[8-K] QUANTUM CORP /DE/ Reports Material Event

Rhea-AI Filing Summary

Quantum Corporation disclosed that its prior auditor, Grant Thornton, issued audit reports for the fiscal years ended March 31, 2025 and March 31, 2024 without an adverse or qualified opinion but included an explanatory paragraph about the company’s ability to continue as a going concern. Grant Thornton reported no disagreements with management but noted material weaknesses in the company’s internal control over financial reporting related to the controls environment, revenue recognition, manufacturing inventory, and warrants agreements, as described in Item 9A.

The Audit Committee completed a competitive selection and, on September 30, 2025, chose CohnReznick LLP to serve as the independent registered public accounting firm for the fiscal year ending March 31, 2026, contingent on completion of standard client acceptance procedures. Grant Thornton provided a letter dated October 6, 2025 and the company authorized Grant Thornton to respond fully to successor-auditor inquiries about the disclosed reportable events.

Positive

• No audit qualification from Grant Thornton for FY2025 and FY2024 reports
• No disagreements reported between the company and Grant Thornton on accounting or auditing matters
• Audit Committee completed a competitive process and selected CohnReznick LLP as successor auditor

Negative

• Explanatory going-concern paragraph included in Grant Thornton’s audit reports for FY2025 and FY2024
• Material weaknesses disclosed in internal control over financial reporting for controls environment, revenue recognition, manufacturing inventory, and warrants agreements

Insights

Audit Committee Advisor

Auditor change follows disclosure of control weaknesses and a going-concern paragraph.

The selection of CohnReznick LLP as successor auditor for the fiscal year ending March 31, 2026 formalizes a governance response after Grant Thornton identified material weaknesses in internal control across revenue, inventory, warrants, and the controls environment. The company has completed a competitive process and authorized full responsiveness to successor-auditor inquiries, which aids continuity.

Risks remain around remediation timelines for the disclosed weaknesses; investors should expect potential follow-up disclosures in the company’s next periodic filings through the upcoming fiscal year.

Financial Reporting Analyst

Going-concern explanatory paragraph and control issues are the primary near-term reporting risks.

Grant Thornton’s reports did not include a qualified opinion but did include an explanatory paragraph concerning the company’s ability to continue as a going concern, which highlights material uncertainty affecting financial statements for fiscal years ended March 31, 2025 and March 31, 2024. The identified control weaknesses relate directly to revenue recognition, manufacturing inventory, warrants, and the broader controls environment.

Concrete items to monitor include remediation progress disclosed in subsequent periodic reports and any adjustments to audit scope when CohnReznick completes client acceptance and begins interim procedures in FY2026.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 30, 2025

Quantum Corporation

(Exact name of registrant as specified in its charter)

Delaware

001-13449

94-2665054

(State or other jurisdiction of incorporation or organization)

(Commission File No.)

(I.R.S. Employer Identification No.)

10770 E. Briarwood Avenue

Centennial,

CO

80112

(Address of Principal Executive Offices)

(Zip Code)

(408)			944-4000
Registrant's telephone number, including area code

N/A

(Former name, former address and former fiscal year, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol

Name of each exchange on which registered

Common Stock, $0.01 par value per share

QMCO

Nasdaq Global Market

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 4.01 Changes in Registrant's Certifying Accountant.

Dismissal of Independent Registered Public Accounting Firm

The Audit Committee (the “Audit Committee”) of the Board of Directors of Quantum Corporation (the “Company”) conducted a competitive process to determine the Company’s independent registered public accounting firm for the fiscal year ending March 31, 2026. As a result of this process and following careful deliberation, on September 30, 2025, the Audit Committee dismissed Grant Thornton LLP (“Grant Thornton”) as the Company's independent registered public accounting firm, effective as of that same date.

Grant Thornton’s reports on the Company’s consolidated financial statements as of and for the fiscal years ended March 31, 2025 and 2024 did not contain any adverse opinion or disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope, or accounting principles, other than the explanatory paragraph regarding the Company’s ability to continue as a going concern.

During the Company’s fiscal years ended March 31, 2025 and 2024 and the subsequent interim period through September 30, 2025, there were no “disagreements” (as defined in Item 304(a)(1)(iv) of Regulation S-K and related instructions thereto) between the Company and Grant Thornton on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which disagreements, if not resolved to the satisfaction of Grant Thornton, would have caused Grant Thornton to make reference to the subject matter of the disagreement in connection with its report.

Additionally, during the fiscal years ended March 31, 2025 and 2024 and subsequent interim period through September 30, 2025, there have been no “reportable events” (as defined in Item 304(a)(1)(v) of Regulation S-K and related instructions thereto), except for material weaknesses in the Company's internal control over financial reporting related to controls environment, revenue recognition, manufacturing inventory, and warrants agreements as disclosed in Item 9A, Controls and Procedures of the Company Annual Report on Form 10-K for the years ended March 31, 2025 and 2024. The Audit Committee discussed the subject matter of each of these reportable events with Grant Thornton, and the Company authorized Grant Thornton to respond fully to the inquiries of the successor auditor concerning the subject matter of each of these reportable events.

In accordance with Item 304(a)(3) of Regulation S-K, the Company provided Grant Thornton with a copy of the disclosures it is making in this Current Report on Form 8-K and requested Grant Thornton furnish the Company with a letter addressed to the Securities and Exchange Commission stating whether Grant Thornton agrees with the statements made by the Company herein and, if not, stating the respects in which it does not agree. A copy of Grant Thornton’s letter, dated October 6, 2025, is attached as Exhibit 16.1 to this Current Report on Form 8-K.

Appointment of Independent Registered Public Accounting Firm

As described above, the Audit Committee recently completed a competitive process to select an audit firm to serve as the Company’s independent registered public accounting firm for the fiscal year ending March 31, 2026, and related interim periods. On September 30, 2025, the Company, at the recommendation of the Audit Committee, made the decision to select CohnReznick LLP (“CohnReznick”) as auditors for the Company for the fiscal year ending March 31, 2026, contingent upon the execution of an engagement letter following completion of CohnReznick’s standard client acceptance procedures.

During the fiscal years ended March 31, 2025 and 2024, and the subsequent interim period through the date of this Current Report on Form 8-K, neither the Company, nor anyone acting on its behalf, consulted CohnReznick regarding either (i) the application of accounting principles to a specified transaction, either completed or proposed, or the type of audit opinion that might be rendered with respect to the Company’s consolidated financial statements, and neither a written report nor oral advice was provided to the Company by CohnReznick that CohnReznick concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing or financial reporting issue; or (ii) any matter that was the subject of a disagreement within the meaning of Item 304(a)(1)(iv) of Regulation S-K or a reportable event within the meaning of Item 304(a)(1)(v) of Regulation S-K.

Item 9.01     Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.						Description
16.1						Letter from Grant Thornton LLP dated October 6, 2025.
104						Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Quantum Corporation

(Registrant)

October 6, 2025

/s/ Laura A. Nash

(Date)

Laura A. Nash

Chief Accounting Officer

FAQ

What did Grant Thornton report for Quantum Corp (QMCO)?

Grant Thornton issued audit reports for fiscal years ended March 31, 2025 and March 31, 2024 with no adverse or qualified opinion but included an explanatory paragraph about the company’s ability to continue as a going concern and noted material weaknesses in internal control.

Did Quantum (QMCO) and Grant Thornton disagree on accounting matters?

No. The company disclosed there were no disagreements with Grant Thornton during the relevant periods.

Who is the new auditor for Quantum Corp (QMCO) and when was it selected?

The Audit Committee selected CohnReznick LLP on September 30, 2025 to serve as the independent registered public accounting firm for the fiscal year ending March 31, 2026, contingent on standard client acceptance procedures.

Are there any follow-up audit correspondence items attached?

Yes. A letter from Grant Thornton dated October 6, 2025 is attached as Exhibit 16.1 addressing whether it agrees with the company’s disclosures.

What internal control areas were identified as material weaknesses?

Material weaknesses were disclosed in four areas: the controls environment, revenue recognition, manufacturing inventory, and warrants agreements.