Coverage description
A National Council on Compensation Insurance (NCCI) standard form. It sets the premium for this policy and the other policies listed with it, which can include general liability and auto, by a retrospective rating plan that runs one year and recalculates premium from incurred losses between a minimum and a maximum.
Updated
What the form says
Key clauses from edition D, the latest revision, quoted as filed.
“The rating plan period is the one-year period beginning with the effective date of this endorsement.”
WC 00 05 12 D
How long the plan runs. Premium is rated on the losses of a single year starting on the endorsement's effective date. If this policy is cancelled, the cancellation date ends the rating period early.
“Insurance policies listed in the Schedule will be combined with this policy to calculate the retrospective rating plan premium.”
WC 00 05 12 D
Which policies are rated together. The schedule lists the policies whose premium is combined, so workers compensation, general liability and auto policies can share one retrospective premium. Loss limitations and excess loss premium factors are set by line of insurance in the schedule.
“The retrospective rating plan premium will not be less than the minimum or more than the maximum retrospective rating plan premium.”
WC 00 05 12 D
What bounds the final premium. Minimum and maximum premium factors in the schedule are applied to standard premium, so the premium worked out from losses always lands between those two amounts.
“as of a date six months after the rating plan period ends and annually thereafter”
WC 00 05 12 D
When the premium is recalculated. The first calculation uses losses valued six months after the year ends and is repeated each year after that. After each one you pay the amount due or receive a refund, until you and the insurer agree a calculation is final.
How the form has changed
1 change across 1 revision, newest first. Each edition is compared with the one before it, using wording from filed copies.
Edition D
Compared with edition CLatest editionLists a net aggregate loss factor, in place of an insurance charge, among the costs the basic premium factor includes, alongside general administration and loss control costs.
Edition C
“Insurance charge”
Edition D
“Net aggregate loss factor”
Editions
Revision letters as filed, newest first. Filing counts include every state submission that lists the edition.
What the filings show
- Edition in use: in the past 12 months, 15 companies filed edition D and 9 companies filed edition C.
- WC 00 05 03 (Retrospective Rating Plan Premium Endorsement One-Year Plan) is filed alongside it most often, in 75 of the same filings (99%).
Filed under
Data from admitted P&C filings with state insurance departments, submitted Nov 2021 to Aug 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 12, out of 20 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 |
| AXA Insurance Group5 group companies filed it, led by Greenwich Insurance Company and XL Insurance America, Inc. | 6 | 2 | BD | Jun 23, 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 |
| 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 |
| Tokio Marine Holdings Incorporated Group2 group companies filed it, led by Safety First Insurance Company and Safety National Casualty Corporation | 4 | 1 | D | May 14, 2025 |
| American Financial Group4 group companies filed it, led by Great American Alliance Insurance Company and Great American Assurance Company | 3 | 1 | C | Jun 11, 2024 |
| Liberty Mutual Group6 group companies filed it, led by Employers Insurance Company of Wausau and LM Insurance Corporation | 3 | 3 | D | Mar 21, 2022 |
States
Number of filings that include WC 00 05 12 in each state, Nov 2021 to Aug 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 Plan75 filings
- WC 00 05 04Retrospective Rating Plan Premium Endorsement Three-Year Plan75 filings
- WC 00 05 05Retrospective Rating Plan Premium Endorsement Wrap-Up Construction Project75 filings
- WC 00 05 14Retrospective Rating Plan Premium Endorsement Wrap- Up Constructionproje Ct—multiple Lines74 filings
- WC 00 05 13Retrospective Rating Plan Premium Endorsement Three- Year Plan—multiplelines73 filings
- WC 00 05 11Retrospective Premium Endorsement-- Short Form72 filings
- WC 00 05 15Retrospective Rating Plan Premium Endorsement-- Flexibility Options72 filings
- WC 00 01 02Federal Mine Safety and Health Act Coverage Endorsement71 filings
- WC 00 01 04Federal Employers' Liability Act Coverage Endorsement71 filings
- WC 00 01 06Longshoremen's and Harbor Workers' Compensation Act Coverage Endorsement71 filings
Recent filings
Latest filings that include this form number. Filed copies open in FilingFocus.
| Submitted | Company | State | Editions | Tracking number |
|---|---|---|---|---|
| Aug 18, 2026 | RLI Insurance Company | CO | D | RLSC-135057018 |
| Jun 30, 2026 | American Casualty Company of Reading, Pennsylvaniaand 5 more | CO | D | CNAB-135003197 |
| 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 |
| Jun 4, 2026 | Rockwood Casualty Insurance Company | CO | D | ARGN-134974764 |
| Apr 8, 2026 | Arch Insurance Company | CO | D | AICO-G134902631 |
| Apr 8, 2026 | Arch Indemnity Insurance Company | CO | D | AICO-G134902710 |
| Jan 8, 2026 | The Cincinnati Casualty Companyand 2 more | NY | C | CNNA-134764673 |
| Dec 3, 2025 | AXA XL Insurance Company Americas | KY | D | XLAM-134756293 |
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