The Form UNDER Files Dataset is a complete archive of Form UNDER and Form UNDER/A submissions accepted by SEC EDGAR from June 2000 to the present. Each record corresponds to a single Form UNDER filing — a short, freestanding written undertaking by a registered investment company committing to file specified documents or information by post-effective amendment to a Securities Act of 1933 registration statement, most commonly a Form N-14 fund reorganization. A record bundles the EDGAR submission header as structured JSON together with the SGML-wrapped HTML document containing the cover transmittal letter and the operative undertaking language. Filings are grouped into monthly partitions and distributed as ZIP containers, with internal artifacts in TXT, JSON, and HTML formats. The dataset is a precedent and reconciliation resource for fund counsel, compliance teams, and EDGAR researchers working on the procedural side of investment-company registration.
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The dataset captures every Form UNDER and Form UNDER/A filing submitted to EDGAR since June 2000, presented in its native EDGAR form. Form UNDER is a short ancillary submission used by registered investment companies in connection with Securities Act of 1933 registration statements, most commonly Form N-14 (registration of securities by investment companies for business combinations and reorganizations) and historically Form S-6 (unit investment trust registration). The filing is a formal written undertaking by the registrant promising to file specified documents or information by post-effective amendment after the related registration statement becomes effective. The undertaking exists because portions of the registration package — final tax opinions, executed agreements, closing-contingent items — are not available when effectiveness is requested. By committing to supply them later via post-effective amendment, the registrant satisfies the Commission's disclosure expectations without delaying acceleration of effectiveness of the parent registration.
Form UNDER/A is the amendment variant, used when a previously submitted undertaking must be modified. The document and metadata structures are identical to an initial UNDER; only the formType value and the EDGAR-assigned accession number differ. Form UNDER is a niche filing type with low overall submission volume, so many monthly partitions contain few or no records; consumers should not infer dataset gaps from empty months. The dataset preserves the full EDGAR submission for each filing — the structured filing-header metadata and the substantive HTML undertaking document — while excluding image files such as letterhead logos and scanned signatures that may have accompanied the original submission.
A single record in the Form UNDER Files Dataset corresponds to one Form UNDER or Form UNDER/A submission accepted by EDGAR, identified uniquely by its accession number. Physically, each record is a folder named after the accession number with dashes stripped (for example 000095012311068501, corresponding to canonical accession 0000950123-11-068501). Inside that folder sit two artifacts: a metadata.json file describing the EDGAR submission header, and the Form UNDER document itself — an HTML file wrapped in the EDGAR SGML document envelope. Filing folders are grouped under a monthly partition (for example 2011-07/) and distributed as monthly ZIP containers.
Each record therefore captures the full payload of one undertaking filing: the structured header metadata derived from the SGML submission, and the substantive undertaking letter as filed by the registrant. Because Form UNDER is a single-document form with no exhibit list, each record's filesystem footprint is small — one metadata.json and one .htm document, typically a few kilobytes in total.
Every record has two parallel content layers:
metadata.json. A single JSON object summarizing the EDGAR submission header — form type, accession number, filing timestamp, registrant identifiers, the parent-registration file number, the list of attached documents, and URLs back to the EDGAR-hosted originals..htm file containing the actual Form UNDER. The filename is whatever the registrant uploaded to EDGAR; a frequent convention is <prefix>under.htm (for example y91889uunder.htm, y91890uunder.htm), but no dataset-wide naming rule is enforced.Image files that may have been part of the original EDGAR submission (letterhead logos, scanned signature images) are excluded from the dataset. All other components of the Form UNDER submission are preserved.
metadata.json objectThe metadata file describes the filing at the EDGAR-header level. The fields are:
formType — UNDER for an initial undertaking or UNDER/A for an amendment.accessionNo — the canonical dashed EDGAR accession number, e.g. "0000950123-11-068501".filedAt — the acceptance timestamp in ISO 8601 with timezone, e.g. "2011-07-26T18:45:13-04:00".description — the free-text filing description supplied via EDGAR, typically of the form "Form UNDER - Undertaking to file reports, [Item 4 Form S-6]", which names the SEC rule item and the parent form to which the undertaking attaches.linkToFilingDetails — URL to the primary Form UNDER document on sec.gov.linkToTxt — URL to the full submission text bundle on sec.gov.linkToHtml — URL to the EDGAR filing index page for the accession.linkToXbrl — an empty string; Form UNDER does not carry XBRL data.documentFormatFiles[] — an array of objects, one per attached document. Each entry has sequence, size, documentUrl, description, and type. Typically the array holds two entries: the Form UNDER document itself (type: "UNDER") and the complete-submission text wrapper that EDGAR generates for every filing.dataFiles — an empty array, since Form UNDER has no XBRL or data attachments.seriesAndClassesContractsInformation — an array reserved for investment-company series/class identifiers; empty in observed records.entities[] — an array of filer entity objects. Each entry describes one filer with fields such as cik, companyName (with a parenthetical role suffix such as (Filer)), irsNo, fileNo (the 333- Securities Act file number of the parent registration), filmNo, act (the Securities Act identifier, typically "33"), fiscalYearEnd, optional stateOfIncorporation, type (the form type for this filer's role), and a tickers array when ticker symbols are known.id — an internal content-hash identifier.The fileNo field on each entity is interpretively the most important field beyond the accession number: it is the registration-statement file number that this undertaking is linked to. An UNDER filing carrying fileNo: "333-174294" was submitted in support of the Securities Act registration statement bearing that number.
A representative entity block looks like this:
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{
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"fiscalYearEnd": "1231",
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"stateOfIncorporation": "MD",
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"act": "33",
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"cik": "0000845611",
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"fileNo": "333-174294",
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"irsNo": "133523423",
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"companyName": "GABELLI CONVERTIBLE & INCOME SECURITIES FUND INC (Filer)",
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"type": "UNDER",
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"filmNo": "11988456",
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"tickers": ["GCV"]
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}
Most Form UNDER records contain exactly one filer entity, but entities[] is structurally an array and can carry several entries when more than one registrant is named on the undertaking. stateOfIncorporation is optional. The tickers array may be empty, hold a single symbol, or hold several share-class or exchange-suffix variants (for example ["GDV", "GDV.PH", "GDV.PK"] for a Gabelli closed-end fund with multiple listed tranches).
The .htm file in each record is the EDGAR-submitted document, but it is not raw HTML at the top level — it is HTML wrapped in the EDGAR SGML document envelope. The leading lines follow a standardized shape:
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<DOCUMENT>
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<TYPE>UNDER
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<SEQUENCE>1
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<FILENAME>y91889uunder.htm
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<DESCRIPTION>UNDER
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<TEXT>
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<HTML> ... full HTML body ... </HTML>
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</TEXT>
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</DOCUMENT>
The <TYPE>, <SEQUENCE>, <FILENAME>, and <DESCRIPTION> lines are SGML header fields that mirror the corresponding entries in documentFormatFiles[]. Everything between <TEXT> and </TEXT> is the substantive content rendered as HTML.
Inside the HTML body, a typical Form UNDER follows a two-page structure:
<!-- PAGEBREAK --> HTML comment, this page sits on the registrant's letterhead and contains the operative undertaking language. The wording is typically a single paragraph along the lines of "The Registrant hereby undertakes that it will file a post-effective amendment to its Registration Statement if it determines to conduct a rights offering..." or referring to other contingent disclosures. The page closes with a signature block, conventionally rendered as /s/ <Name>, <Title> (for example /s/ Agnes Mullady, Treasurer and Secretary).The substantive wording of the undertaking varies because each one is drafted by the registrant's counsel for the specific transaction; only the SGML wrapper and the EDGAR header conventions are uniform across records.
A record includes the full EDGAR submission for the Form UNDER filing in its native form: the structured filing-header metadata, the SGML-wrapped HTML document containing the cover letter and undertaking, the registrant identifiers, the linked registration-statement file number, the filing timestamp, and the document-attachment manifest. Direct URLs back to sec.gov are preserved on every record for cross-reference to the EDGAR-hosted originals.
Image files that may have been part of the original EDGAR submission — embedded letterhead logos, scanned signatures, graphic elements — are excluded from the dataset; signatures therefore appear in the HTML as /s/ <Name> text marks rather than as image scans. The related registration statement (typically the N-14 or, historically, S-6) is a separate EDGAR filing under its own accession number and is not part of the Form UNDER record. The fileNo field on each entity is the bridge that links a record to its parent registration statement, but the parent itself lives in its own filing form. Likewise, any post-effective amendments that the undertaking commits to are themselves separate filings and not bundled into the UNDER record.
Within the dataset, structural variability is concentrated on a few axes:
formType distinguishes initial undertakings (UNDER) from amendments (UNDER/A).entities[] is usually one but can be greater when multiple registrants share an undertaking.stateOfIncorporation and tickers may be absent or carry multiple values.*under.htm suffix is common but not guaranteed.Form UNDER filings have been accepted by EDGAR from June 2000 to the present. The form is a short ancillary submission and is consistently filed as an HTML document wrapped in the EDGAR SGML document envelope, alongside the standard EDGAR-generated full-submission text bundle. The dataset preserves this native presentation: the SGML header lines (<DOCUMENT>, <TYPE>, <SEQUENCE>, <FILENAME>, <DESCRIPTION>, <TEXT>) appear at the head of every document file, and the body is HTML. Form UNDER does not carry XBRL or iXBRL content, and linkToXbrl is always empty.
Several characteristics matter for downstream use:
fileNo field on each entity in metadata.json, which ties the undertaking to a specific 333- Securities Act registration statement. Joining UNDER records to the parent N-14 or S-6 filing on this key reconstructs the transactional context.description field on the filing — for example "Form UNDER - Undertaking to file reports, [Item 4 Form S-6]" — frequently names the SEC rule item the undertaking responds to and the parent form, giving a quick semantic classifier without parsing the HTML body.<!-- PAGEBREAK --> comment. Cover-letter content (counsel transmittal, acceleration request) precedes it; signature blocks close it.<TEXT> body. The closing </TEXT> and </DOCUMENT> lines must likewise be ignored or trimmed.formType and the accession number differ. Tracking the chain of UNDER and UNDER/A filings linked to the same fileNo reconstructs the amendment history of an undertaking.Form UNDER and Form UNDER/A are filed almost exclusively by registered investment companies under the Investment Company Act of 1940. Typical filers include:
The filer is the registrant on the underlying Securities Act registration statement. Where the registrant is an insurance company separate account, the depositor (the sponsoring insurance company) typically signs and transmits the undertaking on the registrant's behalf.
Operating companies, foreign private issuers, and other non-investment-company issuers do not file Form UNDER. Their deferral and post-effective commitments are handled inside the registration statement itself, through pre-effective amendments, or through Securities Act Rule 462. Form UNDER is therefore a 1940 Act registrant artifact, not a general Securities Act filing type.
A Form UNDER filing is created when a fund registrant has an active Securities Act registration statement in which one or more required items — financial statements, executed agreements, tax opinions, exhibits, or pricing supplements — cannot be supplied at the time of filing or effectiveness. Rather than delay the registration, the registrant submits a written undertaking committing to file those items later by post-effective amendment.
The filing is event-driven, not periodic. It appears only when a registration statement is in process and requires a deferred-materials commitment.
Common triggering contexts:
A Form UNDER/A is triggered when a prior undertaking needs to be revised, supplemented, or corrected — for example, when the scope of deferred documents changes, when the referenced registration file number is updated, or when the commitment is reworked during staff review. A new commitment for a different registration statement is a new UNDER, not an UNDER/A.
The undertaking mechanism sits inside the Securities Act of 1933 registration regime as applied to investment companies:
The undertaking is part of the registration package, not a standalone disclosure regime. Its function is procedural: it lets the Commission act on the registration statement on the understanding that the remaining items will follow through a defined path. EDGAR began accepting Form UNDER in 2000, and the dataset's earliest records are from June 2000. The form is intrinsically low-volume because it applies only to specific procedural situations.
Form UNDER sits in an unusual slot: a standalone procedural commitment filed by registered investment companies during the Securities Act registration process, with no substantive disclosure of its own. The most useful comparisons are to the parent registration statements that trigger it, the post-effective amendments that discharge it, the undertakings normally embedded inside registration statements, and a few adjacent EDGAR administrative submission types.
N-14 is the dominant parent filing behind Form UNDER. Registrants use N-14 to register securities issued in business combinations, reorganizations, and acquisitions, and routinely commit to supply final post-closing financials, tax opinions, or executed agreements by post-effective amendment. The two are content-wise opposite: N-14 carries the proxy/prospectus, financials, and fairness analysis; UNDER carries only the procedural promise to deliver specified missing items later. N-14 is long and narrative; UNDER is a short letter-form filing. For research on fund reorganizations, N-14 is the primary source and UNDER is a workflow signal that material items remain outstanding.
These cover open-end funds (N-1A), closed-end funds and BDCs (N-2), and unit investment trusts (S-6). Each generates undertakings, but typically embedded in Part C of the registration statement rather than filed as a freestanding UNDER. The Form UNDER dataset is therefore concentrated around N-14 activity and captures only the freestanding subset of investment-company undertakings; undertakings tied to routine N-1A, N-2, and S-6 effective registrations must be extracted from inside the parent filings.
These are the filings that fulfill an UNDER commitment. 485APOS/485BPOS are Rule 485 post-effective amendments used by open-end funds (485A requiring staff review, 485B immediately effective); 486APOS/486BPOS are the Rule 486 analogues for closed-end interval funds. The relationship is sequential: UNDER is the promise, the 485/486 amendment is the delivery. The substantive financials, opinions, and revised prospectus language live in the post-effective amendment, not in UNDER. Pairing an UNDER with the subsequent 485BPOS or 486BPOS is the natural way to confirm discharge.
Most registration statements (S-1, S-3, S-11, F-1, N-1A, N-2, and others) include standard undertakings in Part II (operating companies) or Part C (investment companies). These cover similar legal ground (commitments to file post-effective amendments, reflect material changes, deliver documents, address indemnification) but live inside the parent filing and are not separately indexable. Form UNDER is distinct because it isolates the undertaking as its own EDGAR submission with its own header, timestamp, and accession number. Studying undertaking language broadly requires parsing parent registration statements; studying the workflow of separately filed undertakings requires the Form UNDER dataset.
UNDER/A modifies, supplements, or corrects a prior UNDER, with the same structure and filer base. It typically appears when the scope of the original commitment changes or an error needs correction. Dataset users should link UNDER and UNDER/A by filer and filing window to reconstruct the final operative undertaking; counting each in isolation overstates the number of distinct commitments.
CORRESP carries filer-to-staff correspondence (typically responses to comment letters); UPLOAD carries staff-to-filer correspondence. They are procedural rather than substantive, which makes them superficially similar to UNDER. The distinction is directional and legal: CORRESP/UPLOAD document an interactive, discretionary review dialogue, while UNDER is a one-way formal commitment from registrant to Commission with legal force as part of the registration record.
Form UNDER is distinct on four axes:
N-14 supplies the substantive merger disclosure, 485BPOS/486BPOS supply the fulfillment, embedded Part C undertakings supply the broader undertaking universe, and CORRESP/UPLOAD supply the staff-registrant dialogue. None substitutes for Form UNDER when the question is specifically about freestanding undertaking submissions in the investment-company registration process.
The Form UNDER corpus is small and uniform, so the user base is specialist rather than broad. It serves fund regulatory and transactional counsel drafting undertakings, compliance teams closing them out, and a smaller set of researchers and corpus builders who value the dataset for its completeness on a rarely used procedural mechanism.
The primary users. In-house counsel at fund complexes and outside counsel with 1940 Act and Securities Act practices mine the dataset as a precedent library when drafting their own undertakings for N-14 reorganizations or fund-of-funds combinations. They extract the exact undertaking phrasing, the parent registration file number, the enumerated list of deferred documents (tax opinion, pro forma financials, final merger agreement, accountant consents), the cited rule item, and the cover-letter and signature conventions used by counsel or an authorized officer.
Deal counsel coordinating fund mergers and shell-fund combinations use Form UNDER records alongside the parent N-14. They focus on which exhibits prior registrants deferred, how the deferral was worded, and how the file-number cross-reference ties the commitment to the parent filing. The precedent informs decisions on which exhibits to defer and how to align the post-effective amendment timetable with closing.
Compliance officers and fund administrators use the records for follow-through tracking. Once a registrant commits to a future filing, they must ensure it lands. They pull the enumerated document list, any trigger dates in the undertaking text, and the linked parent file number, then reconcile each commitment against subsequent post-effective amendments to confirm closure.
Analysts studying EDGAR form usage and SEC staff review practice use the dataset to characterize when registrants file a standalone UNDER letter rather than embedding the undertaking inline. They rely on accession metadata (CIK, filing date, accession number) plus the unstructured letter body to produce filing-frequency timelines and issuer cohort views. The small count is itself the finding.
Law librarians and academic researchers in investment company law treat the corpus as a complete archival slice of a niche form. The full undertaking text, cited rule item, and named documents define the substantive legal commitment and support law-review work on N-14 procedure and Securities Act practice for funds.
Teams building retrieval systems over EDGAR use Form UNDER to extend coverage to obscure form types. The short, templated letters are a clean test set for entity extraction (file numbers, accession numbers, item references) and for full-form-type retrieval benchmarks.
The Form UNDER Files Dataset's value is precedent retrieval and registration-workflow reconciliation, not market analytics. The use cases below reflect that scope.
Drafting undertakings for N-14 fund reorganizations. Investment-company counsel pull the HTML body of prior UNDER filings to lift exact undertaking phrasing, the enumerated list of deferred items (tax opinion, pro forma financials, executed merger agreement, accountant consents), and the cited SEC rule item from the filing description. The precedent library is then used to draft a new freestanding undertaking for a pending N-14.
Reconciling deferred commitments against post-effective amendments. Fund compliance teams take the fileNo (333- parent registration number) from each entity block and join against subsequent 485BPOS, 486BPOS, or N-14/A filings on the same registration. The UNDER record supplies the list of promised documents and the date floor; the join confirms whether each promised item was actually delivered.
Reconstructing UNDER to UNDER/A amendment chains. Transactional counsel and archivists group records by fileNo and filer CIK, then order by filedAt to chain an initial UNDER to any later UNDER/A filings on the same registration. This produces the final operative undertaking for a reorganization and avoids double-counting superseded commitments.
Building an N-14 transaction map keyed on 333- file numbers. Researchers studying fund mergers extract entities[].fileNo, companyName, cik, and tickers from metadata.json to build a lookup linking each undertaking to its parent N-14 registration. The map is then used to pull the substantive merger prospectus and fairness disclosure from the related N-14 filing.
Benchmarking cover-letter and signature conventions. Outside counsel comparing drafting practice extract the cover transmittal letter (counsel letterhead, addressee, acceleration request) and the /s/ signature block from the page after the <!-- PAGEBREAK --> comment. The output is a style reference covering which firms appear as drafters, which officer titles sign (treasurer, secretary, fund counsel), and how acceleration is requested.
Entity-extraction test set for EDGAR RAG pipelines. LLM teams use the short, templated UNDER documents as a clean evaluation corpus for extracting 333- file numbers, accession numbers, cited rule items, and signatory names. The SGML-wrapped HTML structure also serves as a test case for parsers that must tolerate or strip the <DOCUMENT>, <TYPE>, <TEXT> header lines before processing the body.
Dataset Index JSON API: https://api.sec-api.io/datasets/form-under-files.json
This endpoint returns metadata describing the Form UNDER Files Dataset, including the dataset name, description, last update timestamp, earliest sample date, total record count, total dataset size, covered form types (UNDER and UNDER/A), container format (ZIP), and file types (TXT, JSON, HTML). It also returns the download URL for the entire dataset and a list of individual container files organized by year and month, each with its size, record count, last update timestamp, and download URL. Use this endpoint to monitor which containers have changed in the most recent refresh run, so you can selectively download only updated archives.
This endpoint does not require an API key.
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{
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"datasetId": "1f13365b-9ae0-6a43-89bf-077938f4b290",
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"datasetDownloadUrl": "https://api.sec-api.io/datasets/form-under-files.zip",
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"name": "Form UNDER Files Dataset",
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"description": "Form UNDER filings contain initial undertakings to file reports, submitted by registered investment companies in connection with Securities Act registration statements. These filings typically accompany registration statements on forms such as Form N-14 and represent a formal commitment by the registrant to file specified documents or information by post-effective amendment. The dataset includes all Form UNDER and Form UNDER/A filings submitted to EDGAR from June 2000 to present. Form UNDER/A filings represent amendments to previously submitted undertakings.",
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"earliestSampleDate": "2000-06-01",
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"totalRecords": 21,
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"totalSize": 41383,
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"formTypes": ["UNDER", "UNDER/A"],
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"containerFormat": "ZIP",
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"fileTypes": ["TXT", "JSON", "HTML"],
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"containers": [
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{
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"downloadUrl": "https://api.sec-api.io/datasets/form-under-files/2000/2000-06.zip",
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"key": "2000/2000-06.zip",
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"size": 4521,
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"records": 2,
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"updatedAt": "2026-05-13T01:24:11.000Z"
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}
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]
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}
Download Entire Dataset: https://api.sec-api.io/datasets/form-under-files.zip?token=YOUR_API_KEY
Downloads the complete dataset as a single ZIP archive containing all Form UNDER and UNDER/A filings from June 2000 to present. Because the dataset is compact, a full download is practical for one-off bulk access. This endpoint requires an API key passed via the token query parameter.
Download Single Container: https://api.sec-api.io/datasets/form-under-files/2000/2000-06.zip?token=YOUR_API_KEY
Downloads a single monthly container ZIP file instead of the entire dataset. Containers are organized by YYYY/YYYY-MM.zip, allowing targeted retrieval of filings from a specific month. Replace the year and month segment with any key value returned in the index JSON. This endpoint requires an API key passed via the token query parameter.
The dataset covers Form UNDER (initial undertaking) and Form UNDER/A (amendment to a previously filed undertaking). Both are short ancillary submissions filed by registered investment companies on EDGAR in connection with Securities Act of 1933 registration statements.
One record corresponds to a single Form UNDER or Form UNDER/A submission accepted by EDGAR, identified uniquely by its accession number. Each record is a folder containing a metadata.json file with the EDGAR submission header and one .htm file containing the SGML-wrapped HTML undertaking document (a cover transmittal letter followed by the operative undertaking page).
Form UNDER is filed almost exclusively by registered investment companies — open-end and closed-end management investment companies, unit investment trusts, business development companies, and insurance company separate accounts that register variable insurance products. Operating companies, foreign private issuers, and other non-investment-company issuers do not file Form UNDER; their deferral mechanisms are handled inside the registration statement or through Securities Act Rule 462.
A Form UNDER filing is event-driven, not periodic. It is created when a fund registrant has an active Securities Act registration statement (most commonly Form N-14 for fund reorganizations and business combinations) and one or more required items — tax opinions, executed agreements, pro forma financials, exhibits — cannot be supplied at effectiveness. The registrant submits the undertaking committing to file those items later by post-effective amendment.
Form UNDER is the procedural promise; post-effective amendments such as 485APOS, 485BPOS, 486APOS, and 486BPOS are the delivery. The substantive financials, opinions, and revised prospectus language live in the post-effective amendment, not in UNDER. Pairing an UNDER record with the subsequent 485BPOS or 486BPOS on the same 333- registration file number is the natural way to confirm that a commitment has been discharged.
The dataset includes all Form UNDER and Form UNDER/A filings submitted to EDGAR from June 2000 to the present. EDGAR began accepting Form UNDER in 2000, and the dataset's earliest records are from June 2000.
The dataset is distributed as monthly ZIP containers organized by YYYY/YYYY-MM.zip. Inside each container, filings are grouped under monthly partitions and each filing folder contains a metadata.json file and an .htm document wrapped in the EDGAR SGML document envelope. The dataset uses TXT, JSON, and HTML file types and does not include XBRL or iXBRL content.