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Mistras Group, Inc.

MG
Exchange
NYSE
Industry
Services-Engineering Services
SEC CIK
0001436126

No open-market purchases or sales by Mistras Group, Inc. insiders were filed in the last 90 days; 137 institutions reported holding it in 13F filings for Q2 2026, worth $336.7M in total; no superinvestor holds it.

Holders of 5% or more of MG

Holders whose latest Schedule 13D or 13G filing reports 5% or more of Mistras Group, Inc., largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of MG
HolderLatest formStakeChangeFirst filedLatest filingFiling
Foglia Stephanie Athena13D21.72%6.86M shares+16.62 ppfrom 5.10%Sep 11, 20252 filingsMar 31, 2026SEC
Vahaviolos Aspasia Felice13G19.32%6.11M shares−0.08 ppfrom 19.40%Sep 11, 20252 filingsMar 31, 2026SEC
Mill Road Capital III, L.P.13D/A5.70%1.76M shares–Mar 10, 20251 filingMar 10, 2025SEC
Dimensional Fund Advisors LP13G5.20%1.62M sharesNewJul 15, 20251 filingJul 15, 2025SEC
Kyriakopoulos Kristy Vahaviolos13G/A5.12%1.62M shares−0.18 ppfrom 5.30%Sep 11, 20252 filingsMar 31, 2026SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

8 Schedule 13D and 13G filings on Mistras Group, Inc., newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on MG
Filed (ET)FilerFormStakeChangeEvent dateFiling
Mar 31, 20264:25 PM ETKyriakopoulos Kristy Vahaviolos13G/A5.12%1.62M shares−0.18 ppfrom 5.30%Jul 8, 2025SEC
Mar 31, 20264:17 PM ETVahaviolos Aspasia Felice13G19.32%6.11M shares−0.08 ppfrom 19.40%Dec 31, 2025SEC
Mar 31, 20264:12 PM ETFoglia Stephanie Athenaand 1 other13D21.72%6.86M shares+16.62 ppfrom 5.10%Dec 31, 2025SEC
Sep 11, 20254:52 PM ETFoglia Stephanie Athena13G5.10%1.60M sharesNewJul 8, 2025SEC
Sep 11, 20254:50 PM ETKyriakopoulos Kristy Vahaviolos13G5.30%1.67M sharesNewJul 8, 2025SEC
Sep 11, 20254:50 PM ETVahaviolos Aspasia Felice13G19.40%6.11M sharesNewMay 23, 2025SEC
Jul 15, 20254:03 PM ETDimensional Fund Advisors LP13G5.20%1.62M sharesNewJun 30, 2025SEC
Mar 10, 20258:08 PM ETMill Road Capital III, L.P.and 2 others13D/A5.70%1.76M shares–Mar 6, 2025SEC

Form 144: proposed insider sales

Notices from officers, directors and other affiliates planning to sell Mistras Group, Inc. shares.

No Form 144 notices for Mistras Group, Inc. are on file.