Mistras Group, Inc. has 14 Schedule 13D or 13G filings on record since 2025-07-15. 5 holders' latest filing reports 5% or more of common stock, $0.01 par value. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Aspasia Felice Vahaviolos | 19.2% | 6,105,650 | SCHEDULE 13G/A, 2026-08-13 | 2026-06-30 |
| Stephanie Athena Foglia | 19.1% | 5,532,313 | SCHEDULE 13D/A, 2026-09-21 | 2026-09-17 |
| Mill Road Capital III, L.P. | 6.1% | 1,938,316 | SCHEDULE 13D/A, 2026-09-18 | 2026-09-16 |
| Dimensional Fund Advisors LP | 5.2% | 1,623,141 | SCHEDULE 13G, 2025-07-15 | 2025-06-30 |
| Kristy Kyriakopoulos | 5.12% | 1,617,006 | SCHEDULE 13G/A, 2026-03-31 | 2025-07-08 |
Purpose of Transaction (Item 4)
Stephanie Athena Foglia
Item 4 of the Schedule 13D is hereby amended and restated in its entirety as follows: On September 17, 2026, the Issuer entered into an Agreement and Plan of Merger (the "Merger Agreement") with Athena Purchaser, LLC ("Parent") and Athena Merger Sub, Inc., a wholly owned subsidiary of Parent ("Merger Sub"). The Merger Agreement provides that, upon the terms and subject to the conditions set forth therein, Merger Sub will merge with and into the Issuer, with the Issuer surviving the merger as a wholly owned subsidiary of Parent (the "Merger"). At the effective time of the Merger (the "Effective Time"), each share of common stock, par value $0.01 per share, of the Issuer ("Common Stock") issued and outstanding immediately prior to the Effective Time (other than shares held by Parent, Merger Sub or the Issuer as treasury stock, and shares held by stockholders who properly exercise and perfect appraisal rights under Section 262 of the General Corporation Law of the State of Delaware) will be cancelled and converted into the right to receive $20.35 per share in cash, without interest and subject to any applicable withholding taxes (the "Merger Consideration"). Concurrently with the execution of the Merger Agreement, each Reporting Person entered into a voting and support agreement (each, a "Voting Agreement" and collectively, the "Voting Agreements") with Parent, pursuant to which the Reporting Persons agreed, among other things, to vote their shares of Common Stock in favor of …The first part of Item 4 of the SCHEDULE 13D/A filed 2026-09-21; the filing has the rest
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-15 | Dimensional Fund Advisors LP | 5.2% | SCHEDULE 13G |
| 2025-09-11 | Aspasia Vahaviolos | 19.4% | SCHEDULE 13G |
| 2025-09-11 | Kristy Kyriakopoulos | 5.3% | SCHEDULE 13G |
| 2025-09-11 | Stephanie Foglia | 5.1% | SCHEDULE 13G |
| 2026-03-31 | Stephanie Foglia | 21.72% | SCHEDULE 13D |
| 2026-03-31 | Aspasia Vahaviolos | 19.32% | SCHEDULE 13G |
| 2026-03-31 | Kristy Kyriakopoulos | 5.12% | SCHEDULE 13G/A |
| 2026-04-23 | Mill Road Capital III, L.P. | 5.9% | SCHEDULE 13D/A |
| 2026-06-04 | Stephanie Foglia | 19.89% | SCHEDULE 13D/A |
| 2026-06-12 | Stephanie Foglia | 18.6% | SCHEDULE 13D/A |
| 2026-08-13 | Aspasia Felice Vahaviolos | 19.2% | SCHEDULE 13G/A |
| 2026-09-14 | Stephanie Athena Foglia | 17.4% | SCHEDULE 13D/A |
| 2026-09-18 | Mill Road Capital III, L.P. | 6.1% | SCHEDULE 13D/A |
| 2026-09-21 | Stephanie Athena Foglia | 19.1% | SCHEDULE 13D/A |
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.