Michael Mioska was named Chief Financial Officer of Birchtech Corp., succeeding Fiona Fitzmaurice, effective May 1, 2026. As of November 6, 2026, Birchtech Corp. has reported 2 leadership change filings to the SEC under Item 5.02 of Form 8-K, from May 6, 2026 to May 12, 2026, naming 2 appointments and 1 departure (Form 8-K, May 6, 2026).
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Birchtech Corp. reported changes in 2 filings among its directors and officers to the SEC on Form 8-K, Item 5.02, from 2026-05-06 to 2026-05-12. They name 3 people, with 2 appointments and 1 departure. Every row below is cited to the filing it comes from, and this page adds each new change as Birchtech Corp. files it.
Also on the record for Birchtech Corp.
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| October 5, 2026 | Stake report, Schedule 13G, by Laurence W. Lytton | 5.2% of the class | 5%+ stakes | Source |
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More on Birchtech Corp. and the records around it.
Birchtech Corp. elsewhere on the record
Companies that share a holder
- Laurence W. Lytton also filed stake reports on 28 other companies: Retension Pharmaceuticals, Inc. (Oct 2026), Rank One Computing Corp (Aug 2026), MDxHealth SA (Aug 2026)
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Timeline
| Filed | In / out | Person | Role | Effective | Source |
|---|---|---|---|---|---|
| 2026-05-12 | Reported | not named in the filing | 8-K/A, 2026-05-12 | ||
| 2026-05-06 | Out | Chief Financial Officer | 8-K, 2026-05-06 | ||
| 2026-05-06 | In | Chief Financial Officer | 2026-05-01 | 8-K, 2026-05-06 | |
| 2026-05-06 | In | Chief Operating Officer | 8-K, 2026-05-06 |
Who leads Birchtech Corp., as last reported?
For each role that changed in the filings below, the most recent change reported. A role that did not change in these filings is not listed.
- Chief Operating Officer: James Trettel, appointed (filed 2026-05-06).
- Chief Financial Officer: Fiona Fitzmaurice, departure reported (filed 2026-05-06). No successor is named in these filings.
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Reported
The arrangement has an indefinite term and is subject to the applicable notice and termination provisions.
- Pursuant to such arrangement, Mr. Mioska will be employed by Oyster HR Inc. and assigned to provide services to the Company on a full-time basis as Chief Financial Officer.
- Mr. Mioska will be paid an annual base salary of $425,000 CAD (approximately $312,000 USD).
- Mr. Mioska will be eligible to receive discretionary cash bonuses annually during the course of his employment.
Departing: Fiona Fitzmaurice, Chief Financial Officer
Item 5.02(b) - Departure of Chief Financial Officer On May 1, 2026, Fiona Fitzmaurice ceased serving as Chief Financial Officer of Birchtech Corp. (the "Company") following notice from the Company on that date.
Appointed: Michael Mioska, Chief Financial Officer, effective 2026-05-01
Item 5.02(c) - Appointment of Chief Financial Officer and Chief Operating Officer Effective May 1, 2026, the Company appointed Michael Mioska as its Chief Financial Officer.
Appointed: James Trettel, Chief Operating Officer
In addition, on May 1, 2026, the Company appointed James Trettel as its Chief Operating Officer, and in connection with his appointment, he ceased serving as Executive Vice President of Operations.
- The Company's decision was not the result of any disagreement with the Company on any matter relating to the Company's operations, policies or practices.
- Ms. Fitzmaurice served as Chief Financial Officer pursuant to an agreement dated November 1, 2023, under which she provided fractional Chief Financial Officer services to the Company.
- The Company provided notice of termination of such agreement in accordance with its terms.
- Michael Mioska, age 45, is a Chartered Professional Accountant with over 20 years of accounting, audit and financial reporting experience in a variety of industries, in both the United States and Canada.
- Prior to his appointment, Mr. Mioska was employed by DeNovo Group providing finance, financial reporting and M&A advisory-related services to a range of public companies as an independent consultant since 2021, including Birchtech Corp. since 2023.
- From 2005 to 2021, Mr. Mioska worked at a public accounting firm in Vancouver, BC providing similar finance services.
- Mr. Mioska earned a Bachelor of Arts from the University of British Columbia and a Masters of Business Administration from Laurentian University.
- He is a Chartered Professional Accountant (CPA) in Canada.
- The Company expects to enter into an arrangement with a third-party employer of record pursuant to which Mr. Mioska will be employed by such third party and assigned to provide services to the Company.
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Where this comes from
A public company must file a current report on Form 8-K with the SEC within four business days when a director leaves or is elected, or when its chief executive, chief financial, chief accounting or chief operating officer, or another named executive, departs or is appointed. That disclosure goes under Item 5.02 of the report.
Every change on this page is taken from one of those filings and quoted in the company's own words, with a link to the filing, so it can be checked at the source. Where a filing names the person, the role and the date a change takes effect, they are shown beside the quote. Where it does not, the quote stands on its own. A filing states what changed; it rarely states why, and neither does this page.