<SEC-DOCUMENT>0001104659-26-012138.txt : 20260209
<SEC-HEADER>0001104659-26-012138.hdr.sgml : 20260209
<ACCEPTANCE-DATETIME>20260209165551
ACCESSION NUMBER:		0001104659-26-012138
CONFORMED SUBMISSION TYPE:	S-8 POS
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20260209
DATE AS OF CHANGE:		20260209
EFFECTIVENESS DATE:		20260209

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Generation Bio Co.
		CENTRAL INDEX KEY:			0001733294
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				814301284
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		S-8 POS
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-269203
		FILM NUMBER:		26612270

	BUSINESS ADDRESS:	
		STREET 1:		301 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		857-529-5908

	MAIL ADDRESS:	
		STREET 1:		301 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
</SEC-HEADER>
<DOCUMENT>
<TYPE>S-8 POS
<SEQUENCE>1
<FILENAME>gbio-20260207xs8pos.htm
<DESCRIPTION>S-8 POS
<TEXT>
<!--Enhanced HTML document created with Toppan Merrill Bridge  11.2.0.21--><!--Created on: 2/7/2026 04:40:02 PM (UTC)--><html><head><meta charset="UTF-8"><title></title></head><body><div style="margin-top:30pt;"></div><div style="max-width:100%;padding-left:10.35%;padding-right:10.35%;position:relative;"><div style="clear:both;max-width:100%;position:relative;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">As filed with the Securities and Exchange Commission on February 9, 2026</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-239116</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-254429</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-262980</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-269203</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-277704</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-284123</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><b style="font-weight:bold;">Registration No. 333-287035</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:right;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;padding-bottom:1pt;padding-top:1pt;text-align:right;border-bottom:1.0pt solid #000000;border-top:3.0pt solid #000000;margin:0pt;"><font style="font-size:1pt;visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-size:18pt;font-weight:bold;">UNITED STATES</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-size:18pt;font-weight:bold;">SECURITIES AND EXCHANGE COMMISSION</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Washington, D.C. 20549</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div style="font-family:'Times New Roman','Times','serif';font-size:10.0pt;margin-bottom:0pt;margin-top:0pt;min-height:1.19em;position:relative;width:100%;"><hr noshade="true" color="#000000" size="1" style="background-color:#000000;color:#000000;height:1pt;position:relative;top:0.6em;width:100%;border:none;margin:0 auto;" align="center"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-239116</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-254429</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-262980</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-269203</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-277704</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-284123</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-287035</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="font-style:italic;font-weight:bold;">Under</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="font-style:italic;font-weight:bold;">The Securities Act of 1933</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div style="font-family:'Times New Roman','Times','serif';font-size:10.0pt;margin-bottom:0pt;margin-top:0pt;min-height:1.19em;position:relative;width:100%;"><hr noshade="true" color="#000000" size="1" style="background-color:#000000;color:#000000;height:1pt;position:relative;top:0.6em;width:100%;border:none;margin:0 auto;" align="center"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-size:24pt;font-weight:bold;">Generation Bio Co.</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(Exact name of registrant as specified in its charter)</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div style="font-family:'Times New Roman','Times','serif';font-size:10.0pt;margin-bottom:0pt;margin-top:0pt;min-height:1.19em;position:relative;width:100%;"><hr noshade="true" color="#000000" size="1" style="background-color:#000000;color:#000000;height:1pt;position:relative;top:0.6em;width:100%;border:none;margin:0 auto;" align="center"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div><table style="border-collapse:collapse;font-size:16pt;height:max-content;margin-left:auto;margin-right:auto;padding-left:0pt;padding-right:0pt;width:100%;" align="center"><tr style=""><td style="vertical-align:bottom;width:50.08%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Delaware</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:3.01%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><b style="font-weight:bold;">&#160;&#160;&#8203;&#160;&#8203;&#160;&#8203;</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:46.15%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">81-4301284</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:0.74%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><b style="font-weight:bold;">&#160;</b></p></td></tr><tr style=""><td style="vertical-align:bottom;width:50.08%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(State or other jurisdiction </b><b style="font-weight:bold;"><br></b><b style="font-weight:bold;">of</b> <b style="font-weight:bold;">incorporation or organization)</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:3.01%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:46.15%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(I.R.S. Employer</b> <br><b style="font-weight:bold;">Identification No.)</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:0.74%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:50.08%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:3.01%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:46.15%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:0.74%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:50.08%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;padding-left:7.2pt;text-align:center;text-indent:-7.2pt;margin:0pt;"><b style="font-weight:bold;">301 Binney Street</b> <br><b style="font-weight:bold;">Cambridge, Massachusetts</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:3.01%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:46.15%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt 3pt 0pt 0pt;"><b style="font-weight:bold;">02142</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:0.74%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:50.08%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;padding-left:7.2pt;text-align:center;text-indent:-7.2pt;margin:0pt;"><b style="font-weight:bold;">(Address of Principal Executive Offices)</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:3.01%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:46.15%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(Zip Code)</b></p></td><td style="vertical-align:bottom;white-space:nowrap;width:0.74%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p></td></tr></table></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Generation Bio Co. 2017 Stock Incentive Plan, as amended</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Generation Bio Co. 2020 Stock Incentive Plan</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Generation Bio Co. 2020 Employee Stock Purchase Plan</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Generation Bio Co. 2025 Inducement Stock Incentive Plan</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(Full title of the plans)</b></p><div style="font-family:'Times New Roman','Times','serif';font-size:10.0pt;margin-bottom:0pt;margin-top:0pt;min-height:1.19em;position:relative;width:100%;"><hr noshade="true" color="#000000" size="1" style="background-color:#000000;color:#000000;height:1pt;position:relative;top:0.6em;width:100%;border:none;margin:0 auto;" align="center"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Owen Hughes</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">XOMA Royalty Corporation</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">2200 Powell Street, Suite 310</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Emeryville, California 94608</b></p></div></div><hr style="background-color:#000000;clear:both;color:#000000;height:2pt;line-height:0;margin-bottom:30pt;margin-left:10.35%;margin-right:10.35%;margin-top:30pt;page-break-after:always;width:79.3%;border-width:0;"><div style="max-width:100%;padding-left:10.35%;padding-right:10.35%;position:relative;"><div style="clear:both;max-width:100%;position:relative;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(510)&#160;204-7200</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(Name, address, and telephone number, including area code, of agent for service)</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="font-weight:bold;visibility:hidden;">&#8203;</font></p><div style="font-family:'Times New Roman','Times','serif';font-size:10.0pt;margin-bottom:0pt;margin-top:0pt;min-height:1.19em;position:relative;width:100%;"><hr noshade="true" color="#000000" size="1" style="background-color:#000000;color:#000000;height:1pt;position:relative;top:0.6em;width:100%;border:none;margin:0 auto;" align="center"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="font-style:italic;font-weight:bold;">Copies to:</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Ryan A. Murr</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Branden C. Berns</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">Gibson, Dunn&#160;&amp; Crutcher LLP</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">One Embarcadero Center, Suite 2600</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">San Francisco, CA 94111</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">(415) 393-8200</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div style="font-family:'Times New Roman','Times','serif';font-size:10.0pt;margin-bottom:0pt;margin-top:0pt;min-height:1.19em;position:relative;width:100%;"><hr noshade="true" color="#000000" size="1" style="background-color:#000000;color:#000000;height:1pt;position:relative;top:0.6em;width:100%;border:none;margin:0 auto;" align="center"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of &#8220;large accelerated filer,&#8221; &#8220;accelerated filer,&#8221; &#8220;smaller reporting company,&#8221; and &#8220;emerging growth company&#8221; in Rule 12b-2 of the Exchange Act.</p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div><table style="border-collapse:collapse;font-size:16pt;height:max-content;margin-left:auto;margin-right:auto;padding-left:0pt;padding-right:0pt;width:100%;" align="center"><tr style=""><td style="vertical-align:bottom;width:38.96%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;padding-left:7.2pt;text-indent:-7.2pt;margin:0pt;">Large accelerated filer </p></td><td style="vertical-align:bottom;white-space:nowrap;width:6.14%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-family:'Segoe UI Symbol';">&#9744;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:52.65%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Accelerated&#160;filer</p></td><td style="vertical-align:bottom;white-space:nowrap;width:2.23%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-family:'Segoe UI Symbol';">&#9744;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:38.96%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:6.14%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:52.65%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:2.23%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:38.96%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;padding-left:7.2pt;text-indent:-7.2pt;margin:0pt;">Non-accelerated filer </p></td><td style="vertical-align:bottom;white-space:nowrap;width:6.14%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-family:'Segoe UI Symbol';">&#9746;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:52.65%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Smaller reporting company</p></td><td style="vertical-align:bottom;white-space:nowrap;width:2.23%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-family:'Segoe UI Symbol';">&#9746;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:38.96%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:6.14%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:52.65%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:2.23%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td></tr><tr style=""><td style="vertical-align:bottom;width:38.96%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:6.14%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></td><td style="vertical-align:bottom;white-space:nowrap;width:52.65%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Emerging growth company</p></td><td style="vertical-align:bottom;white-space:nowrap;width:2.23%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-family:'Segoe UI Symbol';">&#9744;</font></p></td></tr></table></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. <font style="font-family:'Segoe UI Symbol';">&#9744;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="font-family:'Segoe UI Symbol';visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;padding-bottom:1pt;padding-top:1pt;border-bottom:3.0pt solid #000000;border-top:1.0pt solid #000000;margin:0pt;"><font style="font-size:1pt;visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="display:none;font-family:'Times New Roman','Times','serif';line-height:0pt;margin:0pt;"><font style="font-size:0pt;visibility:hidden;">&#8203;</font></p></div></div><hr style="background-color:#000000;clear:both;color:#000000;height:2pt;line-height:0;margin-bottom:30pt;margin-left:10.35%;margin-right:10.35%;margin-top:30pt;page-break-after:always;width:79.3%;border-width:0;"><div style="max-width:100%;padding-left:10.35%;padding-right:10.35%;position:relative;"><div style="clear:both;max-width:100%;position:relative;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt 0pt 12pt 0pt;"><b style="font-weight:bold;">DEREGISTRATION OF SECURITIES</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt 0pt 12pt 0pt;">These Post-Effective Amendments (these &#8220;<u style="text-decoration-color:#000000;text-decoration-line:underline;text-decoration-style:solid;">Post-Effective Amendments</u>&#8221;) filed by Generation Bio Co. (the &#8220;<u style="text-decoration-color:#000000;text-decoration-line:underline;text-decoration-style:solid;">Registrant</u>&#8221;) relate to the following registration statements on Form S-8 (together, the &#8220;<u style="text-decoration-color:#000000;text-decoration-line:underline;text-decoration-style:solid;">Registration Statements</u>&#8221;):</p><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:12pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">1.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000119312520167243/d945179ds8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-239116, registering (i) 479,338 shares of common stock, $0.0001 par value per share, of the Registrant (&#8220;Common Stock&#8221;) issuable under the Registrant&#8217;s 2017 Stock Incentive Plan (the &#8220;2017 Plan&#8221;); (ii) 492,732 shares of Common Stock issuable under the Registrant&#8217;s 2020 Stock Incentive Plan (the &#8220;2020 Plan&#8221;); and (iii) 48,123 shares of Common Stock issuable under the Registrant&#8217;s 2020 Employee Stock Purchase Plan (the &#8220;2020 ESPP&#8221;), which was filed with the U.S. Securities and Exchange Commission (the &#8220;SEC&#8221;) on June 12, 2020.</font></a></td></tr></table><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:12pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">2.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000155837021003181/tmb-20210318xs8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-254429, registering (i) 187,880 shares of Common Stock issuable under the 2020 Plan and (ii) 46,970 shares of Common Stock issuable under the Registrant&#8217;s 2020 ESPP, which was filed with the SEC on March 18, 2021.</font></a></td></tr></table><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:12pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">3.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000155837022001964/tmb-20220224xs8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-262980, registering (i) 227,922 shares of Common Stock issuable under the 2020 Plan and (ii) 56,980 shares of Common Stock issuable under the 2020 ESPP, which was filed with the SEC on February 24, 2022.</font></a></td></tr></table><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:12pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">4.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000155837023000232/tmb-20230112xs8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-269203, registering an aggregate of (i) 246,832 shares of Common Stock issuable under the 2020 Plan and (ii) 59,505 shares of Common Stock issuable under the 2020 ESPP, which was filed with the SEC on January 12, 2023.</font></a></td></tr></table><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:12pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">5.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000155837024002617/tmb-20240306xs8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-277704, registering an aggregate of (i) 277,565 shares of Common Stock issuable under the 2020 Plan and (ii) 66,218 shares of Common Stock issuable under the 2020 ESPP, which was filed with the SEC on March 6, 2024.</font></a></td></tr></table><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:12pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">6.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000155837025000018/tmb-20250103xs8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-284123, registering an aggregate of (i) 276,416 shares of Common Stock issuable under the 2020 Plan and (ii) 66,980 shares of Common Stock issuable under the 2020 ESPP, which was filed with the SEC on January 3, 2025.</font></a></td></tr></table><table border="0" cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:'Times New Roman','Times','serif';font-size:10pt;margin-bottom:0pt;margin-top:0pt;table-layout:fixed;width:100%;border:0pt;"><tr><td style="font-family:'Times New Roman','Times','serif';font-size:10pt;vertical-align:text-top;white-space:nowrap;width:18pt;padding:0pt;">7.</td><td style="padding:0pt;"><a style="font-family:&quot;'Times New Roman','Times','serif'&quot;;font-size:10pt;" href="https://www.sec.gov/Archives/edgar/data/1733294/000155837025006749/gbio-20250507xs8.htm"><font style="font-family:'Times New Roman','Times','serif';font-style:normal;font-weight:normal;">Registration Statement No. 333-287035, registering up to 125,000 shares of Common Stock issuable under the Registrant&#8217;s 2025 Inducement Stock Incentive Plan, which was filed with the SEC on May 7, 2025.</font></a></td></tr></table><div style="margin-top:12pt;"></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt 0pt 12pt 0pt;">All share numbers set forth above reflect a 1-for-10 reverse stock split of Common Stock that became effective on July 21, 2025.</p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt 0pt 12pt 0pt;">On February 9, 2026, pursuant to the Agreement and Plan of Merger, dated as of December 15, 2025 (the &#8220;<u style="text-decoration-color:#000000;text-decoration-line:underline;text-decoration-style:solid;">Merger Agreement</u>&#8221;), by and among the Registrant, XOMA Royalty Corporation, a Nevada corporation (&#8220;<u style="text-decoration-color:#000000;text-decoration-line:underline;text-decoration-style:solid;">Parent</u>&#8221;) and XRA 7 Corp., a Delaware corporation and a wholly owned subsidiary of Parent (&#8220;<u style="text-decoration-color:#000000;text-decoration-line:underline;text-decoration-style:solid;">Merger Sub</u>&#8221;), Merger Sub merged with and into the Registrant, with the Registrant surviving as a wholly-owned subsidiary of Parent.</p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt 0pt 12pt 0pt;">As a result of the transactions contemplated by the Merger Agreement, the Registrant has terminated any and all offerings and sales of securities pursuant to the Registration Statements. In accordance with the undertakings made by the Registrant in the Registration Statements to remove from registration, by means of a post-effective amendment, any of the securities of the Registrant registered under the Registration Statements which remain unsold at the termination of the offerings, the Registrant hereby terminates the effectiveness of the Registration Statements and removes from registration all of the securities that remain unsold under the Registration Statements as of the date hereof, if any. The Registrant is filing these Post-Effective Amendments to withdraw and remove from registration all securities registered pursuant to the Registration Statements that remain unsold as of the date hereof. The Registration Statements are hereby amended, as appropriate, to reflect the deregistration of such securities. After giving effect to these Post-Effective Amendments, there will be no remaining securities registered by the Registrant pursuant to the Registration Statements.</p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p></div></div><hr style="background-color:#000000;clear:both;color:#000000;height:2pt;line-height:0;margin-bottom:30pt;margin-left:10.35%;margin-right:10.35%;margin-top:30pt;page-break-after:always;width:79.3%;border-width:0;"><div style="max-width:100%;padding-left:10.35%;padding-right:10.35%;position:relative;"><div style="clear:both;max-width:100%;position:relative;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;text-align:center;margin:0pt;"><b style="font-weight:bold;">SIGNATURE</b></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused these Post-Effective Amendments to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Emeryville, State of California, on February 9, 2026.</p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><div align="left"><table style="border-collapse:collapse;font-size:16pt;height:max-content;padding-left:0pt;padding-right:0pt;width:98%;"><tr style=""><td colspan="2" style="vertical-align:top;width:100%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><b style="font-weight:bold;">GENERATION BIO CO.</b></p></td></tr><tr style=""><td style="vertical-align:middle;width:5.67%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">&#160;</p></td><td style="vertical-align:middle;width:94.32%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">&#160;</p></td></tr><tr style=""><td style="vertical-align:top;width:5.67%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">By:</p></td><td style="vertical-align:bottom;width:94.32%;border-bottom:1.0pt solid #000000;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">/s/ Owen Hughes</p></td></tr><tr style=""><td style="vertical-align:bottom;width:5.67%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Name:</p></td><td style="vertical-align:bottom;width:94.32%;border-top:1.0pt solid #000000;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Owen Hughes</p></td></tr><tr style=""><td style="vertical-align:bottom;width:5.67%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Title:</p></td><td style="vertical-align:bottom;width:94.32%;margin:0pt;padding:0pt;"><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">President, Treasurer and Secretary</p></td></tr></table></div><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;"><font style="visibility:hidden;">&#8203;</font></p><p style="font-family:'Times New Roman','Times','serif';font-size:10pt;margin:0pt;">Pursuant to Rule 478 under the Securities Act of 1933, as amended, no other person is required to sign these Post-Effective Amendments.</p></div></div><hr style="background-color:#000000;clear:both;color:#000000;height:2pt;line-height:0;margin-left:10.35%;margin-right:10.35%;margin-top:30pt;page-break-after:avoid;width:79.3%;border-width:0;"></body></html>
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</DOCUMENT>
</SEC-DOCUMENT>
