Flagship V VentureLabs Rx Fund, L.P. - 03 Feb 2025 SCHEDULE 13D/A Report for OMEGA THERAPEUTICS, INC. Common Stock, $0.001 par value per share (OMGAQ)

Filing manager
Flagship V VentureLabs Rx Fund, L.P.
Reporting owner
Noubar Afeyan
Security
OMEGA THERAPEUTICS, INC. Common Stock, $0.001 par value per share
Beneficially owned shares
29,225,579 shares
Ownership signal CIK-linked ownership evidence from parsed SEC filings. 2 signals
Large-stake signal

Form

SCHEDULE 13D/A

Active or control-oriented beneficial ownership filing.

Ownership

53%

Beneficial ownership of this reported class.

Shares

29,225,579 shares

Shares beneficially owned as disclosed.

Event date

03 Feb 2025

Date tied to the ownership event or amendment.

Accepted by SEC

05 Feb 2025

EDGAR acceptance date.

How to read this large-stake filing
  • Schedule 13D/G filings focus on beneficial ownership stakes, not a full portfolio.
  • Compare this filing with the holder history and issuer page before treating the percentage as a current position.
  • Use amendments to understand whether the disclosed stake increased, decreased, or changed reporting status.
Class ownership
53%
Subject security Names, identifiers, and filing context for this profile. 2 source fields
Symbol
OMGAQ
Shares outstanding
55,351,475 shares
Source evidence Original filing metadata and source links for verification. 4 source fields
SEC form
SCHEDULE 13D/A
Accepted by SEC
05 Feb 2025, 16:40:53 UTC
Event date
03 Feb 2025
Source filing
View source filing

Key filing fact

Flagship V VentureLabs Rx Fund, L.P. disclosed 53% ownership in OMEGA THERAPEUTICS, INC. Common Stock, $0.001 par value per share (OMGAQ) on 03 Feb 2025.

Key facts

  • Flagship V VentureLabs Rx Fund, L.P. filed SCHEDULE 13D/A for OMEGA THERAPEUTICS, INC. Common Stock, $0.001 par value per share (OMGAQ).
  • Disclosed ownership: 53%.
  • Date of event: 03 Feb 2025.

Change

  • No earlier schedule filing is available for direct comparison.
  • Current filing was accepted on 05 Feb 2025, 16:40.

Research use

  • This page turns one Schedule 13D/G filing into a quick large-stake read before the raw reporting-person rows.
  • Use the linked SEC filing as the source of truth for ownership percentages, shares, and reporting-party details.

Evidence

Backed by Schedule 13D/13G

Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.

View source filing

Reporting persons

Disclosed reporting parties (17)

Names, ownership percentages, voting power, signatures, titles, and CIKs as disclosed in this Schedule 13D/G filing.

Name Ownership Shares owned Sole voting power Shared voting power Signature Title CIK
Flagship V VentureLabs Rx Fund, L.P. 2% 1,088,470 0 1,088,470 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager of General Partner 0001724939
Flagship Ventures Fund V, L.P. 11% 5,896,386 0 5,896,386 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager of General Partner 0001627639
Flagship Ventures Fund V General Partner LLC 13% 6,984,856 0 6,984,856 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager of General Partner 0001724575
Flagship Pioneering Fund VI, L.P. 16% 8,617,413 0 8,617,413 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager of General Partner 0001716926
Flagship Pioneering Fund VI General Partner LLC 16% 8,617,413 0 8,617,413 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager of General Partner 0001724957
Nutritional Health LTP Fund, L.P. 1.8% 970,588 0 970,588 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager of General Partner 0001780956
Nutritional Health LTP Fund General Partner LLC 1.8% 970,588 0 970,588 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager of General Partner 0001780951
Flagship Pioneering Special Opportunities Fund II, L.P. 14% 7,508,693 0 7,508,693 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager of General Partner 0001760283
Flagship Pioneering Special Opportunities Fund II General Partner LLC 14% 7,508,693 0 7,508,693 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager 0001826217
FPN, L.P. 2.9% 1,617,646 0 1,617,646 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager 0001860062
FPN General Partner LLC 2.9% 1,617,646 0 1,617,646 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager 0001860059
Flagship VentureLabs V, LLC 4% 2,197,059 0 2,197,059 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager 0001724959
Flagship VentureLabs V Manager LLC 4% 2,197,059 0 2,197,059 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager 0001768987
Flagship Pioneering Fund VII, L.P. 2.4% 1,329,324 0 1,329,324 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager 0001805916
Flagship Pioneering Fund VII General Partner LLC 2.4% 1,329,324 0 1,329,324 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer of Manager 0001805917
Flagship Pioneering, Inc. 40% 22,240,723 0 22,240,723 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Chief Executive Officer 0001400240
Noubar Afeyan 53% 29,225,579 0 29,225,579 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D. 0001222012
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