# EDGAR Filing Document

**Accession Number:** 0001935814
**File Stem:** 0000899243-23-000452
**Filing Date:** 2023-1
**Character Count:** 8718
**Document Hash:** 749d730f513088b3f23408a8edd2ef9f
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000899243-23-000452.hdr.sgml**: 20230103

**ACCESSION NUMBER**: 0000899243-23-000452

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20221229

**FILED AS OF DATE**: 20230103

**DATE AS OF CHANGE**: 20230103

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Opportunity Fund II, L.P.
- **CENTRAL INDEX KEY:** 0001885327
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504173

**BUSINESS ADDRESS:**
- **STREET 1:** 300 TECHNOLOGY SQUARE
- **STREET 2:** 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 300 TECHNOLOGY SQUARE
- **STREET 2:** 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Associates Opportunity II, LP
- **CENTRAL INDEX KEY:** 0001935814
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504172

**BUSINESS ADDRESS:**
- **STREET 1:** 300 TECHNOLOGY SQUARE, 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 1 857 201 2700

**MAIL ADDRESS:**
- **STREET 1:** 300 TECHNOLOGY SQUARE, 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Associates Opportunity II, LLC
- **CENTRAL INDEX KEY:** 0001935810
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39438
- **FILM NUMBER:** 23504171

**BUSINESS ADDRESS:**
- **STREET 1:** 300 TECHNOLOGY SQUARE, 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857 201 2700

**MAIL ADDRESS:**
- **STREET 1:** 300 TECHNOLOGY SQUARE, 8TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Disc Medicine, Inc.
- **CENTRAL INDEX KEY:** 0001816736
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 851613057
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 300 ONE KENDALL SQUARE, 3RD FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** (617) 401-4400

**MAIL ADDRESS:**
- **STREET 1:** 300 ONE KENDALL SQUARE, 3RD FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Gemini Therapeutics, Inc. /DE
- **DATE OF NAME CHANGE:** 20210209

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FS Development Corp.
- **DATE OF NAME CHANGE:** 20200702

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

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Atlas Venture Opportunity Fund II, L.P.<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2022-12-29 | **4. 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>_ _ | **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>Atlas Venture Associates Opportunity II, LP<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2022-12-29 | **4. 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>_ _ | **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>Atlas Venture Associates Opportunity II, LLC<br><sub>(Last) (First) (Middle)</sub><br>300 TECHNOLOGY SQUARE, 8TH FLOOR<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02139<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>Disc Medicine, Inc. [ IRON ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2022-12-29 | **4. 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>_ _ | **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 Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Common Stock | 218326 | D<sup>(1)</sup> |  |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) These shares are held directly by Atlas Venture Opportunity Fund II, L.P. ("Atlas Opportunity II"). Atlas Venture Associates Opportunity II, L.P. ("Associates II") is the general partner of Atlas Opportunity II. Atlas Venture Associates Opportunity II, LLC ("Associates II LLC") is the general partner of Associates II. Each of Associates II and Associates II LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Opportunity II, except to the extent of its pecuniary interest therein, if any.

**Signature:** Atlas Venture Opportunity Fund II, L.P., By: Atlas Venture Associates Opportunity II, L.P., its general partner, By: Atlas Venture Associates Opportunity II, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Associates Opportunity II, L.P., By: Atlas Venture Associates Opportunity II, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

**Signature:** Atlas Venture Associates Opportunity II, LLC By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan  
**Date:** 2023-01-03

### 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.**