ineffective. Both mark end-of-life or adverse-action events. ATS-N/CA, by contrast, is part of routine maintenance of an active venue's disclosure record. CES datasets are small and tied to shutdowns; CA captures continuing-operation corrections by ATSs that remain in business.

Form ATS (non-NMS ATSs)

Form ATS is the older, largely confidential initial-operation report filed under Rule 301(b)(2) by ATSs trading non-NMS securities (fixed income, OTC equity, other instruments). The filer populations only partially overlap — an operator running both an NMS Stock ATS and a non-NMS ATS files in both regimes — but the regimes diverge on public disclosure, content template, and amendment mechanics. Corrections to Form ATS flow through Form ATS amendments under Rule 301, not through anything analogous to ATS-N/CA.

Form ATS-R (quarterly activity report for non-NMS ATSs)

Form ATS-R is a recurring quantitative report under Rule 301(b)(9): volume, transaction counts, and securities traded by non-NMS ATSs each quarter. ATS-N/CA is event-driven and narrative, correcting qualitative disclosures of how a venue operates. The two answer different questions: ATS-R asks "how much trading happened"; the ATS-N family asks "how does this venue work and who controls it."

Boundary summary

Two boundary criteria isolate Form ATS-N/CA:

1. Asset class — The entire ATS-N family (including CA) applies only to NMS Stock ATSs. Form ATS and Form ATS-R cover non-NMS ATSs under a separate, largely confidential, partly quantitative regime, and do not overlap with this dataset at all.
2. Trigger within the ATS-N family — ATS-N is the original disclosure; MA covers prospective material operational changes; UA captures non-material real-world changes; CES and OFA mark cessation and adverse Commission action; CA is uniquely retrospective, addressing only errors or omissions in what was previously filed.

ATS-N/CA is therefore best paired with the parent ATS-N and with sibling MA and UA filings to reconstruct an ATS's currently effective disclosure. It is not a substitute for any of them, and has no counterpart in the non-NMS Form ATS / ATS-R regime.

Who Uses This Dataset

The readership of the Form ATS-N/CA Files Dataset clusters around equity market-structure analysis, broker-dealer compliance, and venue due diligence. Each profession reads the same filings for different fields — most often the corrected items, the materiality explanation, the affiliate schedule, and the restated manner-of-operations text.

Market structure researchers and academic economists

Researchers studying dark pools behavior, off-exchange liquidity, and venue toxicity treat these filings as primary evidence of how ATSs actually operate when stated practices change after the fact. They focus on which Part III items were corrected (order types, segmentation, subscriber tiers, fees, conflicts) and the operator's explanation of the inaccuracy. Outputs include event studies linking correcting amendments to shifts in market share, fill rates, and adverse selection.

Buy-side execution and best-execution committees

Equity execution traders and best-ex committees at asset managers and pension plans revalidate counterparty due diligence on routed venues. They focus on corrections to subscriber categories, order interaction rules, information leakage controls, and affiliate access, since these change whether an ATS still matches the venue profile assumed in routing logic. Workflow outputs: updated venue scorecards, best-execution review memoranda, and decisions to add, restrict, or drop an ATS.

Transaction cost analysis and execution consulting teams

TCA providers and execution consultants ingest restated descriptions of order types, anti-gaming logic, segmentation, and matching priority to keep venue taxonomies current. The corrected text and the operator's explanation drive updates to venue profiles, benchmarking reports, and routing guidance for institutional clients.

Broker-dealer compliance officers and ATS operators

Compliance staff at firms operating or planning an NMS Stock ATS benchmark peer drafting against Rule 304(a)(2)(i)(C). They focus on which items peers correct, how the materiality determination is framed, and the depth of the explanation, using these as references when drafting their own amendments and internal training on Regulation ATS.

Securities lawyers and Regulation ATS counsel

Outside counsel and in-house securities lawyers advising ATS operators study the explanation section, redlined Part III items, and schedule of affiliates, especially when corrections touch affiliate access, conflicts, or material agreements. The dataset supports drafting correcting amendments, responding to SEC staff comments, and opining on whether an identified error meets the ATS-N/CA threshold.

Regulators, SRO examiners, and policy staff

Examination and policy staff at securities regulators and SROs use the corpus to target sweeps and inform rulemaking. They focus on the frequency and substance of corrections, repeat offenders, and the gap between the underlying inaccuracy and disclosure. Outputs include risk-based examination targeting, aggregate statistics in policy reports, and supervisory letters on recurring disclosure weaknesses.

Venue reference data and SOR vendors

Firms maintaining trading-venue reference data and smart-order-router rule sets track corrected operational specifications, order type definitions, hours, segmentation tiers, and fee/rebate descriptions to keep venue metadata accurate. The dataset feeds automated updates to venue profile tables and SOR configuration logic.

Surveillance and best-execution monitoring vendors

Vendors building surveillance, trade reconstruction, and best-execution tools align venue logic to the corrected descriptions of order interaction, matching, and affiliate access. Outputs include updated venue rule libraries, recalibrated alerts for layering, spoofing, and internalization, and audit trails showing alignment with current disclosures.

Conflicts and governance analysts

Analysts evaluating broker-dealer conflicts focus on the schedule of affiliates, manner-of-operations text, and any correction touching conflicts disclosures, particularly around internal routing and segmentation that may favor proprietary flow. Outputs feed into broader broker-dealer conflict assessments and stewardship reviews.

Data engineers and RAG/LLM developers

Engineering teams building market-structure datasets and developers training retrieval systems on regulatory text use the XML and HTML filings plus the metadata index as a tightly scoped corpus. The consistent identification, corrected-items, and explanation sections make it suitable for fine-tuning extractors, linking ATS operators to broker-dealer parents, and powering QA systems on ATS operations.

Litigation support and expert witnesses

Expert witnesses and litigation teams in best-execution, ATS conduct, or misrepresentation matters use the explanation of the inaccuracy, the timing relative to the original Form ATS-N, and the substantive redline as documentary evidence in expert reports, deposition exhibits, and damages analyses.

Specific Use Cases

The following workflows show how analysts, compliance staff, and engineering teams use Form ATS-N/CA records in practice. Each ties a specific dataset element to a definite output.

Reconstructing the currently effective ATS-N disclosure for a venue

Best-execution committees and TCA teams maintaining venue profiles for dark pools (e.g., Bruce ATS, Citi-ONE ATS) merge each operator's parent ATS-N with all subsequent /UA, /MA, and /CA filings to derive a single effective description. The taStatementAboutAmendment cover narrative tells the consumer which Part III items the /CA actually overwrites; the ATS-N EX-3 REDLINE PDF shows the changed text line by line. The output is an updated venue profile entry feeding routing logic and best-ex scorecards.

Targeting examination sweeps on disclosure-quality outliers

SRO examiners and SEC policy staff aggregate /CA filings across operators to flag repeat correctors and slow corrections. They key on metadata.json.accessionNo and filedAt, the cited Part/Item paths in taStatementAboutAmendment, and the gap between the original ATS-N filing date and the /CA acceptance timestamp. The output is a risk-ranked operator list for targeted ATS sweeps and supervisory letters on recurrent Part III drafting weaknesses.

Drafting peer-benchmarked correcting amendments

Outside counsel and in-house Regulation ATS lawyers preparing a /CA for a client pull the taStatementAboutAmendment text and the EX-3 redline from prior peer /CA filings to benchmark how peers frame materiality, scope the corrected items, and describe the underlying error. They reuse phrasing patterns and the level of operational detail as drafting references when scoping their own filing under Rule 304(a)(2)(i)(C).

Updating SOR rule sets after order-type or segmentation corrections

Smart-order-router and venue reference-data vendors monitor incoming /CA filings for corrections to Part III items covering order types, conditional orders, segmentation, counter-party selection, and routing. Because element local names embed the part/item path (part3Item*, taPart3Item1SubscriberType, etc.), an XPath extractor against primary_doc.xml can detect changes to these specific items without manual review. The output is a queued change ticket against venue metadata tables and SOR configuration entries.

Building affiliate and ownership graphs of NMS Stock ATS operators

Conflicts analysts and data engineers extract the ATS-N EX-1 SCHD A BD (direct owners and executive officers) and ATS-N EX-2 SCHD B BD (indirect owners) PDFs, plus the cbPart1Item8Exhibit1atWebsite / cbPart1Item9Exhibit2atWebsite flags that indicate when the schedules live on the operator's website. Cross-referenced with the entities[].cik and fileNo fields in metadata.json, this yields an ATS-to-broker-dealer-parent ownership graph used in conflicts reviews of internalization and proprietary flow access.

Documentary evidence in best-execution and misrepresentation litigation

Expert witnesses and litigation teams use the taStatementAboutAmendment narrative and the ATS-N EX-3 REDLINE exhibit as direct evidence that a specific operational fact was misstated during a defined window — bounded by the original ATS-N filing and the /CA filedAt timestamp. These items become deposition exhibits and anchor damages analyses tied to routing decisions made under the prior, inaccurate disclosure.

Fine-tuning extractors and RAG systems on Regulation ATS text

Engineering teams building retrieval systems on market-structure regulation use the XML/XHTML pair plus the JSON metadata header as a tightly scoped, schema-stable corpus. The consistent rb*/cb*/ta* widget-prefix naming, the predictable part/item suffixes, and the bounded exhibit vocabulary (ATS-N EX-1 SCHD A BD, EX-2 SCHD B BD, EX-3 REDLINE) make the dataset usable for training item-level extractors and powering QA over ATS manner-of-operations text without an XSD.

Dataset Access

The Form ATS-N/CA Files Dataset is available through three access methods: a JSON metadata API, a full dataset archive download, and individual monthly container downloads. Containers are distributed as monthly ZIP archives, each holding per-accession folders with the original EDGAR submission documents in XML, PDF, JSON, and HTML formats (image files excluded).

Dataset Index JSON API: https://api.sec-api.io/datasets/form-atsn-ca-files.json

Returns dataset-level metadata (name, description, last update timestamp, earliest sample date, total records, total size, form types, container format, file types) along with the full list of monthly container files and their individual download URLs, sizes, record counts, and update timestamps. Use this endpoint to monitor which containers were refreshed in the most recent run and decide which ones to fetch incrementally. This endpoint does not require an API key.

Example response:

          1
          {
        

          2
            "datasetId": "1f13365b-9ae0-6a07-a163-827dbdac9480",
        

          3
            "datasetDownloadUrl": "https://api.sec-api.io/datasets/form-atsn-ca-files.zip",
        

          4
            "name": "Form ATS-N/CA Files Dataset",
        

          5
            "updatedAt": "2026-05-02T03:01:23.822Z",
        

          6
            "earliestSampleDate": "2019-07-01",
        

          7
            "totalRecords": 692,
        

          8
            "totalSize": 86560448,
        

          9
            "formTypes": ["ATS-N/CA"],
        

          10
            "containerFormat": "ZIP",
        

          11
            "fileTypes": ["XML", "PDF", "JSON", "HTML"],
        

          12
            "containers": [
        

          13
              {
        

          14
                "downloadUrl": "https://api.sec-api.io/datasets/form-atsn-ca-files/2026/2026-03.zip",
        

          15
                "key": "2026/2026-03.zip",
        

          16
                "size": 1842331,
        

          17
                "records": 6,
        

          18
                "updatedAt": "2026-05-02T03:01:23.822Z"
        

          19
              }
        

          20
            ]
        

          21
          }
        

Download Entire Dataset: https://api.sec-api.io/datasets/form-atsn-ca-files.zip?token=YOUR_API_KEY

Downloads the complete dataset (all ATS-N/CA filings from July 2019 to present) as a single ZIP archive. This endpoint requires an API key.

Download Single Container: https://api.sec-api.io/datasets/form-atsn-ca-files/2026/2026-03.zip?token=YOUR_API_KEY

Downloads one monthly container ZIP, which expands into per-accession folders containing the metadata file and original submission documents for each filing in that month. Use the container key values from the JSON index to construct other monthly URLs. This endpoint requires an API key.

Frequently Asked Questions

What form does this dataset cover?

The dataset covers Form ATS-N/CA, the "correcting amendment" variant of Form ATS-N. It is filed pursuant to Rule 304(a)(2)(i)(C) of Regulation ATS to fix information that was materially inaccurate or incomplete in a previously filed Form ATS-N.

What does one record in this dataset represent?

One record is a single Form ATS-N/CA submission accepted by EDGAR, packaged as an accession-numbered folder containing a metadata.json header, the canonical primary_doc.xml form payload, an XSL-rendered XHTML view of that payload at xslATS-N_X01/primary_doc.xml, and any exhibit attachments the filer submitted (typically Schedule A and Schedule B of Form BD and a redline). The 18-digit zero-padded EDGAR accession number names the directory and serves as the authoritative record identifier via metadata.json.accessionNo.

Who is required to file Form ATS-N/CA?

The filer is the registered broker-dealer that operates an NMS Stock Alternative Trading System. The form applies only to ATSs that trade NMS stocks under Rule 600 of Regulation NMS and whose operators are registered broker-dealers and SRO members (typically FINRA). Non-NMS ATSs (fixed income, Treasury, municipal securities, OTC equity) file under the separate, largely confidential Form ATS / ATS-A / ATS-R regime and are not in this dataset.

When must an ATS-N/CA be filed?

Filing is event-driven, not periodic. The trigger is the operator's discovery that a previously filed Form ATS-N or amendment was materially inaccurate or incomplete at the time it was filed. Rule 304(a)(2)(i)(C) requires the filing be made promptly upon discovery; no fixed numeric deadline is specified.

How does ATS-N/CA differ from ATS-N/MA and ATS-N/UA?

All three are amendments to a parent Form ATS-N filed by the same broker-dealer operator population, but their triggers diverge. ATS-N/MA is forward-looking and announces a planned material change, filed at least 30 calendar days before implementation. ATS-N/UA is a periodic, quarter-end update for non-material drift. ATS-N/CA is uniquely retrospective and corrects errors or omissions in what was previously filed.

What time period does the dataset cover?

The dataset begins July 1, 2019, the month the first Form ATS-N/CA filings reached EDGAR following Regulation ATS-N's January 7, 2019 compliance date, and runs to the present. There is no pre-2019 history because the form did not exist before that rulemaking.

What file format is the dataset distributed in?

The dataset is distributed as monthly ZIP containers. Inside each container, every accession is a folder containing files in XML, PDF, JSON, and HTML formats. Image files are stripped, and the EDGAR-concatenated .txt submission package is referenced inside metadata.json.documentFormatFiles but not physically extracted.