Mistras Group (MG) amends filing to show 1.62M shares; 5.12% stake

Rhea-AI Filing Summary

Mistras Group, Inc. amendment to a Schedule 13G/A corrects the previously reported beneficial ownership for Kristy Kyriakopoulos to 1,617,006 shares, representing 5.12% of the company's common stock. The filing states the 31,595,562 shares outstanding as of March 9, 2026 used for the percentage calculation.

The amendment is described as administrative and does not change other information in the original filing.

Insights

Corporate Governance Analyst

Amendment corrects ownership disclosure; no new trading signal.

The Schedule 13G/A amendment restates the reporting person's beneficial ownership as 1,617,006 shares and the issuer's outstanding share base as 31,595,562 shares as of March 9, 2026. This is an administrative correction rather than a new acquisition or disposition.

Because the filing updates disclosure without reporting recent trades, the immediate investor impact is limited; subsequent filings would show trading activity if any.

Equity Compliance Specialist

Disclosure clarifies voting and dispositive powers held.

The filing specifies sole voting power and sole dispositive power over the 1,617,006 shares, which clarifies control attributes tied to the reported position. The amendment emphasizes accurate public records for Section 13 reporting.

Regulatory compliance is improved by the correction; no proceeds or transaction details are disclosed here.

Key Figures

Beneficially owned shares: 1,617,006 shares Percent of class: 5.12% Shares outstanding: 31,595,562 shares

3 metrics

Beneficially owned shares 1,617,006 shares Amount reported as owned by Kristy Kyriakopoulos

Percent of class 5.12% Calculated using outstanding shares as of March 9, 2026

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

Key Terms

Schedule 13G/A, beneficially owned, sole dispositive power

3 terms

Schedule 13G/A regulatory

"Amendment No. 1 to the originally filed on September 11, 2025"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

beneficially owned financial

"Amount beneficially owned: 1,617,006"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 1,617,006"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Mistras Group, Inc.

(Name of Issuer)

Common Stock, $0.01 par value

(Title of Class of Securities)

60649T107

(CUSIP Number)

07/08/2025

(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

Kristy Kyriakopoulos

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 1,617,006.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,617,006.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,617,006.00

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)

5.12 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: This Amendment No. 1 to Schedule 13G ("Amendment No. 1") to the Schedule 13G originally filed with the United States Securities and Exchange Commission on September 11, 2025 (the "Original Schedule 13G"), relating to the issuer's common shares, is being filed solely to correct an administrative error in the Original Schedule 13G. This Amendment No. 1 corrects the number of shares reported as beneficially owned by the Reporting Person. Unless amended or supplemented below, the information in the Original Schedule 13G remains unchanged.

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: Kristy Kyriakopoulos
(b)	Address or principal business office or, if none, residence: 2 Suffolk Lane Princeton Junction, NJ 08550
(c)	Citizenship: United States of America
(d)	Title of class of securities: Common Stock, $0.01 par value
(e)	CUSIP No.:
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: 1,617,006
(b)	Percent of class: 5.12%* * 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: 1,617,006
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 1,617,006
	(iv) Shared power to dispose or to direct the disposition of: 0
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.

Kristy Kyriakopoulos

Signature:	/s/Kristy Kyriakopoulos
Name/Title:	Kristy Kyriakopoulos
Date:	03/31/2026

FAQ

What does Mistras Group (MG) Schedule 13G/A Amendment No. 1 report?

It corrects the beneficial ownership for Kristy Kyriakopoulos to 1,617,006 shares. The filing also states the outstanding share base of 31,595,562 shares as of March 9, 2026, used to calculate the 5.12% ownership percentage.

Does the amendment indicate a recent purchase or sale by Kristy Kyriakopoulos (MG)?

No. The amendment describes an administrative correction to a prior Schedule 13G/A and does not report any new acquisition or disposition. It restates previously reported details rather than announcing a transaction or change in holdings.

How is the 5.12% ownership percentage calculated in the MG filing?

The percentage is based on 1,617,006 shares divided by the issuer's stated outstanding shares of 31,595,562 as of March 9, 2026. That division yields the reported 5.12% beneficial ownership figure.

What voting and dispositive powers are reported in the MG amendment?

The filing reports sole voting power and sole dispositive power over all 1,617,006 shares. No shared voting or shared dispositive powers are listed for the reporting person in this amendment.

Will this Schedule 13G/A amendment change the company filings I should watch for MG?

This correction itself does not create additional filings, but future Form 4s or amendments would disclose new trades or changes. Monitoring subsequent Section 13 filings will show any material trading or ownership shifts by the reporting person.