# EDGAR Filing Document

**Accession Number:** 0001345099
**File Stem:** 0001140361-25-035151
**Filing Date:** 2025-9
**Character Count:** 10772
**Document Hash:** a01e4973d4cac3c6cabf772df019257d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001140361-25-035151.hdr.sgml**: 20250916

**ACCESSION NUMBER**: 0001140361-25-035151

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250916

**DATE AS OF CHANGE**: 20250916

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MESOBLAST LTD
- **CENTRAL INDEX KEY:** 0001345099
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** C3
- **FISCAL YEAR END:** 0630

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-89380
- **FILM NUMBER:** 251318463

**BUSINESS ADDRESS:**
- **STREET 1:** LEVEL 38
- **STREET 2:** 55 COLLINS STREET
- **CITY:** MELBOURNE, VICTORIA
- **STATE:** C3
- **ZIP:** 3000
- **BUSINESS PHONE:** 613 9639 6036

**MAIL ADDRESS:**
- **STREET 1:** LEVEL 38
- **STREET 2:** 55 COLLINS STREET
- **CITY:** MELBOURNE, VICTORIA
- **STATE:** C3
- **ZIP:** 3000
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Gueck William J.
- **CENTRAL INDEX KEY:** 0002085232

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G

**MAIL ADDRESS:**
- **STREET 1:** 54 ROAN LANE
- **CITY:** ST. LOUIS
- **STATE:** MO
- **ZIP:** 63124

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**Issuer:** MESOBLAST LTD

**Title of Class of Securities:** Ordinary Shares

**CUSIP Number:** 590717401

**Date of Event Which Requires Filing of this Statement:** 09/12/2025

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

- [ ] Rule 13d-1(b)

- [x] Rule 13d-1(c)

- [ ] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>Gueck William J. | Names of Reporting Persons<br>Gueck William J. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>525000 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>63996900 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>525000 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>63996900 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>64521900 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>64521900 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>5% | Percent of Class Represented by Amount in Row (9)<br>5% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** (1) The number of Ordinary Shares reported is as of September 12, 2025. The Reporting Person is the sole beneficial owner of 525,000 Ordinary Shares held in the form of American Depositary Receipts ("ADRs"). The Reporting Person also has discretionary authority to vote and dispose, and may be deemed to be the beneficial owner, of: (i) 1,792,150 Ordinary Shares held in the form of ADRs by Conrad Gueck; (ii) 1,792,150 Ordinary Shares held in the form of ADRs by Ava Gueck; (iii) 1,110,000 Ordinary Shares held in the form of ADRs by the Mary DeAnn Gueck trust, for which the Reporting Person is trustee; (iv) 890,000 Ordinary Shares held in the form of ADRs by the William Gueck trust, for which Mary DeAnn Gueck is trustee. In addition, the Reporting Person has discretionary authority to vote and dispose of (A) 49,717,450 Ordinary Shares held in the form of ADRs by Cova Holdings LP and (B) 350,000 Ordinary Shares in the form of ADRs underlying warrants that Cova Holdings LP has the right to acquire through the exercise of such warrants within 60 days, and may be deemed to be the beneficial owner of these shares. In addition, the Reporting Person has discretionary authority to vote and dispose of 8,345,150 Ordinary Shares held in the form of ADRs by AVCO Holdings LP and may be deemed to be the beneficial owner of these shares.

---

**Item 1(a). Name of Issuer:**
MESOBLAST LTD

**Item 1(b). Address of Issuer's Principal Executive Offices:**
Level 38, 55 Collins Street, Melbourne, VIC, Australia, 3000

**Item 2(a). Name of Person Filing:**
This statement is filed by Dr. William Gueck (the "Reporting Person").

**Item 2(b). Address of Principal Business Office:**
Dr. William Gueck
54 Roan Ln
St. Louis, MO, 63124

**Item 2(c). Citizenship:**
Dr. William Gueck is a citizen of the United States of America.

**Item 2(d). Title of Class of Securities:**
Ordinary Shares

**Item 2(e). CUSIP Number:**
590717401

**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 (15 U.S.C. 78o).

(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c) [ ] Insurance company as defined in section 3(a)(19) of the 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) [ ] An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f) [ ] An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g) [ ] A parent holding company or control person in accordance with § 240.13d-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 (15 U.S.C. 80a-3);

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

(k) [ ] Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

**Item 4. Ownership:**

**(a) Amount beneficially owned:**

The percentages used herein are calculated based upon 1,281,167,187 Ordinary Shares issued and outstanding as of August 25, 2025, based on information provided by an officer of the Issuer in an email correspondence on August 25, 2025.
The information required by Items 4(a)-(c), as of the date hereof, is set forth in Rows 5-11 of the cover page hereto for the Reporting Person and is incorporated herein by reference.
The Reporting Person's total beneficial ownership amounts to 64,521,900 Ordinary Shares held in the form of ADRs (constituting approximately 5.0% of the Ordinary Shares outstanding).
The Reporting Person is the sole beneficial owner of 525,000 Ordinary Shares held in the form of ADRs. The Reporting Person also has discretionary authority to vote and dispose, and may be deemed to be the beneficial owner, of: (i) 1,792,150 Ordinary Shares held in the form of ADRs by Conrad Gueck; (ii) 1,792,150 Ordinary Shares held in the form of ADRs by Ava Gueck; (iii) 1,110,000 Ordinary Shares held in the form of ADRs by the Mary DeAnn Gueck trust, for which the Reporting Person is trustee; (iv) 890,000 Ordinary Shares held in the form of ADRs by the William Gueck trust, for which Mary DeAnn Gueck is trustee. In addition, the Reporting Person has discretionary authority to vote and dispose of (A) 49,717,450 Ordinary Shares held in the form of ADRs by Cova Holdings LP and (B) 350,000 Ordinary Shares in the form of ADRs underlying warrants that Cova Holdings LP has the right to acquire through the exercise of such warrants within 60 days, and may be deemed to be the beneficial owner of these shares. In addition, the Reporting Person has discretionary authority to vote and dispose of 8,345,150 Ordinary Shares held in the form of ADRs by AVCO Holdings LP and may be deemed to be the beneficial owner of these shares. Although the Reporting Person may be deemed to have beneficial ownership of such Ordinary Shares, neither the filing of this Schedule 13G nor any of the contents hereof shall be deemed to constitute an admission by the Reporting Person that he is the beneficial owner of any of the Ordinary Shares owned by Cova Holdings LP and by AVCO Holdings LP for purposes of Section 13(d) of the Act, or for any other purpose, and such beneficial ownership is expressly disclaimed.

**(b) Percent of class:**

N/A

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

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

N/A

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

N/A

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

N/A

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

N/A

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

[x] 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 5 Percent on Behalf of Another Person.**

Not Applicable

**Item 7. Identification and Classification of the Subsidiary**

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.

**Gueck William J.**

**Date:** 09/16/2025

**By:** /s/ William Gueck

**Name & Title:** Dr. William Gueck