Coverage description
A National Council on Compensation Insurance (NCCI) standard form. It sets how the premium is calculated when you choose a three-year retrospective rating plan, combining this policy, any scheduled policies and their renewals into one adjustment based on losses over the three years.
Updated
What the form says
Key clauses from edition D, the latest revision, quoted as filed.
“The rating plan period is the three-year period beginning with the effective date of this endorsement.”
WC 00 05 04 D
What period is rated together. Premium and losses for this policy, the policies listed in the Schedule and the renewals of each are combined over three years and adjusted as one plan, not year by year.
“Retrospective rating plan premium is the sum of basic premium, converted losses, plus the excess loss premium”
WC 00 05 04 D
What the premium is made of. Basic premium (standard premium times the basic premium factor) plus incurred losses times the loss conversion factor, plus any excess loss or development charge, is multiplied by the tax multiplier and held between the minimum and maximum set by the Schedule factors. Over the three years, tax multipliers and excess loss premium factors may change by endorsement.
“We may make interim calculations of retrospective rating plan premium for the first year and the first two years of the rating plan period.”
WC 00 05 04 D
When the premium is calculated. The regular calculation uses losses valued six months after the three years end and is repeated annually. The insurer may also run interim calculations on losses valued six months after the first year and after the first two years.
“This short rate premium will be the minimum retrospective rating plan premium”
WC 00 05 04 D
What happens if you end the plan early. If you cancel or do not renew, standard premium is raised by the short rate table and becomes the minimum, while the maximum is based on standard premium extended pro rata to three years (1,095 days). The short rate step does not apply if the work is completed, the business is sold or you retire from it.
How the form has changed
3 changes across 2 revisions, newest first. Each edition is compared with the one before it, using wording from filed copies.
Edition D
Compared with edition CLatest editionRenames the third component of the basic premium factor from insurance charge to net aggregate loss factor. The formula and the other provisions are unchanged.
Edition C
“Insurance charge”
Edition D
“Net aggregate loss factor”
Edition C
Compared with edition BLosses reported as fully fraudulent or as noncompensable are added to the losses left out of the rating formula.
Edition B
Not in this edition
Edition C
“Reported as fully fraudulent”
The passenger seat surcharge under Classification Code 7421 is no longer listed among the premium and losses left out of the plan.
Edition B
“Premium developed by the passenger seat surcharge under Classification Code 7421”
Edition C
Removed
Editions
Revision letters as filed, newest first. Filing counts include every state submission that lists the edition.
| Edition | Filings | Companies | States | Filed | Document |
|---|---|---|---|---|---|
| DLatest | 64 | 40 | 9 | Jan 2022 to Sep 2026 | View PDF |
| C | 28 | 31 | 5 | May 2022 to Jul 2026 | View PDF |
| B | 6 | 6 | 2 | Mar 2022 to Jun 2026 | View PDF |
1 other edition date appears in one or two filings each, often carrier-specific versions: Original.
What the filings show
- Edition in use: in the past 12 months, 17 companies filed edition D and 13 companies filed edition C.
- WC 00 05 03 (Retrospective Rating Plan Premium Endorsement One-Year Plan) is filed alongside it most often, in 96 of the same filings (99%).
Filed under
Data from admitted P&C filings with state insurance departments, submitted Nov 2021 to Sep 2026, excluding withdrawn and rejected filings. One filing can cover several affiliated companies.
Carriers filing this form
The 10 carrier groups with the most filings that include WC 00 05 04, out of 23 in total.
| Carrier | Filings | States | Editions, most filed first | Last filed |
|---|---|---|---|---|
| Brookfield Wealth Solutions Group4 group companies filed it, led by Argonaut Insurance Company and Argonaut-Midwest Insurance Company | 19 | 1 | D | Jun 4, 2026 |
| Nationwide Corporation Group3 group companies filed it, led by Crestbrook Insurance Company and National Casualty Company | 10 | 1 | CD | Jun 30, 2026 |
| AXA Insurance Group5 group companies filed it, led by Greenwich Insurance Company and XL Insurance America, Inc. | 7 | 3 | BCD | Jun 25, 2026 |
| Acuity, A Mutual Insurance Company | 6 | 2 | CD | Jul 1, 2026 |
| Sompo Group2 group companies filed it, led by Sompo America Fire and Marine Insurance Company and Sompo America Insurance Company | 6 | 2 | D | Jun 15, 2026 |
| Tokio Marine Holdings Incorporated Group2 group companies filed it, led by Safety First Insurance Company and Safety National Casualty Corporation | 6 | 2 | D | May 14, 2025 |
| RLI Insurance GroupRLI Insurance Company | 5 | 1 | D | Aug 18, 2026 |
| THE Hanover Insurance Group6 group companies filed it, led by Allmerica Financial Alliance Insurance Company and Allmerica Financial Benefit Insurance Company | 5 | 1 | C | Jun 23, 2026 |
| Arch Insurance Group2 group companies filed it, led by Arch Indemnity Insurance Company and Arch Insurance Company | 4 | 1 | D | Apr 8, 2026 |
| Louisiana Workers Compensation GroupPrescient National Insurance Company | 4 | 1 | D | Jul 2, 2025 |
States
Number of filings that include WC 00 05 04 in each state, Nov 2021 to Sep 2026. Darker states have more filings.
Often filed with
Standard-style form numbers that appear in the same filings most often.
- WC 00 05 03Retrospective Rating Plan Premium Endorsement One-Year Plan96 filings
- WC 00 05 05Retrospective Rating Plan Premium Endorsement Wrap-Up Construction Project95 filings
- WC 00 04 19Premium Due Date Endorsement92 filings
- WC 00 04 22Terrorism Risk Insurance Program Reauthorization Act Disclosure Endorsement91 filings
- WC 00 05 10Retrospective Rating Plan Premium Endorsement Non-Ratable Catastrophe Element or Surcharge91 filings
- WC 00 01 06Longshoremen's and Harbor Workers' Compensation Act Coverage Endorsement90 filings
- WC 00 01 11Migrant and Seasonal Agricultural Worker Protection Act Coverage90 filings
- WC 00 03 04Insurance Company as Insured Endorsement90 filings
- WC 00 03 05Joint Venture as Insured Endorsement90 filings
- WC 00 03 15Domestic and Agricultural Workers Exclusion Endorsement90 filings
Recent filings
Latest filings that include this form number. Filed copies open in FilingFocus.
| Submitted | Company | State | Editions | Tracking number |
|---|---|---|---|---|
| Sep 16, 2026 | ZNAT Insurance Company | CT | D | ZICO-135090521 |
| Aug 18, 2026 | RLI Insurance Company | CO | D | RLSC-135057018 |
| Jul 1, 2026 | Acuity, A Mutual Insurance Company | CO | C | ACUT-134982793 |
| Jun 30, 2026 | American Casualty Company of Reading, Pennsylvaniaand 5 more | CO | D | CNAB-135003197 |
| Jun 30, 2026 | Crestbrook Insurance Companyand 1 more | CO | C | NWPP-135003409 |
| Jun 30, 2026 | National Casualty Company | CO | D | NWPP-135004216 |
| Jun 25, 2026 | AXA XL Insurance Company Americas | PA | C | XLAM-135000406 |
| Jun 23, 2026 | Allmerica Financial Alliance Insurance Companyand 5 more | CO | C | HNVX-134968029 |
| Jun 23, 2026 | AXA XL Insurance Company Americasand 3 more | CO | B | XLAM-134996276 |
| Jun 15, 2026 | Sompo America Fire and Marine Insurance Companyand 1 more | CO | D | SMPJ-134970923 |
| Jun 4, 2026 | Argonaut-Midwest Insurance Company | CO | D | ARGN-134974739 |
| Jun 4, 2026 | Argonaut Insurance Company | CO | D | ARGN-134974742 |
Most filed NCCI WC forms
- WC 00 00 01 Information Page
- WC 00 04 19 Part Five, Premium Amendatory Endorsement
- WC 00 00 00 Workers Compensation and Employers Liability Insurance Policy
- WC 00 04 21 Catastrophe (Other Than Certified Acts of Terrorism) Premium Endorsement
- WC 00 04 06 Premium Discount Endorsement
- WC 00 03 13 Waiver of Our Right to Recover From Others Endorsement
- WC 00 04 22 Terrorism Risk Insurance Program Reauthorization Act Disclosure Endorsement
- WC 00 03 08 Partners, Officers and Others Exclusion Endorsement
- WC 00 03 03 Employers Liability Coverage Endorsement
- WC 00 03 11 Voluntary Compensation and Employers Liability Coverage Endorsement
- WC 00 04 03 Experience Rating Modification Factor Endorsement
- WC 00 04 04 Pending Rate Change Endorsement