# EDGAR Filing Document

**Accession Number:** 0001496228
**File Stem:** 0000904454-26-000197
**Filing Date:** 2026-3
**Character Count:** 10967
**Document Hash:** 03a09f07f0882d0639d75f818bd5f0eb
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000904454-26-000197.hdr.sgml**: 20260323

**ACCESSION NUMBER**: 0000904454-26-000197

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260320

**FILED AS OF DATE**: 20260323

**DATE AS OF CHANGE**: 20260323

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** SRB CORP
- **CENTRAL INDEX KEY:** 0001496228

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-50070
- **FILM NUMBER:** 26783736

**BUSINESS ADDRESS:**
- **STREET 1:** 695 ATLANTIC AVENUE
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02111
- **BUSINESS PHONE:** 617-457-7527

**MAIL ADDRESS:**
- **STREET 1:** 695 ATLANTIC AVENUE
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02111

**FORMER NAME:**
- **FORMER CONFORMED NAME:** SRB Corp
- **DATE OF NAME CHANGE:** 20100709
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Plymouth Rock Co Inc
- **CENTRAL INDEX KEY:** 0001556246

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-50070
- **FILM NUMBER:** 26783735

**BUSINESS ADDRESS:**
- **STREET 1:** 695 ATLANTIC AVENUE
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02111
- **BUSINESS PHONE:** 617-951-1026

**MAIL ADDRESS:**
- **STREET 1:** 695 ATLANTIC AVENUE
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02111
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** SAFETY INSURANCE GROUP INC
- **CENTRAL INDEX KEY:** 0001172052
- **STANDARD INDUSTRIAL CLASSIFICATION:** FIRE, MARINE & CASUALTY INSURANCE [6331]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 134181699
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 20 CUSTOM HOUSE STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110
- **BUSINESS PHONE:** 617-951-0600

**MAIL ADDRESS:**
- **STREET 1:** 20 CUSTOM HOUSE STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** SAFETY HOLDINGS INC
- **DATE OF NAME CHANGE:** 20020424

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>SRB CORP<br><sub>(Last) (First) (Middle)</sub><br>695 ATLANTIC AVENUE<br><sub>(Street)</sub><br>BOSTON, MA 02111<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-20 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>SAFETY INSURANCE GROUP INC [ SAFT ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Plymouth Rock Co Inc<br><sub>(Last) (First) (Middle)</sub><br>695 ATLANTIC AVENUE<br><sub>(Street)</sub><br>BOSTON, MA 02111<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-20 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>SAFETY INSURANCE GROUP INC [ SAFT ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-03-20 |  | S |  | 14151 | D | $71.1220 | 1794655<sup>(1)(2)(3)(4)(5)</sup> | I | See<sup>(1)(2)(3)(4)(5)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) This Form 4 is being jointly filed by SRB Corporation, a Massachusetts corporation ("SRB"), and The Plymouth Rock Company Incorporated, a Massachusetts corporation ("PRC"), and each shall be deemed a Reporting Person. SRB is a direct, wholly-owned subsidiary of PRC and acts as investment manager to PRC and, in such capacity, may be deemed to have voting and dispositive power over the shares of Common Stock reported on this Form 4. SRB disclaims beneficial ownership of the shares of Common Stock reported on this Form 4, and this report shall not be deemed an admission that SRB is a beneficial owner of such shares for purposes of Section 16 or for any other purpose. (Continued in Footnote 2)

(2) The Reporting Persons are making this single joint filing because they may be deemed a "group" within the meaning of Section 13(d)(3) of the Securities Act of 1934, as amended. This joint filing shall not, however, be deemed an affirmation that a group exists among the Reporting Persons for the purposes of the Securities Exchange Act of 1934 or for any other purpose and each Reporting Person expressly disclaims beneficial ownership of any securities beneficially owned by any other person.

(3) PRC holds 4,120 of the shares of Common Stock reported on this Form 4. The following subsidiaries of PRC hold in the aggregate 772,856 shares of the Common Stock reported on this Form 4: Plymouth Rock Security Corporation, a Massachusetts security corporation ("PRSC"); Plymouth Rock Assurance Corporation, a Massachusetts corporation ("PRAC"); Plymouth Rock Assurance Preferred Corporation, a New York corporation ("PRAPC"); Plymouth Rock Assurance Corporation of New York, a New York corporation ("PRACNY"); Pilgrim Insurance Company, a Massachusetts corporation ("Pilgrim"); Plymouth Rock Home Assurance Corporation, a Massachusetts corporation ("PRHAC"); Bunker Hill Insurance Casualty Company, a Massachusetts corporation ("BHICC"); Bunker Hill Preferred Insurance Company, a Massachusetts corporation ("BHPREFIC"); Bunker Hill Property Insurance Company, a Massachusetts corporation ("BHPIC"); (Continued in Footnote 4)

(4) and Bunker Hill Insurance Company, a Massachusetts corporation ("BHIC"). PRSC, PRAC, and PRHAC are direct wholly-owned subsidiaries of PRC. PRAPC and PRACNY are direct wholly-owned subsidiaries of PRAC. Pilgrim is a direct wholly-owned subsidiary of SRB. BHICC, BHPREFIC, BHPIC, and BHIC are direct wholly-owned subsidiaries of PRHAC. Palisades Safety and Insurance Association, a New Jersey reciprocal insurance exchange ("PSIA"), is managed by a subsidiary of PRC. PSIA and the following subsidiaries of PSIA hold in the aggregate 1,017,679 shares of the Common Stock reported on this Form 4: High Point Safety and Insurance Company, a New Jersey corporation ("HPSIC"); High Point Property and Casualty Insurance Company, a New Jersey corporation ("HPPCIC"); High Point Preferred Insurance Company, a New Jersey corporation ("HPPIC"); Palisades Insurance Company, a New Jersey corporation ("PICNJ"); (Continued in Footnote 5)

(5) Twin Lights Insurance Company, a New Jersey corporation ("TLIC"); and Teachers Auto Insurance Company of New Jersey, a New Jersey corporation ("TAIC"). HPSIC, HPPIC, TLIC, and TAIC are direct wholly-owned subsidiaries of HPPCIC, which is a direct wholly-owned subsidiary of PSIA, as is PICNJ. PRC disclaims beneficial ownership of the shares of Common Stock reported on this Form 4 except to the extent of its pecuniary interest therein, and this report shall not be deemed an admission that PRC is a beneficial owner of such shares for purposes of Section 16 or for any other purpose.

**Signature:** /s/ Frederick C. Childs  
**Date:** 2026-03-23

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**