Form 4 - Statement of changes in beneficial ownership of securities:
SEC Accession No. 0001231919-26-000124
Filing Date
2026-02-09
Accepted
2026-02-09 18:19:16
Documents
1
Period of Report
2026-02-09

Document Format Files

Seq Description Document Type Size
1 form4-02092026_110208.html 4  
1 form4-02092026_110208.xml 4 15826
  Complete submission text file 0001231919-26-000124.txt   20426
Mailing Address 400 TECHNOLOGY SQUARE 10TH FLOOR CAMBRIDGE MA 02139
Business Address 400 TECHNOLOGY SQUARE 10TH FLOOR CAMBRIDGE MA 02139 857-201-2700
Atlas Venture Fund X, L.P. (Reporting) CIK: 0001628098 (see all company filings)

State of Incorp.: DE | Fiscal Year End: 1231
Type: 4 | Act: 34 | File No.: 001-39319 | Film No.: 26612862

Mailing Address 301 BINNEY STREET CAMBRIDGE MA 02142
Business Address 301 BINNEY STREET CAMBRIDGE MA 02142 857-529-5908
Generation Bio Co. (Issuer) CIK: 0001733294 (see all company filings)

EIN.: 814301284 | Fiscal Year End: 1231
SIC: 2834 Pharmaceutical Preparations
(CF Office: 03 Life Sciences)

Mailing Address 400 TECH. SQ. 10TH FLOOR CAMBRIDGE MA 02139
Business Address 400 TECH. SQ. 10TH FLOOR CAMBRIDGE MA 02139 857-201-2700
Atlas Venture Associates X, LLC (Reporting) CIK: 0001742765 (see all company filings)

State of Incorp.: DE | Fiscal Year End: 1231
Type: 4 | Act: 34 | File No.: 001-39319 | Film No.: 26612860

Mailing Address 400 TECHNOLOGY SQ. 10TH FLOOR CAMBRIDGE MA 02139
Business Address 400 TECHNOLOGY SQ. 10TH FLOOR CAMBRIDGE MA 02139 857-201-2700
ATLAS VENTURE ASSOCIATES X, L.P. (Reporting) CIK: 0001742766 (see all company filings)

State of Incorp.: DE
Type: 4 | Act: 34 | File No.: 001-39319 | Film No.: 26612861

Mailing Address 400 TECHNOLOGY SQUARE, 10TH FLOOR CAMBRIDGE MA 02139
Business Address 400 TECHNOLOGY SQUARE, 10TH FLOOR CAMBRIDGE MA 02139 857-201-2700
Atlas Venture Opportunity Fund I, L.P. (Reporting) CIK: 0001759241 (see all company filings)

State of Incorp.: DE | Fiscal Year End: 1231
Type: 4 | Act: 34 | File No.: 001-39319 | Film No.: 26612859

Mailing Address 400 TECHNOLOGY SQUARE 10TH FLOOR CAMBRIDGE MA 02139
Business Address 400 TECHNOLOGY SQUARE 10TH FLOOR CAMBRIDGE MA 02139 857-201-2700
Atlas Venture Associates Opportunity I, L.P. (Reporting) CIK: 0001780065 (see all company filings)

State of Incorp.: DE | Fiscal Year End: 1231
Type: 4 | Act: 34 | File No.: 001-39319 | Film No.: 26612858

Mailing Address 400 TECHNOLOGY SQUARE 10TH FLOOR CAMBRIDGE MA 02139
Business Address 400 TECHNOLOGY SQUARE 10TH FLOOR CAMBRIDGE MA 02139 857-201-2700
Atlas Venture Associates Opportunity I, LLC (Reporting) CIK: 0001780066 (see all company filings)

State of Incorp.: DE | Fiscal Year End: 1231
Type: 4 | Act: 34 | File No.: 001-39319 | Film No.: 26612857