Mistras Group (MG)Aspasia Felice Vahaviolos disclosed a 19.1% stake in MG and may seek to influence the company 19.1%

19.1%

Stake

6.08M

Shares owned

Stake as of

Sep 17, 2026

Filed

Oct 7, 2026

The story around this disclosure

Every dated public record OQRO holds about the company from 60 days before to 120 days after, oldest first. It shows what was going on; none of it is a stated reason for the trade.

1. Aug 10, 2026Company filing · Form 8-K · ResultsReported its results
2. Sep 17, 2026Company filing · Form 8-K · Material agreement, Executive changeChanged a top executive or board member, and signed an important agreement (and 2 more items)“On September 17, 2026, in connection with the contemplated Merger, the Compensation Committee of the Board (the “Compensation Committee”) approved cash retention bonus awards for certain key employees of the Company, including the following named executive officers: Natalia Shuman, President and Chief Executive Officer ($750,000); Edward J. Prajzner, Senior Executive Vice President and Chief Financial Officer…”

What came next

1. Sep 28, 2026Federal contract · $28K obligatedDepartment of Health and Human Services awarded Mistras Group, Inc.: $28K obligated to date
2. Oct 7, 20265% stakeAspasia Felice Vahaviolos filed an activist stake (13D) of 19.1%

How to read SEC Schedule 13D

A Schedule 13D and a Schedule 13G both disclose beneficial ownership of more than 5% of a US company's voting shares. A 13D is the long form, filed by holders who may seek to influence or control the company, and it must state what they intend to do. A 13G is the short form, open only to passive holders and to certain institutions holding in the ordinary course of business, and it asks no question about intent.

Full guide: Schedule 13D vs Schedule 13G: what is the difference?

What else is on file for Mistras Group

For Mistras Group, OQRO holds 1 fund holdings report (13F) and 1 federal contract award dated in the last 90 days.

These are records OQRO holds, counted by their date, not a measure of how much trading took place. Routine paperwork such as option exercises and tax withholding is left out. Everything for the company is on its MG page.

How this filing works

• Schedule 13D vs 13G

Other disclosures at Mistras Group

• USAspending.gov award recordSep 28, 2026
• USAspending.gov award recordApr 20, 2026
• SEC Form 4Sep 25, 2025
• SEC Form 4Jun 6, 2025
• SEC Form 4Mar 20, 2025
• SEC Form 4Mar 20, 2025

Everything OQRO holds on this company is on its MG page.