Document



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

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. 11)*
Mistras Group, Inc.

(Name of Issuer)
Common Stock, $0.01 par value

(Title of Class of Securities)
60649T 107

(CUSIP Number)

December 31, 2020

(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

oRule 13d-1(b)
oRule 13d-1(c)
þRule 13d-1(d)
* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes ).



CUSIP No. 60649T 107SCHEDULE 13G
Page 2

  
1
NAMES OF REPORTING PERSONS
Sotirios J. Vahaviolos

2
 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)o
(See Instructions) (b)o

3SEC USE ONLY
4CITIZENSHIP OR PLACE OF ORGANIZATION
United States
5
SOLE VOTING POWER

NUMBER OF8,609,193 (includes 6,427 restricted stock units)
SHARES6SHARED VOTING POWER
BENEFICIALLY
OWNED BY0
EACH7SOLE DISPOSITIVE POWER
REPORTING
PERSON8,609,193 (includes 6,427 restricted stock units)
WITH8SHARED DISPOSITIVE POWER
0
9AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
8,609,193 (includes 6,427 restricted stock units)
10
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

(See Instructions) o
11
PERCENTAGE OF CLASS REPRESENTED BY AMOUNT IN ROW 9

29.4%*
12TYPE OF REPORTING PERSON (See Instructions)
IN
* This percentage calculation is based on 29,240,120 outstanding shares as of December 31, 2020, consisting of 29,233,693 shares issued and outstanding and 6,427 restricted stock units held by the reporting person.
Item 1(a). Name of Issuer:



CUSIP No. 60649T 107SCHEDULE 13G
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               Mistras Group, Inc.
     
Item 1(b). Address of Issuer’s Principal Executive Offices:
     
               195 Clarksville Road, Princeton Junction, New Jersey 08550
Item 2(a). Name of Person Filing:

              Sotirios J. Vahaviolos
     
Item 2(b). Address of Principal Business Office or, if None, Residence:
     
               195 Clarksville Road, Princeton Junction, New Jersey 08550
     
Item 2(c). Citizenship:
     
               United States
     
Item 2(d). Title of Class of Securities:
     
               Common Stock, $0.01 par value
     
Item 2(e). CUSIP Number:
     
     60649T 107

          
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:

    Not applicable

Item 4.Ownership.

    Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

     (a)         Amount beneficially owned:
     
8,609,193 (includes 6,427 restricted stock units)

     
     (b)         Percent of class:
     
           29.4% (See footnote to 11 above on Page 2)
     
     (c)         Number of shares as to which the person has:



CUSIP No. 60649T 107SCHEDULE 13G
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     (i)         Sole power to vote or to direct the vote
     
8,609,193 (includes 6,427 restricted stock units)

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

          0
     
     (iii)         Sole power to dispose or to direct the disposition of
     
8,609,193 (includes 6,427 restricted stock units)

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

         0

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

    Not Applicable.

        
Item 6.         Ownership of More than Five 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.         Certification.

              Not Applicable.
SIGNATURE



CUSIP No. 60649T 107SCHEDULE 13G
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     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.
February 8, 2021
/s/ Sotirios J. Vahaviolos