Mistras : Notice of 2024 Annual Shareholders Meeting and Proxy Statement.

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2024

Proxy Statement

MISTRAS GROUP, INC.

195 Clarksville Road, Princeton Junction, New Jersey 08550

Dear Mistras Shareholder:

April 4, 2024

I am pleased to invite you to attend the 2024 Annual Shareholders Meeting of Mistras Group, Inc. The annual meeting will be held on Tuesday, May 14, 2024, at 11:00 a.m., Eastern Time. The annual meeting will be conducted completely virtual, via a live webcast. You will be able to attend and participate in our annual meeting by visiting www.virtualshareholdermeeting.com/MG2024, where you will be able to listen to the annual meeting live, vote your shares and submit questions. There will be no physical meeting location.

At the annual meeting, you and our other shareholders will be asked to vote on the following:

• To elect seven directors to our Board of Directors;
• To ratify the appointment by the Audit Committee of the Board of Directors of PricewaterhouseCoopers LLP as the independent registered public accounting firm of Mistras Group, Inc. for the year ending December 31, 2024;
• To approve of the Mistras Group, Inc. Amended and Restated 2016 Long-Term Incentive Plan, including the numbers of shares authorized to be issued;
• To approve, on an advisory basis, the compensation of Mistras Group, Inc.'s named executive officers;
• Conduct any other business which properly comes before the meeting.

You are entitled to participate in the virtual meeting if you were a shareholder as of the close of business on March 18, 2024, the record date, or hold a legal proxy for the annual meeting provided by your bank, broker, or nominee. To participate in the annual meeting webcast at www.virtualshareholdermeeting.com/MG2024, you must enter the control number found on your proxy card, voting instruction form or notice you receive. You may vote online during the annual meeting by following the instructions available on the annual meeting website during the annual meeting. Whether or not you plan to attend the annual meeting online, we urge you to vote and submit your proxy in advance of the annual meeting by one of the methods described in the proxy materials for the annual meeting.

Sincerely,

Manuel N. Stamatakis

Chairman of the Board and Interim President and

Chief Executive Officer

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195 Clarksville Road, Princeton Junction, New Jersey 08550

Notice of Annual Meeting

April 4, 2024

The 2024 Annual Shareholders Meeting of Mistras Group, Inc. will be held on Tuesday, May 14, 2024 at 11:00 a.m., Eastern Time. The meeting will be held exclusively via webcast at www.virtualshareholdermeeting.com/MG2024. There will be no physical location of the meeting and you will only be able to attend the annual meeting via the webcast. The details of the meeting are as follows:

MEETING DETAILS
Time and Date	Location	Record Date
May 14, 2024	Webcast at	March 18, 2024
Tuesday at 11:00 a.m.	www.virtualshareholdermeeting.com/MG2024
Eastern Time

ITEMS OF BUSINESS:

• Election of seven directors, constituting the entire Board of Directors.

• To ratify the appointment by the Audit Committee of the Board of Directors of PricewaterhouseCoopers LLP as the independent registered public accounting firm of Mistras Group, Inc. for the year ending December 31, 2024.

• To approve the Mistras Group, Inc. Amended and Restated 2016 Long-Term Incentive Plan, including the number of shares authorized to be issued.

• To approve, on an advisory basis, the compensation of Mistras Group, Inc.'s named executive officers.

Who can vote: Holders of Mistras Group, Inc. common stock as of the close of business on March 18, 2024 are entitled to vote at the meeting and any adjournment or postponement of the meeting.

Attending the Meeting: Shareholders as of the close of business on March 18, 2024, or their duly appointed proxies, may attend the meeting online. To attend the 2024 annual meeting, go to www.virtualshareholdermeeting.com/MG2024, then enter the control number found on your proxy card, voting instruction form or notice you receive. You may vote during the meeting by following the instructions available on the meeting website during the meeting.

Voting by proxy: Please submit your proxy and/or voting instructions as described in the accompanying proxy statement or other proxy materials you receive promptly so that a quorum may be represented at the meeting.

By order of the Board of Directors

MICHAEL C. KEEFE

Executive Vice President,

General Counsel and Secretary

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS.

This Proxy Statement and the Mistras Group, Inc. 2023 Annual Report are available electronically on the Internet at

www.proxyvote.com and on the Company's website at http://investors.mistrasgroup.com/financial-information.

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Table of Contents

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Proxy Solicitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Internet Availability of Proxy Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Voting Recommendation of the Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Shareholders Entitled to Vote, Quorum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Votes Needed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 How to Vote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Changing Your Vote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Effect of Not Casting Your Vote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Attending the Meeting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Tabulating the Votes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Voting Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Corporate Governance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Board of Directors and Director Independence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Committees of the Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Board Leadership Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Lead Director . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Code of Ethics and Code of Conduct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Nomination of Directors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Director Resignation Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Stock Ownership Guidelines and Incentive Compensation Recoupment Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Insider Trading Compliance Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Other Key Governance Matters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Director Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Compensation Committee Interlocks and Insider Participation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Certain Relationships, Proceedings and Related Person Transactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Stock Ownership and Section 16 Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Stock Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Section 16(a) Beneficial Ownership Reporting Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Proposals Requiring Shareholder Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Item 1: Election of Directors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Item 2: Ratification of Appointment of Independent Registered Public Accounting Firm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Audit Committee Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Fees of Our Independent Registered Public Accounting Firm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Item 3: Approval of the Mistras Group, Inc. Amended and Restated 2016 Long-Term Incentive Plan Including the Number of Shares Authorized to be Issued . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Item 4: Advisory Vote on Executive Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Compensation Committee Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Compensation Discussion and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Executive Compensation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Summary Compensation Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Grants of Plan-Based Awards in 2023 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Outstanding Equity Awards at December 31, 2023 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Option Exercises and Stock Vested in 2023 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Pension Benefits and Non-Qualified Deferred Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Pay Ratio of CEO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Pay versus Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Potential Payments upon Termination of Employment or Change of Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Employment Agreements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Shareholder Proposals and Other Matters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Exhibit A: Mistras Group, Inc. 2016 Long - Term Incentive Plan Amended and Restated as of March 27, 2024. . . . . . . . . 56 Exhibit A-1: Amended and Restated Plan in Exhibit A with Changes to Existing Plan Highlighted . . . . . . . . . . . . . . . . . . 68

Exhibit B: Reconciliation of Non-GAAP Financial Measurements Used for Determining Incentive Compensation

to GAAP Financial Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

PROXY STATEMENT

General Information

We are providing these proxy materials in connection with the solicitation by our Board of Directors of proxies to be voted at our 2024 annual meeting of shareholders (''2024 Annual Meeting'') and at any adjournment or postponement of the 2024 Annual Meeting. You are invited to attend the 2024 Annual Meeting, which will take place on May 14, 2024, beginning at 11:00 a.m., Eastern Time, via a webcast over the Internet at www.virtualshareholdermeeting.com/MG2024.

The terms ''Mistras,'' the ''Company,'' ''we,'' ''our'' and ''us'' mean Mistras Group, Inc. and the term ''Board'' means our Board of Directors, unless the context indicates otherwise. We are incorporated in the State of Delaware, and our common stock trades on the New York Stock Exchange (''NYSE'') under the symbol ''MG.'' Our fiscal year ends December 31.

PROXY SOLICITATION

The accompanying proxy is being solicited by our Board. The notice of annual meeting and this proxy statement (''Proxy Statement'') and proxy card or voting instructions are first being distributed to shareholders on or about April 4, 2024. In addition to this solicitation, employees of the Company may solicit proxies by telephone. All costs of the solicitation of proxies will be borne by the Company. On the proxy card or voting instruction included in the materials, a shareholder of record (that is, a shareholder who holds the shares in his, her or its own name with our transfer agent, Equiniti Trust Company, LLC) may substitute the name of another person in place of those persons presently named as proxies. To vote, a substitute proxy must present adequate identification to the Corporate Secretary or Inspector of Election for the 2024 Annual Meeting before the voting occurs.

At the 2024 Annual Meeting, the proxies appointed by the Board (the persons named in the proxy card or voting instructions) will vote your shares as you instruct. If you complete and submit your proxy without indicating how you would like to vote your shares, your proxy will be voted as the Board recommends.

INTERNET AVAILABILITY OF PROXY MATERIALS

We are using the Internet as our primary means of furnishing proxy materials to shareholders as permitted by the rules of the Securities and Exchange Commission (''SEC''). Consequently, most shareholders will not receive paper copies of our proxy materials. We will instead send shareholders a Notice of Internet Availability of Proxy Materials with instructions for accessing the proxy materials, including our Proxy Statement and annual report, and voting via the Internet. The Notice of Internet Availability of Proxy Materials also provides information on how shareholders may obtain paper copies of our proxy materials if they so choose and how to attend the 2024 Annual Meeting via the Internet. This makes the proxy distribution process more efficient, less costly and helps conserve natural resources. If you previously elected to receive our proxy materials electronically, these materials will continue to be sent electronically unless you change your election.

VOTING RECOMMENDATION OF THE BOARD

The Board recommends that shareholders vote:

• FOR each of the seven nominees of the Board of Directors (Item 1);
• FOR the ratification of the appointment by the Audit Committee of the Board of Directors of PricewaterhouseCoopers LLP as our independent registered public accounting firm of Mistras Group, Inc for the year ending December 31, 2024 (Item 2);
• FOR the approval of the Mistras Group, Inc. Amended and Restated 2016 Long-Term Incentive Plan, including the number of shares authorized to be issued (Item 3); and
• FOR the approval, on an advisory basis, of the compensation of Mistras Group, Inc.'s named executive officers (Item 4).

Mistras Group, Inc.

1

2024 Proxy Statement

SHAREHOLDERS ENTITLED TO VOTE, QUORUM

Shareholders of record of our common stock at the close of business on March 18, 2024 are entitled to notice of and to vote at the 2024 Annual Meeting and any adjournments or postponements of the meeting. Each share entitles its owner to one vote.

The holders of a majority of the shares entitled to vote at the 2024 Annual Meeting must be present or represented by proxy in order to constitute a quorum for all matters to come before the 2024 Annual Meeting. Both abstentions and broker non-votes are counted for the purpose of determining the presence of a quorum. On the record date, we had 30,641,064 shares outstanding.

VOTES NEEDED

The following chart sets forth the proposals to be considered at the 2024 Annual Meeting, the voting choices for each proposal, the votes needed to elect directors and for each other agenda item to pass, and the manner in which votes will be counted.

			EFFECT OF	EFFECT OF BROKER
AGENDA ITEM	VOTING OPTIONS	VOTES NEEDED	ABSTENTIONS	NON-VOTES
	For all nominees or	Plurality, meaning the seven
1 Election of Directors	nominees receiving the most		No effect. No broker
withhold with respect	No effect
votes for their election will be	discretion to vote.
	any or all nominees.	elected.

			Majority of the shares present
2	Ratification of	For, against, or abstain.	or represented at the meeting

Counted as vote. Brokers have Same effect as vote

Appointment of Auditors	and entitled to vote on the
	matter.

against.

discretion to vote.

Approval of Mistras		Majority of the shares present
Group, Inc. Amended		Counted as vote.
	or represented at the meeting	No effect. No broker
3 and Restated 2016	For, against, or abstain.	Same effect as vote
and entitled to vote on the	discretion to vote.
Long-Term Incentive		matter.	against.
Plan

	Advisory Vote on the		Majority of the shares present
4	compensation of Mistras	For, against, or abstain.	or represented at the meeting

Counted as vote. No effect. No broker Same effect as vote

Group, Inc.'s named	and entitled to vote on the
executive officers	matter.

against.

discretion to vote.

For Item 1, Election of Directors, as set forth in the Director Resignation Policy described on page 9 each director has agreed that if he or she receives more ''Withheld'' votes than ''For'' votes, the director will tender his or her resignation for consideration by the Corporate Governance Committee and the independent members of the Board.

HOW TO VOTE

Vote by Internet

You may vote by proxy via the Internet by following the instructions provided on the enclosed Proxy Card

Vote by Mail	Vote Online at the Meeting
You may vote by completing,	You can vote at the meeting at
signing, dating and returning	www.virtualshareholdermeeting.com/
your proxy card in the	MG2024
pre-addressed,postage-paid
envelope provided.

Shares held in your name as the shareholder of record may be voted by you online at the 2024 Annual Meeting. Shares held beneficially in street name may be voted by you online at the 2024 Annual Meeting only if you obtain a legal proxy from the bank, broker, trustee or nominee that holds your shares giving you the right to vote the shares. Even if you plan to attend the 2024 Annual Meeting online, we recommend that you also submit your proxy or voting instructions as described below so that your vote will be counted if you later decide not to attend the meeting online.

You have the option of voting your shares over the Internet, by telephone or completing and returning a proxy card or voting instruction card. Voting over the Internet or telephone authorizes the named proxies to vote your shares as you direct. If you receive paper copies of our proxy materials and/or a proxy card or voting instruction card, you can also vote by marking, signing,

Mistras Group, Inc.

2

2024 Proxy Statement