Individual Reports 6.1M Shares in Mistras Group, Representing 19.4%

Rhea-AI Filing Summary

A Schedule 13G filed for Mistras Group, Inc. reports that Aspasia Vahaviolos beneficially owns 6,105,650 shares of the company’s common stock, representing 19.4% of the class based on 31,538,050 outstanding shares as of August 6, 2025. The filing states Ms. Vahaviolos has sole voting and dispositive power over these shares and certifies the holdings were not acquired to change or influence control of the issuer. The document includes an executed power of attorney and identifies the issuer’s principal office in Princeton Junction, New Jersey.

Positive

• Clear, specific disclosure of beneficial ownership showing 6,105,650 shares held
• Material stake reported at 19.4% of outstanding common stock (basis: 31,538,050 shares)
• Sole voting and dispositive power reported, providing clarity on control over the shares
• Certification included stating shares were not acquired to change or influence control

Negative

• None.

Insights

Securities Analyst

TL;DR: A nearly 20% stake by an individual signals a material ownership position that investors should note.

The filing documents a clear, sizeable beneficial ownership position: 6,105,650 shares, or 19.4% of outstanding common stock (31,538,050 shares basis). Ownership is reported as sole voting and dispositive power, which means the reporting person can unilaterally vote and sell these shares. The certification asserts the shares were not acquired to effect control.

Corporate Governance Expert

TL;DR: Ownership near 20% has governance significance and may affect board and shareholder dynamics.

The report shows a single individual holding a significant minority stake with sole voting/dispositive authority. While the filer certified no intent to change control, a 19.4% position is material for governance discussions and could influence shareholder proposals or nominations depending on subsequent actions. The filing includes a power of attorney authorizing the signature.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Mistras Group, Inc.

(Name of Issuer)

Common Stock, $0.01 par value

(Title of Class of Securities)

60649T107

(CUSIP Number)

05/23/2025

(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)

SCHEDULE 13G

CUSIP No. 60649T107

1

Names of Reporting Persons

Aspasia Vahaviolos

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 6,105,650.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 6,105,650.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

6,105,650.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

19.4 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Mistras Group, Inc.
(b)	Address of issuer's principal executive offices: 195 Clarksville Road, Princeton Junction, NJ, 08550
Item 2.
(a)	Name of person filing: Aspasia Vahaviolos
(b)	Address or principal business office or, if none, residence: c/o Stephanie Foglia, Mistras Group, 195 Clarksville Road, Princeton Junction, New Jersey 08550
(c)	Citizenship: United States of America
(d)	Title of class of securities: Common Stock, $0.01 par value
(e)	CUSIP No.: 60649T107
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: 6,105,650.00
(b)	Percent of class: 19.4%* *This percentage calculation is based on 31,538,050 outstanding shares as of August 6, 2025.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 6,105,650.00
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 6,105,650.00
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 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 or Control Person.
	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.

Certifications:

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.

Aspasia Vahaviolos

Signature:	Michael C. Keefe
Name/Title:	Michael C. Keefe as attorney-in-fact for Aspasia Vahaviolos
Date:	09/11/2025

Exhibit Information

EX-24.1 Power of Attorney

FAQ

How many Mistras Group (MG) shares does Aspasia Vahaviolos own?

The filing reports 6,105,650 shares beneficially owned by Aspasia Vahaviolos.

What percentage of Mistras Group does the 13G filing report for Aspasia Vahaviolos?

The filing reports ownership equal to 19.4% of the outstanding common stock (based on 31,538,050 shares).

Does Aspasia Vahaviolos have voting power over the reported MG shares?

Yes. The filing states she has sole voting power and sole dispositive power over all 6,105,650 shares.

Was the stake reported to be acquired to change or influence control of Mistras Group?

No. The certification in Item 10 states the securities were not acquired and are not held to change or influence control of the issuer.

What supporting documentation is attached to the Schedule 13G filing?

The filing lists Exhibit EX-24.1, a Power of Attorney, as supporting documentation.