# EDGAR Filing Document

**Accession Number:** 0001400240
**File Stem:** 0000899243-23-006241
**Filing Date:** 2023-2
**Character Count:** 15222
**Document Hash:** e5c1cb1d999101a38dfa45c584cb2bfb
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000899243-23-006241.hdr.sgml**: 20230227

**ACCESSION NUMBER**: 0000899243-23-006241

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20230227

**FILED AS OF DATE**: 20230227

**DATE AS OF CHANGE**: 20230227

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** AFEYAN NOUBAR
- **CENTRAL INDEX KEY:** 0001222012

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40657
- **FILM NUMBER:** 23676682

**MAIL ADDRESS:**
- **STREET 1:** C/O FLAGSHIP PIONEERING, INC.
- **STREET 2:** 55 CAMBRIDGE PARKWAY, SUITE 800E
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Flagship Pioneering Inc.
- **CENTRAL INDEX KEY:** 0001400240
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40657
- **FILM NUMBER:** 23676685

**BUSINESS ADDRESS:**
- **STREET 1:** 55 CAMBRIDGE PARKWAY, SUITE 800E
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
- **BUSINESS PHONE:** 617 868-1888

**MAIL ADDRESS:**
- **STREET 1:** 55 CAMBRIDGE PARKWAY, SUITE 800E
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142

**FORMER NAME:**
- **FORMER CONFORMED NAME:** Flagship Ventures Management, Inc.
- **DATE OF NAME CHANGE:** 20070522
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Flagship Pioneering Special Opportunities Fund II, L.P.
- **CENTRAL INDEX KEY:** 0001761283
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40657
- **FILM NUMBER:** 23676683

**BUSINESS ADDRESS:**
- **STREET 1:** 55 CAMBRIDGE PARKWAY
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
- **BUSINESS PHONE:** 617-868-1888

**MAIL ADDRESS:**
- **STREET 1:** 55 CAMBRIDGE PARKWAY
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Flagship Pioneering Special Opportunities Fund II General Partner LLC
- **CENTRAL INDEX KEY:** 0001826217
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40657
- **FILM NUMBER:** 23676684

**BUSINESS ADDRESS:**
- **STREET 1:** 55 CAMBRIDGE PARKWAY
- **STREET 2:** 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
- **BUSINESS PHONE:** 617-868-1888

**MAIL ADDRESS:**
- **STREET 1:** 55 CAMBRIDGE PARKWAY
- **STREET 2:** 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Omega Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001850838
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **IRS NUMBER:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 20 ACORN PARK DRIVE
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02140
- **BUSINESS PHONE:** (617) 949-4360

**MAIL ADDRESS:**
- **STREET 1:** 20 ACORN PARK DRIVE
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02140

### 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>Flagship Pioneering Inc.<br><sub>(Last) (First) (Middle)</sub><br>55 CAMBRIDGE PARKWAY, SUITE 800E<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02142<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-02-27 | **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>Omega Therapeutics, Inc. [ OMGA ] | **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>Flagship Pioneering Special Opportunities Fund II General Partner LLC<br><sub>(Last) (First) (Middle)</sub><br>55 CAMBRIDGE PARKWAY, SUITE 800E<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02142<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-02-27 | **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>Omega Therapeutics, Inc. [ OMGA ] | **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>Flagship Pioneering Special Opportunities Fund II, L.P.<br><sub>(Last) (First) (Middle)</sub><br>55 CAMBRIDGE PARKWAY, SUITE 800E<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02142<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-02-27 | **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>Omega Therapeutics, Inc. [ OMGA ] | **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>AFEYAN NOUBAR<br><sub>(Last) (First) (Middle)</sub><br>55 CAMBRIDGE PARKWAY, SUITE 800E<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02142<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-02-27 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Omega Therapeutics, Inc. [ OMGA ] | **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 | 2023-02-27 |  | P<sup>(1)</sup> |  | 1993986 | A | $5.78 | 7508693 | I | By Flagship Pioneering Special Opportunities Fund II, L.P.<sup>(2)</sup> |
| Common Stock | 2023-02-27 |  | P<sup>(1)</sup> |  | 1329324 | A | $5.78 | 1329324 | I | By Flagship Pioneering Fund VII, L.P.<sup>(3)</sup> |
| Common Stock |  |  |  |  |  |  |  | 1088470 | I | By Flagship V VentureLabs Rx Fund, L.P.<sup>(4)</sup> |
| Common Stock |  |  |  |  |  |  |  | 5896386 | I | By Flagship Ventures Fund V, L.P.<sup>(5)</sup> |
| Common Stock |  |  |  |  |  |  |  | 8617413 | I | By Flagship Pioneering Fund VI, L.P.<sup>(6)</sup> |
| Common Stock |  |  |  |  |  |  |  | 970588 | I | By Nutritional Health LTP Fund, L.P.<sup>(7)</sup> |
| Common Stock |  |  |  |  |  |  |  | 1617646 | I | By FPN, L.P.<sup>(8)</sup> |
| Common Stock |  |  |  |  |  |  |  | 2197059 | I | By Flagship VentureLabs V, LLC<sup>(9)</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) On February 27, 2023, Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II") and Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") purchased 1,993,986 shares and 1,329,324 shares, respectively, of the Issuer's Common Stock in a registered direct offering at a price of $5.78 per share pursuant to a Securities Purchase Agreement dated February 22, 2023.

(2) Represents shares held directly by Flagship Opportunities Fund II. Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Flagship Opportunities Fund II GP. Noubar B. Afeyan, Ph.D. is the Chief Executive Officer, sole shareholder and director of Flagship Pioneering. Each of the reporting persons except Flagship Opportunities Fund II disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(3) Represents shares held directly by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(4) Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V Rx. Dr. Afeyan is the sole manager of Flagship V GP. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(5) Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship V GP is the general partner of Flagship Fund V. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(6) Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering is the manager of Flagship Fund VI GP. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(7) Represents shares held directly by Nutritional Health LTP Fund, L.P. ("Nutritional LTP"). Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Flagship Pioneering is the manager of Nutritional LTP GP. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(8) Represents shares held directly by FPN, L.P. ("FPN Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN Fund. Flagship Pioneering is the manager of FPN GP. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

(9) Represents shares held directly by Flagship VentureLabs V, LLC ("VentureLabs V"). VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

**Signature:** Flagship Pioneering, Inc., By: /s/ Noubar B. Afeyan, Ph.D., Chief Executive Officer  
**Date:** 2023-02-27

**Signature:** Flagship Pioneering Special Opportunities Fund II General Partner LLC, By: Flagship Pioneering, Inc. its manager, By: /s/ Noubar B. Afeyan Ph.D., Chief Executive Officer  
**Date:** 2023-02-27

**Signature:** Flagship Pioneering Special Opportunities Fund II, L.P., By: Flagship Pioneering Special Opportunities Fund II General Partner LLC, its general partner, By: Flagship Pioneering, Inc. its manager, By: /s/ Noubar B. Afeyan Ph.D., Chief Executive Officer  
**Date:** 2023-02-27

**Signature:** /s/ Noubar B. Afeyan, Ph.D.  
**Date:** 2023-02-27

### 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.**