UNITED STATES

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G/A

(Amendment No. 1)*

Under the Securities Exchange Act of 1934

MAINZ BIOMED N.V.

(Name of Issuer)

Ordinary Shares, nominal value of €0.01 per share

(Titles of Class of Securities)

N5436L101

(CUSIP Number)

December 31, 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)

x 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 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, as amended (the “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. N5436L101 SCHEDULE 13G Page 2 of 6

1	NAME OF REPORTING PERSON OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON KfW
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨ (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Germany

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 1,237,501
	6	SHARED VOTING POWER 0
	7	SOLE DISPOSITIVE POWER 1,237,501
	8	SHARED DISPOSITIVE POWER 0

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,237,501
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 6.4% (1)
12	TYPE OF REPORTING PERSON OO

(1) Calculated based on 16,998,815 ordinary shares of Mainz Biomed N.V. outstanding as of November 13, 2023, as disclosed in its prospectus supplement filed with the Securities and Exchange Commission on November 13, 2023.

CUSIP No. N5436L101 SCHEDULE 13G Page 3 of 6

Item 1(a).	Name of Issuer:
	Mainz Biomed N.V.
Item 1(b).	Address of Issuer’s Principal Executive Offices:
	Robert Koch Strasse 50, 55129 Mainz, Germany
Item 2(a).	Name of Person Filing:
	Kreditanstalt für Wiederaufbau
Item 2(b).	Address of Principal Business Office or, if none, Residence:
	Palmengartenstrasse 5-9, 60325 Frankfurt am Main, Germany
Item 2(c).	Citizenship:
	Germany
Item 2(d).	Titles of Classes of Securities:
	Ordinary Shares, nominal value of €0.01 per share
Item 2(e).	CUSIP Number:
	N5436L101

Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a(n):

(a)	¨	Broker or dealer registered under Section 15 of the Exchange Act (15 U.S.C. 78o).
(b)	¨	Bank as defined in Section 3(a)(6) of the Exchange Act (15 U.S.C. 78c).

CUSIP No. N5436L101 SCHEDULE 13G Page 4 of 6

(c)	☐	Insurance company as defined in Section 3(a)(19) of the Exchange Act (15 U.S.C. 78c).
(d)	☐	Investment company registered under Section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).
(e)	☐	Investment adviser in accordance with §240.13d-1(b)(1)(ii)(E).
(f)	☐	Employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F).
(g)	☐	Parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G).
(h)	☐	Savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813).
(i)	☐	Church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3).
(j)	☐	Non-U.S. institution, in accordance with § 240.13d-1(b)(1)(ii)(J).
(k)	☐	Group in accordance with §240.13d-1(b)(1)(ii)(K).
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:
	See response to Item 9 on the cover page.
(b)	Percent of class:
	See response to Item 11 on the cover page.
(c)	Number of shares as to which such person has:

(i)	Sole power to vote or to direct the vote:
	See response to Item 5 on the cover page.
(ii)	Shared power to vote or to direct the vote:
	See response to Item 6 on the cover page.

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(iii)	Sole power to dispose or to direct the disposition of:
	See response to Item 7 on the cover page.
(iv)	Shared power to dispose or to direct the disposition of:
	See response to Item 8 on the cover page.

Item 5.	Ownership of Five Percent or Less of a Class.
	If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following ¨.
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.
	Not Applicable.

CUSIP No. N5436L101 SCHEDULE 13G Page 6 of 6

SIGNATURE

After reasonable inquiry and to the best of our knowledge and belief, the undersigned hereby certify on behalf of KfW that the information set forth in this statement is true, complete and correct.

Dated: February 13, 2024

KfW
By:	/s/ Dr. Wolfgang Richter
Name:	Dr. Wolfgang Richter
Title:	First Vice President
By:	/s/ Petra Röttcher
Name:	Petra Röttcher
Title:	Vice President