# SEC EDGAR Filing Generator Reference

Reference for identifying which software generated a given SEC 10-K HTML filing.
Built from direct inspection of EDGAR filings and market research (March 2026).

---

## 1. Major Vendors and HTML Signatures

### Workiva (Wdesk) -- Market Leader for 10-K/10-Q

**Filing agent CIK:** `0001628280`

**HTML comment signature (lines 1-3):**
```html
<?xml version='1.0' encoding='ASCII'?>
<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:{uuid},g:{uuid},d:{hex-id}-->
```

**Detection heuristics:**
- HTML comment: `XBRL Document Created with the Workiva Platform`
- HTML comment: `Copyright \d{4} Workiva`
- Third comment line contains `r:`, `g:`, `d:` UUIDs (document/generation tracking)
- `xml:lang="en-US"` attribute on `<html>` tag
- Body uses inline styles exclusively (no CSS classes on content elements)
- Heavy use of `<span>` with inline styles containing `background-color`, `font-family`, `font-size`, `font-weight`, `line-height` in every span
- Div IDs follow pattern: `i{hex32}_{number}` (e.g., `id="i56b78781f7c84a038f6ae0f6244f7dd8_1"`)
- Tables use `display:inline-table` and `vertical-align:text-bottom`
- iXBRL fact IDs follow pattern: `F_{uuid}` (e.g., `id="F_d8dc1eb1-109d-445d-a55a-3dde1a81ca63"`)
- No `<meta name="generator">` tag
- No CSS classes on body content (purely inline styles)

**Structural patterns:**
- Span-heavy: nearly every text fragment wrapped in `<span style="...">`
- Font specified as `font-family:'Times New Roman',sans-serif` (note: sans-serif fallback, unusual)
- Line-height specified on every span (e.g., `line-height:120%`)
- Background color explicitly set: `background-color:#ffffff`

**Known quality issues:**
- Extremely verbose HTML; simple paragraphs become deeply nested span trees
- Text extraction is clean because span boundaries align with word boundaries
- Large file sizes due to inline style repetition

---

### DFIN / Donnelley Financial Solutions (ActiveDisclosure)

DFIN operates under **two distinct CIKs** with **two different HTML output formats**.

#### DFIN "New" ActiveDisclosure (primary)

**Filing agent CIK:** `0000950170` (also `0000950130`)

**HTML comment signature:**
```html
<?xml version='1.0' encoding='ASCII'?>
<!-- DFIN New ActiveDisclosure (SM) Inline XBRL Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date :2025-02-18T12:36:24.4008+00:00 -->
<!-- Copyright (c) 2025 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
```

**Detection heuristics:**
- HTML comment: `DFIN New ActiveDisclosure`
- HTML comment: `http://www.dfinsolutions.com/`
- HTML comment: `Copyright (c) \d{4} Donnelley Financial Solutions`
- HTML comment: `Creation Date :` with ISO timestamp
- Body style: `padding:8px;margin:auto!important;`
- Inline styles use `font-kerning:none;min-width:fit-content;` on most spans
- Extensive use of `white-space:pre-wrap` on spans
- CSS class `item-list-element-wrapper` and `page-border-spacing` present
- iXBRL fact IDs follow pattern: `F_{uuid}`

**Structural patterns:**
- Every text span carries `min-width:fit-content` (distinctive)
- Uses `&#160;` for spacing extensively
- Uses `<p>` tags with inline margins for all paragraphs
- Tables use explicit `padding-top:0in;vertical-align:top;padding-bottom:0in` cell styles

#### DFIN Legacy (RR Donnelley heritage)

**Filing agent CIK:** `0001193125`

**HTML signature:**
```html
<?xml version='1.0' encoding='ASCII'?>
<html xmlns:link="..." xmlns:xbrldi="..." ...>
<head>
<title>10-K</title>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type"/>
</head>
<body style="line-height:normal;background-color:white;">
<h5 style="font-size:10pt;font-weight:bold"><a href="#toc">Table of Contents</a></h5>
```

**Detection heuristics:**
- No identifying HTML comments (no generator/copyright comment)
- Accession number prefix `0001193125` is definitive
- `<body style="line-height:normal;background-color:white;">`
- Immediately starts with `<h5>` Table of Contents link
- Uses deprecated namespace aliases: `xmlns:xl`, `xmlns:xbrll`, `xmlns:deprecated`
- iXBRL fact IDs follow pattern: `Fact_{large_number}` (e.g., `id="Fact_129727210"`)
- Uses `<FONT>` tags (HTML 3.2 style) in some documents
- Uppercase HTML tags in older filings (`<P>`, `<B>`, `<DIV>`)

**Structural patterns:**
- Cleaner HTML than ActiveDisclosure New
- Uses semantic `<h5>` for table of contents
- Inline styles are simpler and more standard
- File description filenames follow pattern: `d{number}d10k.htm`

---

### Toppan Merrill (Bridge)

**Filing agent CIKs:** `0001104659` (primary), `0001558370` (secondary)

**HTML comment signature:**
```html
<?xml version='1.0' encoding='ASCII'?>
<!-- iXBRL document created with: Toppan Merrill Bridge iXBRL 10.9.0.3 -->
<!-- Based on: iXBRL 1.1 -->
<!-- Created on: 2/21/2025 8:11:11 PM -->
<!-- iXBRL Library version: 1.0.9062.16423 -->
<!-- iXBRL Service Job ID: {uuid} -->
```

**Detection heuristics:**
- HTML comment: `iXBRL document created with: Toppan Merrill Bridge iXBRL`
- HTML comment: `iXBRL Library version:`
- HTML comment: `iXBRL Service Job ID:`
- Includes version number in comment (e.g., `10.9.0.3`)
- `<title>` tag contains company name + period end date (e.g., `Sunstone Hotel Investors,&#160;Inc._December 31, 2024`)
- Uses `xmlns:xs` alongside `xmlns:xsi` (both XML Schema namespaces)
- Body starts with `<div style="margin-top:30pt;"></div>` (distinctive)
- iXBRL hidden div uses `display:none;` (no additional styles on the div)

**Structural patterns:**
- Context IDs use descriptive names with GUIDs: `As_Of_12_31_2024_{base64-like}`, `From_01_01_2024_to_12_31_2024_{guid}`
- Hidden fact IDs follow pattern: `Hidden_{base64-like}`
- Unit ref IDs follow pattern: `Unit_Standard_USD_{base64-like}`
- No CSS classes used on content elements
- Relatively clean HTML structure

---

### RDG Filings (ThunderDome Portal)

**Filing agent CIK:** `0001437749`

**HTML signature:**
```html
<?xml version='1.0' encoding='ASCII'?>
<html xmlns:thunderdome="http://www.RDGFilings.com" ...>
 <head>
  <title>avpt20241231_10k.htm</title>
  <!-- Generated by ThunderDome Portal - 2/27/2025 6:06:48 PM -->
  <meta http-equiv="Content-Type" content="text/html"/>
 </head>
 <body style="cursor: auto; padding: 0in 0.1in; font-family: &quot;Times New Roman&quot;, Times, serif; font-size: 10pt;">
```

**Detection heuristics:**
- XML namespace: `xmlns:thunderdome="http://www.RDGFilings.com"`
- HTML comment: `Generated by ThunderDome Portal`
- `<title>` contains the filing filename
- Body style includes `cursor: auto; padding: 0in 0.1in`
- iXBRL fact IDs prefixed with `thunderdome-` (e.g., `id="thunderdome-EntityCentralIndexKey"`)
- Context ref IDs use simple date ranges: `d_2024-01-01_2024-12-31`
- Other fact IDs follow `ixv-{number}` or `c{number}` pattern

**Market presence:** ~14,000 filings/year, rank #9 among filing agents. About 5% of annual filings.

---

### Broadridge Financial Solutions (PROfile)

**Filing agent CIKs:** `0001140361` (primary), `0001133228` (secondary)

**HTML comment signature:**
```html
<!-- Licensed to: Broadridge
     Document created using Broadridge PROfile 25.1.1.5279
     Copyright 1995 - 2025 Broadridge -->
```

**Detection heuristics:**
- HTML comment: `Licensed to: Broadridge`
- HTML comment: `Document created using Broadridge PROfile` with version number
- HTML comment: `Copyright 1995 - \d{4} Broadridge`
- CSS classes with `BRPF` prefix: `BRPFPageBreak`, `BRPFPageBreakArea`, `BRPFPageFooter`, `BRPFPageHeader`, `BRPFPageNumberArea`
- CSS class: `DSPFListTable`
- CSS class: `cfttable`
- CSS class: `Apple-interchange-newline` (suggests Mac/WebKit origin)
- Context ref IDs use XBRL-standard descriptive format: `c20240101to20241231_AxisName_MemberName`

**Note:** Broadridge acquired CompSci Resources LLC in July 2024 and is integrating CompSci's Transform platform. Filings may transition to Broadridge branding over time.

---

### CompSci / Novaworks (Transform and GoFiler)

CompSci Resources produces two tools that leave distinct signatures.

#### CompSci Transform (now Broadridge)

**Filed via:** EdgarAgents LLC (`0001213900`) or other agents

**HTML comment signature:**
```html
<?xml version='1.0' encoding='ASCII'?>
<!-- Generated by CompSci Transform (tm) - http://www.compsciresources.com -->
<!-- Created: Mon Mar 17 19:46:10 UTC 2025 -->
```

**Detection heuristics:**
- HTML comment: `Generated by CompSci Transform`
- HTML comment: `http://www.compsciresources.com`
- XML namespace: `xmlns:compsci="http://compsciresources.com"`
- Body wrapped in: `<div style="font: 10pt Times New Roman, Times, Serif">`
- Uses `<!-- Field: Rule-Page -->` and `<!-- Field: /Rule-Page -->` HTML comments as structural markers
- Empty `<div>` tags used as spacers between paragraphs
- iXBRL context refs use simple sequential IDs: `c0`, `c1`, `c2`, ...
- iXBRL fact IDs follow `ixv-{number}` pattern
- Uses shorthand CSS: `font: 10pt Times New Roman, Times, Serif` (combined property)
- Margin shorthand: `margin: 0pt 0`

**Known quality issues:**
- Words can be broken across `<span>` tags mid-word
- Heavy use of `&#160;` for spacing
- Empty divs between every paragraph create parsing noise
- `<!-- Field: ... -->` comments interspersed throughout document body

#### Novaworks GoFiler (XDX format)

**Filed via:** SECUREX Filings (`0001214659`) or self-filed

**HTML signature:**
```html
<head>
     <title></title>
<meta http-equiv="Content-Type" content="text/html"/>
</head>
<!-- Field: Set; Name: xdx; ID: xdx_021_US%2DGAAP%2D2024%2D... -->
<!-- Field: Set; Name: xdx; ID: xdx_03B_... -->
```

**Detection heuristics:**
- HTML comments with pattern: `<!-- Field: Set; Name: xdx; ID: xdx_{code}_{data} -->`
- XDX comments appear between `</head>` and `<body>` (unusual placement)
- Body style: `font: 10pt Times New Roman, Times, Serif` (same shorthand as CompSci)
- Empty `<title></title>` tag
- iXBRL fact IDs use `xdx2ixbrl{number}` pattern (e.g., `id="xdx2ixbrl0102"`)
- Standard fact IDs use `Fact{number:06d}` pattern (e.g., `id="Fact000003"`)
- Context refs use `From{date}to{date}` or `AsOf{date}` format (no separators within date)

**XDX explained:** XDX (XBRL Data Exchange) is GoFiler's proprietary format that uses HTML tag ID attributes ("engrams") to embed XBRL metadata. The `xdx_` comments carry taxonomy, entity, period, and unit definitions that GoFiler uses to generate the final iXBRL.

---

### Discount EDGAR / NTDAS (XBRLMaster / EDGARMaster)

**Filing agent CIK:** `0001477932`

**HTML signature:**
```html
<head>
  <title>crona_10k.htm</title>
  <!--Document Created by XBRLMaster-->
  <meta http-equiv="Content-Type" content="text/html"/>
</head>
<body style="text-align:justify;font:10pt times new roman">
```

**Detection heuristics:**
- HTML comment: `Document Created by XBRLMaster`
- Body style: `text-align:justify;font:10pt times new roman`
- Hidden iXBRL div has `id="XBRLDIV"`
- Additional body styles include `margin-left:7%;margin-right:7%`
- Uses lowercase `times new roman` (no capitalization)
- iXBRL fact IDs use `ixv-{number}` pattern

---

### EdgarAgents LLC

**Filing agent CIK:** `0001213900`

EdgarAgents is a filing agent service, not a document creation tool. The HTML they submit is typically generated by CompSci Transform, GoFiler, or other tools. Check the HTML comments to identify the actual generator.

---

### DFIN Legacy (pre-iXBRL / SGML-era)

**Filing agent CIK:** `0001193125`

Older filings (pre-2019) from this CIK may appear in `<DOCUMENT>` SGML wrapper format:
```html
<DOCUMENT>
<TYPE>10-K
<SEQUENCE>1
<FILENAME>d913213d10k.htm
<DESCRIPTION>10-K
<TEXT>
<HTML><HEAD>
<TITLE>10-K</TITLE>
</HEAD>
<BODY BGCOLOR="WHITE" STYLE="line-height:Normal">
<Center><DIV STYLE="width:8.5in" align="left">
```

**Detection heuristics:**
- Uppercase HTML tags: `<HTML>`, `<HEAD>`, `<BODY>`, `<P>`, `<B>`
- `BGCOLOR="WHITE"` attribute (deprecated HTML)
- `<Center>` tag with capital C
- `<DIV STYLE="width:8.5in"` (page-width container)
- `<FONT>` tags for styling
- Filename pattern: `d{number}d10k.htm`

---

## 2. Filing Agent Market Share

Based on [secfilingdata.com](https://www.secfilingdata.com/top-filing-agents/) total filings across all form types:

| Rank | Filing Agent | CIK | 2025 Filings | Total (All Time) |
|------|-------------|-----|-------------|-----------------|
| 1 | Donnelley Financial (DFIN) | 0001193125 | 65,180 | 1,872,890 |
| 2 | EdgarAgents LLC | 0001213900 | 48,021 | 367,211 |
| 3 | Quality Edgar (QES) | 0001839882 | 38,017 | 151,031 |
| 4 | Toppan Merrill | 0001104659 | 48,260 | 988,715 |
| 5 | WallStreetDocs Ltd | 0001918704 | 22,387 | 56,431 |
| 6 | Workiva (Wdesk) | 0001628280 | 21,606 | 141,795 |
| 7 | M2 Compliance LLC | 0001493152 | 13,810 | 164,603 |
| 8 | Davis Polk & Wardwell LLP | 0000950103 | 16,231 | 326,359 |
| 9 | RDG Filings (ThunderDome) | 0001437749 | 14,209 | 187,270 |
| 10 | Morgan Stanley | 0001950047 | 12,822 | 56,468 |
| 11 | Broadridge | 0001140361 | -- | 597,664 |
| 14 | SECUREX Filings | 0001214659 | -- | 115,218 |
| 19 | Blueprint | 0001654954 | -- | 62,250 |
| 20 | FilePoint | 0001398344 | -- | 76,218 |
| 38 | Discount EDGAR | 0001477932 | -- | 37,422 |

**For 10-K/10-Q specifically (estimated from biotech IPO data and market research):**
- DFIN: ~40-50% of annual/quarterly filings
- Workiva: ~25-35% (has been gaining share from DFIN since ~2010)
- Toppan Merrill: ~10-15%
- RDG Filings: ~5%
- Broadridge/CompSci: ~5%
- Others (law firms, self-filed, smaller agents): ~5-10%

---

## 3. XBRL/iXBRL Tool Signatures

The iXBRL tagging tool is often the same as the filing generator, but not always. Key distinguishing patterns in the iXBRL layer:

| Tool | Context Ref Pattern | Fact ID Pattern | Unit Ref Pattern |
|------|-------------------|----------------|-----------------|
| Workiva | `C_{uuid}` | `F_{uuid}` | `U_{uuid}` |
| DFIN New | `C_{uuid}` | `F_{uuid}` | Standard names |
| DFIN Legacy | `Fact_{large_int}` | `Fact_{large_int}` | Standard names |
| Toppan Merrill | `As_Of_{date}_{guid}` / `From_{date}_to_{date}_{guid}` | `Hidden_{guid}` | `Unit_Standard_USD_{guid}` |
| ThunderDome | `d_{date_range}` / `i_{date}` | `thunderdome-{name}` or `ixv-{n}` or `c{n}` | Standard names |
| CompSci Transform | `c0`, `c1`, `c2` ... | `ixv-{number}` | Standard names |
| GoFiler (XDX) | `From{date}to{date}` / `AsOf{date}` | `xdx2ixbrl{number}` | Standard names |
| XBRLMaster | `From{date}to{date}` | `ixv-{number}` | Standard names |
| Broadridge PROfile | `c{date}to{date}_{axis}_{member}` | Descriptive | Standard names |

---

## 4. Detection Priority (Recommended Heuristic Order)

For maximum reliability, check signatures in this order:

1. **HTML comments** (first 10 lines) -- most generators embed identifying comments
   - `Workiva Platform` --> Workiva
   - `DFIN New ActiveDisclosure` --> DFIN New
   - `Toppan Merrill Bridge` --> Toppan Merrill
   - `ThunderDome Portal` --> RDG Filings
   - `CompSci Transform` --> CompSci/Broadridge
   - `Broadridge PROfile` --> Broadridge
   - `XBRLMaster` --> Discount EDGAR / NTDAS
2. **XML namespaces** on `<html>` tag
   - `xmlns:thunderdome="http://www.RDGFilings.com"` --> RDG
   - `xmlns:compsci="http://compsciresources.com"` --> CompSci
3. **XDX comments** between head and body --> GoFiler/Novaworks
4. **Accession number prefix** (first 10 digits) --> identifies filing agent CIK
5. **Body style patterns** as fallback
6. **iXBRL fact ID patterns** as secondary confirmation

---

## 5. Known Quality Issues by Generator

### CompSci Transform
- **Words broken across spans**: Text is split at arbitrary character boundaries, not word boundaries. A single word like "cybersecurity" may be split across 2-3 `<span>` tags. This breaks naive text extraction that operates per-element.
- **Empty div spacers**: `<div>\n\n</div>` between every paragraph adds noise.
- **Field comments in body**: `<!-- Field: Rule-Page -->` markers interspersed with content.

### Workiva
- **Extreme span nesting**: Every text run gets its own `<span>` with full inline style. A simple bold sentence may have 5+ spans.
- **Large file sizes**: Inline style repetition causes 10-K files to be 2-5x larger than equivalent DFIN filings.
- **Clean word boundaries**: Despite heavy span usage, spans align with word/phrase boundaries, making text extraction reliable.

### DFIN New ActiveDisclosure
- **`min-width:fit-content` everywhere**: Unusual CSS property on every span; may cause rendering inconsistencies in older browsers.
- **`font-kerning:none`**: Explicit kerning disable on all text spans.
- **Generally clean**: Text extraction works well; word boundaries respected.

### DFIN Legacy
- **Uppercase HTML tags**: Older filings use `<P>`, `<B>`, `<FONT>` -- need case-insensitive parsing.
- **Mixed HTML versions**: Some documents mix HTML 3.2 and 4.0 constructs.
- **SGML wrappers**: Some filings wrapped in `<DOCUMENT>` SGML envelope.

### GoFiler / Novaworks
- **XDX comment noise**: Multiple `<!-- Field: Set; ... -->` comments that must be stripped.
- **Generally clean HTML**: Body content is straightforward.

### Toppan Merrill Bridge
- **Clean output**: Among the cleanest generators. Minimal inline style bloat.
- **GUID-heavy IDs**: Context and unit refs use base64-like GUIDs that are less human-readable.

---

## 6. Self-Filed / In-House Filings

Some large filers submit directly using their own CIK as the accession number prefix. These filings have **no generator comment** and variable HTML quality.

**Detection:** Accession number prefix matches the filer's own CIK (e.g., Halliburton CIK `0000045012` files with accession `0000045012-25-000010`).

**However:** Even self-filed companies typically use a commercial tool. Halliburton's self-filed 10-K contains the Workiva comment signature, indicating they use Workiva but submit directly rather than through a filing agent.

**Truly in-house HTML** (no commercial tool) is rare among 10-K filers. When it occurs:
- No identifying comments
- No consistent structural patterns
- May use Word-to-HTML conversion (look for `mso-` CSS prefixes from Microsoft Office)
- May have minimal or no iXBRL tagging

---

## 7. Law Firm Filings

Several large law firms act as filing agents:
- Davis Polk & Wardwell (`0000950103`) -- 326K total filings
- Paul Weiss (`0000950142`) -- 56K total filings
- Foley & Lardner (`0000897069`) -- 30K total filings
- Sidley Austin (`0000905148`) -- 39K total filings
- Seward & Kissel (`0000919574`) -- 107K total filings

Law firms typically file transactional documents (S-1, proxy, 8-K) rather than periodic 10-K filings. The HTML in law-firm-filed documents often comes from Word conversion and lacks commercial generator signatures.

---

## 8. Summary: Quick Detection Regex Table

```
Pattern                                              | Generator
-----------------------------------------------------|------------------
/Workiva Platform/                                   | Workiva
/DFIN New ActiveDisclosure/                          | DFIN (New)
/Donnelley Financial Solutions/                      | DFIN (New)
/Toppan Merrill Bridge/                              | Toppan Merrill
/ThunderDome Portal/                                 | RDG Filings
/CompSci Transform/                                  | CompSci/Broadridge
/Broadridge PROfile/                                 | Broadridge
/XBRLMaster/                                         | Discount EDGAR
/xmlns:thunderdome="http:\/\/www\.RDGFilings\.com"/  | RDG Filings
/xmlns:compsci="http:\/\/compsciresources\.com"/     | CompSci
/Field: Set; Name: xdx/                             | GoFiler/Novaworks
/dfinsolutions\.com/                                 | DFIN
/min-width:fit-content/                              | DFIN (New)
/BRPFPage/                                           | Broadridge PROfile
/id="XBRLDIV"/                                       | XBRLMaster
```

---

## Sources

- Direct inspection of SEC EDGAR filings (March 2026)
- [secfilingdata.com/top-filing-agents](https://www.secfilingdata.com/top-filing-agents/) -- filing agent rankings
- [newstreetir.com -- Top SEC Filing Agents for Biotech IPOs](https://newstreetir.com/2025/05/14/who-are-the-top-sec-filing-agents-for-biotech-ipos/) -- biotech IPO market share
- [houseblend.io -- SEC Filing Software Platforms](https://www.houseblend.io/articles/sec-filing-software-platforms-pricing-compliance) -- vendor comparison
- [novaworkssoftware.com/inlinexbrl](https://www.novaworkssoftware.com/inlinexbrl.php) -- XDX format documentation
- [rdgfilings.com/thunderdome](https://rdgfilings.com/thunderdome-client-portal/) -- ThunderDome Portal
- [toppanmerrill.com/bridge](https://www.toppanmerrill.com/bridge/) -- Toppan Merrill Bridge
- [edgarmaster.com](https://edgarmaster.com/) -- EDGARMaster / XBRLMaster by NTDAS
- [pernasresearch.com -- DFIN analysis](https://pernasresearch.com/research-vault/donnelley-financial-initiation/) -- market share dynamics
