Aspasia Vahaviolos holds 6.1M Mistras shares (MG) — 19.32% stake

Rhea-AI Filing Summary

Mistras Group reports a 6,105,650-share beneficial holding by Aspasia Vahaviolos. The filing states this equals 19.32% of the class based on 31,595,562 outstanding shares as of March 9, 2026. The position includes 854,292 shares held directly and 5,251,358 shares held in a grantor retained annuity trust where the trustee (the Reporting Person's daughter) currently holds voting and dispositive power; the Reporting Person may be deemed the beneficial owner because of a potential right to re-acquire the Trust shares within sixty days.

Insights

Corporate Governance Analyst

Large passive ownership disclosed with trust voting control noted.

The Schedule 13G shows 6,105,650 shares beneficially owned, representing 19.32% of the outstanding common stock as of March 9, 2026. The split between direct and trust holdings and the trustee's voting power are explicitly described.

Because the trust's trustee holds voting and dispositive authority, governance influence exists in practice; the filing also notes a conditional right to re-acquire shares within sixty days, which is relevant to control analysis and potential Section 13 reporting obligations.

Equity Ownership Specialist

Position size is material but the filing is a standard beneficial-ownership disclosure.

The disclosed 19.32% stake is large relative to total outstanding shares and is broken down into 854,292 direct and 5,251,358 trust-held shares. The filing cites the specific outstanding-share base used for the percentage.

Investor impact depends on whether the trust's voting arrangements change or shares are re-acquired within sixty days; subsequent filings would show any change in status or voting alignment.

Key Figures

Beneficial ownership: 6,105,650 shares Direct holdings: 854,292 shares Trust holdings: 5,251,358 shares +2 more

5 metrics

Beneficial ownership 6,105,650 shares Total shares beneficially owned reported in Schedule 13G

Direct holdings 854,292 shares Shares held directly by the Reporting Person

Trust holdings 5,251,358 shares Shares held in a grantor retained annuity trust

Outstanding shares used 31,595,562 shares Shares outstanding as of <date>March 9, 2026</date> used for percentage calculation

Percent of class 19.32% Percent of outstanding shares represented by the beneficial ownership

Key Terms

grantor retained annuity trust, beneficial ownership, CUSIP

3 terms

grantor retained annuity trust financial

"5,251,358 shares held in a grantor retained annuity trust (the "Trust")"

A grantor retained annuity trust (GRAT) is an estate-planning tool where the person who creates the trust transfers assets into it but receives fixed cash payments (an annuity) from the trust for a set number of years; whatever remains after that term passes to designated beneficiaries. It matters to investors because it can shift future appreciation of assets out of the creator’s taxable estate—like putting an asset into a timed vending machine that pays you fixed amounts while any extra value that grows inside the machine goes to heirs with reduced gift or estate tax consequences.

beneficial ownership regulatory

"Amount beneficially owned: 6,105,650*"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

CUSIP market

"CUSIP Number(s): 60649T107"

A CUSIP is a nine-character alphanumeric code that uniquely identifies a U.S. or Canadian financial security—such as a stock, bond, or fund share—like a Social Security number for an investment. It matters to investors because brokers, exchanges and record-keepers use the CUSIP to match trades, track ownership, settle transactions and pull accurate records, reducing errors and ensuring money and securities go to the right place.

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)

12/31/2025

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 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 854,292.00
6	Shared Voting Power 5,251,358.00
7	Sole Dispositive Power 854,292.00
8	Shared Dispositive Power 5,251,358.00

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)

19.32 %

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: 7 Ridgeview Road Princeton, NJ 08540
(c)	Citizenship: United States of America
(d)	Title of class of securities: Common Stock, $0.01 par value
(e)	CUSIP Number(s): 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* * The 6,105,650 shares reported as beneficially owned by the Reporting Person consists of (i) 854,292 shares held directly by the Reporting Person and (ii) 5,251,358 shares held in a grantor retained annuity trust (the "Trust"). The Reporting Person's daughter, who does not reside with her, is the trustee for the Trust and currently holds power over the voting and disposition of the shares of common stock held by the Trust. The Reporting Person may be deemed to have beneficial ownership of the shares held by the Trust because of a potential right to re-acquire the shares within sixty days.
(b)	Percent of class: 19.32%* * This percentage calculation is based on 31,595,562 outstanding shares as of March 9, 2026 as reported by the issuer.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 854,292
	(ii) Shared power to vote or to direct the vote: 5,251,358
	(iii) Sole power to dispose or to direct the disposition of: 854,292
	(iv) Shared power to dispose or to direct the disposition of: 5,251,358
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
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:	/s/Aspasia Vahaviolos
Name/Title:	Aspasia Vahaviolos
Date:	03/31/2026

FAQ

What stake does Aspasia Vahaviolos hold in Mistras Group (MG)?

She reports beneficial ownership of 6,105,650 shares, equal to 19.32% of the class. This percentage uses 31,595,562 outstanding shares as of March 9, 2026 as the basis.

How are Ms. Vahaviolos's shares held and voted?

She holds 854,292 shares directly and 5,251,358 shares in a grantor retained annuity trust. The trustee (her daughter) currently holds voting and dispositive power over the trust shares.

Why might Ms. Vahaviolos be deemed the beneficial owner of trust shares?

The filing states she has a potential right to re-acquire the trust shares within sixty days, which can create beneficial ownership under disclosure rules.

What outstanding share figure was used to calculate the 19.32% stake?

The percentage is calculated using 31,595,562 outstanding shares as of March 9, 2026, as reported by the issuer and cited in the filing.