ISO endorsement ยท interline (shared across commercial lines)

IL 09 21 Retrospective Premium Endorsement - Short Form

Filings
187
latest Oct 22, 2026
Filing companies
98
54 carrier groups
States
17
Latest edition
04 84
Apr 1984

Coverage description

An Insurance Services Office (ISO) standard form. It states that the policy premium will be determined by a separate retrospective premium endorsement, identified by policy number, that forms part of the policy.

Editions

Edition dates as filed, newest first. Filing counts include every state submission that lists the edition.

EditionFilingsCompaniesStatesFiled
04 84Apr 1984Latest1879817Nov 2021 to Oct 2026

What the filings show

  • Edition in use: in the past 12 months, 27 companies filed the 04 84 edition.
  • IL 09 23 (Retrospective Premium Endorsement - Exclusion of Retrospective Development Factors) is filed alongside it most often, in 187 of the same filings (100%).

Data from admitted P&C filings with state insurance departments, submitted Oct 2021 to Oct 2026, excluding withdrawn and rejected filings.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 IL 09 21, out of 54 in total.

CarrierFilingsStatesEditions, most filed firstLast filed
OLD Republic Group4 group companies filed it, led by BITCO General Insurance Corporation and BITCO National Insurance Company13104 84May 11, 2026
Markel Corporation Group4 group companies filed it, led by State National Insurance Company, Inc. and City National Insurance Company12504 84Oct 22, 2026
Tokio Marine Holdings Incorporated Group2 group companies filed it, led by Safety National Casualty Corporation and Philadelphia Indemnity Insurance Company12304 84Aug 27, 2026
Scor GroupGeneral Security National Insurance Company10104 84Jun 9, 2026
Sompo Group2 group companies filed it, led by Sompo America Insurance Company and Sompo America Fire and Marine Insurance Company10104 84Jun 18, 2026
Siriuspoint GroupSiriusPoint America Insurance Company9304 84Jun 15, 2026
Group 1001 Insurance Holdings GroupCLEAR SPRING PROPERTY AND CASUALTY COMPANY6204 84Mar 18, 2026
Nationwide Corporation Group7 group companies filed it, led by Allied Insurance Company of America and Nationwide Agribusiness Insurance Company6304 84Feb 12, 2025
WR Berkley Corporation Group2 group companies filed it, led by Intrepid Casualty Company and Berkley Casualty Company6204 84Apr 18, 2023
American International Group3 group companies filed it, led by Granite State Insurance Company and Illinois National Insurance Co.5204 84Sep 15, 2023

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States

Number of filings that include IL 09 21 in each state, Oct 2021 to Oct 2026. Darker states have more filings.

Tennessee: 0 filingsTNAlabama: 0 filingsALFlorida: 0 filingsFLGeorgia: 0 filingsGAOklahoma: 0 filingsOKSouth Carolina: 44 filingsSC44Arkansas: 0 filingsARMissouri: 1 filingMO1Indiana: 0 filingsINLouisiana: 0 filingsLAOhio: 2 filingsOH2Wisconsin: 1 filingWI1Texas: 5 filingsTX5Kentucky: 1 filingKY1Iowa: 0 filingsIAKansas: 0 filingsKSMississippi: 0 filingsMSNorth Carolina: 0 filingsNCNebraska: 0 filingsNESouth Dakota: 0 filingsSDMontana: 0 filingsMTNew Hampshire: 0 filingsNHVirginia: 0 filingsVAArizona: 0 filingsAZPennsylvania: 0 filingsPARhode Island: 1 filingRI1Michigan: 0 filingsMIAlaska: 0 filingsAKDistrict of Columbia: 0 filingsDCIdaho: 0 filingsIDMaryland: 1 filingMD1West Virginia: 0 filingsWVUtah: 0 filingsUTWyoming: 4 filingsWY4Delaware: 0 filingsDENew Mexico: 2 filingsNM2Colorado: 78 filingsCO78Connecticut: 0 filingsCTMaine: 0 filingsMENorth Dakota: 0 filingsNDIllinois: 5 filingsIL5Minnesota: 0 filingsMNNew Jersey: 0 filingsNJNew York: 0 filingsNYMassachusetts: 1 filingMA1Washington: 5 filingsWA5Oregon: 1 filingOR1Vermont: 0 filingsVTCalifornia: 34 filingsCA34Nevada: 1 filingNV1Hawaii: 0 filingsHI
FewerMore filingsNone

Often filed with

Standard-style form numbers that appear in the same filings most often.

  • IL 09 23Retrospective Premium Endorsement - Exclusion of Retrospective Development Factors187 filings
  • IL 09 11Supplement to Retrospective Premium Endorsement (Final Premium Computation)180 filings
  • IL 09 19Retrospective Premium Endorsement - Three Year Plan - Multiple Lines177 filings
  • IL 09 18Retrospective Premium Endorsement - One Year Plan - Multiple Lines175 filings
  • IL 09 20Retrospective Premium Endorsement - Long Term Construction Project - Multiple Lines174 filings
  • IL 00 21Nuclear Energy Liability Exclusion Endorsement (Broad Form)163 filings
  • IL 00 03Calculation of Premium158 filings
  • IL 00 17Common Policy Conditions151 filings
  • IL 12 01Policy Changes134 filings
  • IL 09 17Resident Agent Countersignature Endorsement124 filings

Recent filings

Latest filings that include this form number. Filed copies open in FilingFocus.

SubmittedCompanyStateEditionsTracking number
Oct 22, 2026State National Insurance Company, Inc.CO04 84STNA-135128706
Oct 6, 2026American Casualty Company of Reading, Pennsylvaniaand 5 moreCA04 84CNAB-135091690
Aug 28, 2026Jet Insurance CompanySC04 84MRTN-134878222
Aug 27, 2026Philadelphia Indemnity Insurance CompanyNM04 84PHLX-135063316
Jun 30, 2026Accredited Surety and Casualty Company, Inc.CO04 84ACSA-135005169
Jun 18, 2026Sompo America Fire and Marine Insurance Companyand 1 moreCO04 84SMPJ-134972831
Jun 18, 2026Sompo America Insurance CompanyCO04 84SMPJ-134985965
Jun 17, 2026Atlantic Specialty Insurance CompanyNM04 84BEAC-134983795
Jun 17, 2026Atlantic Specialty Insurance CompanySC04 84BEAC-134983796
Jun 17, 2026State Automobile Mutual Insurance CompanyCO04 84STAT-134983865
Jun 15, 2026SiriusPoint America Insurance CompanyCO04 84MRTN-134978899
Jun 15, 2026SiriusPoint America Insurance CompanyCO04 84MRTN-134978902

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All Interline and Common Policy Forms (ISO IL) forms

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