Generation Bio (GBIO) SC 13G Generation Bio / ModernaTX ownership change

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. _) *

Generation Bio Co.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

37148K100

(CUSIP Number)

March 24, 2023

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☒ Rule 13d-1(c)

☐ Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 37148K100

1.	Names of Reporting Person   ModernaTX, Inc.
2.	Check the Appropriate Box if a Member of a Group (See Instructions)   (a)  ☐        (b)  ☐
3.	SEC Use Only
4.	Citizenship or Place of Organization   Delaware

Number of Shares  Beneficially  Owned by Each Reporting Person With	5.	Sole Voting Power   5,859,375
	6.	Shared Voting Power   0
	7.	Sole Dispositive Power   5,859,375
	8.	Shared Dispositive Power   0

9.	Aggregate Amount Beneficially Owned by Each Reporting Person   5,859,375
10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)   ☐
11.	Percent of Class Represented by Amount in Row (9)   8.9% (1)
12.	Type of Reporting Person (See Instructions)   CO

(1) Percentage ownership is calculated based on 65,525,133 shares of Common Stock outstanding, consisting of the 5,859,375 shares of Common Stock issued to the Reporting Person and the 59,665,758 shares of Common Stock outstanding as of February 17, 2023 reported in the Issuer’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 23, 2023.

Item 1.

(a) Name of Issuer

Generation Bio Co. (the “Issuer”)

(b) Address of Issuer’s Principal Executive Offices

301 Binney Street

Cambridge, MA 02142-1071

Item 2.

(a) Name of Person Filing

ModernaTX, Inc.

(b) Address of Principal Business Office or, if none, Residence

c/o Moderna, Inc.

200 Technology Square

Cambridge, MA 02139

(c) Citizenship

Delaware

(d) Title of Class of Securities

Common Stock, $0.0001 par value per share

(e) CUSIP Number

37148K100

Item 3. If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)	☐	Broker or dealer registered under Section 15 of the Act;
(b)	☐	Bank as defined in Section 3(a)(6) of the Act;
(c)	☐	Insurance company as defined in Section 3(a)(19) of the Act;
(d)	☐	Investment company registered under Section 8 of the Investment Company Act of 1940;
(e)	☐	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);
(f)	☐	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);
(g)	☐	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);
(h)	☐	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	☐	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940;
(j)	☐	A non-U.S. institution in accordance with Rule 240.13d-1(b)(1)(ii)(J);
(k)	☐	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with Rule 240.13d-1(b)(1)(ii)(J), please specify the type of institution:

If filing as a non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J), please specify the type of institution:

Item 4. Ownership

(a) Amount beneficially owned:

5,859,375

(b) Percent of class: 8.9%(1)

(c) Number of shares as to which the person has:

(i) Sole power to vote or to direct the vote:

5,859,375

(ii) Shared power to vote or to direct the vote:

0

(iii) Sole power to dispose or to direct the disposition of:

5,859,375

(iv) Shared power to dispose or to direct the disposition of:

0

Item 5. Ownership of Five Percent or Less of a Class

Not applicable.

Item 6. Ownership of More than Five Percent on Behalf of Another Person

Not applicable.

Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company

Not applicable.

Item 8. Identification and Classification of Members of the Group

Not applicable.

Item 9. Notice of Dissolution of Group

Not applicable.

Item 10. Certification

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 24, 2023	MODERNATX, INC.
	By:	/s/ Brian Sandstrom
	Name:	Brian Sandstrom
	Title:	Vice President, Associate General Counsel, Securities