Form 8-K

8-K — FLEXIBLE SOLUTIONS INTERNATIONAL INC

Accession: 0001493152-26-027673

Filed: 2026-06-08

Period: 2026-06-03

CIK: 0001069394

SIC: 2890 (MISCELLANEOUS CHEMICAL PRODUCTS)

Item: Changes in Registrant's Certifying Accountant

Item: Financial Statements and Exhibits

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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): June 3, 2026

FLEXIBLE

SOLUTIONS INTERNATIONAL INC.

(Exact

name of Registrant as specified in its charter)

Alberta,

Canada

Alberta

001-31540

71-1630889

(State

or other jurisdiction

of incorporation)

(Commission

File No.)

(Employer

Identification No.)

6001

54 Ave.

Taber,

Alberta, Canada T1G 1X4

(Address

of principal executive offices, including Zip Code)

Registrant’s

telephone number, including area code: (250) 477-9969

N/A

(Former

name or former address if changed since last report)

Check

the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligations 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-14(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities

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

Title

of each class

Trading

Symbol

Name

of exchange on which registered

Common

Stock

FSI

NYSE

American

Indicate

by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§203.405

of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§204.12b-2 of this chapter.

Emerging

growth company ☐

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.

(a)

Resignation of Independent Registered Public Accounting Firm.

June 3, 2026, we were notified that Assure CPA, LLC (“Assure”), which served as the independent registered public accounting

firm of Flexible Solutions International, Inc. (the “Company”), merged into Sadler, Gibb & Associates, LLC. (“Sadler

Gibb”) pursuant to an asset purchase agreement. As a result of the transaction, Assure ceased operations as a public accounting

firm and resigned as the Company’s independent registered public accounting firm.

The

resignation of Assure and the engagement of Sadler Gibb described in paragraph (b) below were approved by the Audit Committee of the

Company’s Board of Directors on June 5, 2026.

Assure’s

audit reports on the Company’s consolidated financial statements for the fiscal years ended December 31, 2025 and 2024 did not

contain an adverse opinion or a disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope, or accounting

principles.

During

the fiscal years ended December 31, 2025 and 2024 and the subsequent interim period through June 3, 2026, there were (i) no disagreements

(within the meaning of Item 304(a)(1)(iv) of Regulation S-K and the related instructions) with Assure on any matter of accounting principles

or practices, financial statement disclosure, or auditing scope or procedures which, if not resolved to Assure’s satisfaction,

would have caused Assure to make reference to the matter in its reports, and (ii) no “reportable events” within the meaning

of Item 304(a)(1)(v) of Regulation S-K.

The

Company has provided Assure with a copy of this Current Report on Form 8-K and has requested that Assure furnish a letter addressed to

the Securities and Exchange Commission stating whether it agrees with the statements made by the Company herein. A copy of Assure’s

letter, dated June 5, 2026, is filed as Exhibit 16.1 to this report.

(b)

Engagement of New Independent Registered Public Accounting Firm.

June 5, 2026, the Company’s Audit Committee approved the engagement of Sadler Gibb as the Company’s independent registered

public accounting firm for the fiscal year ending December 31, 2026.

During

the fiscal years ended December 31, 2025 and 2024 and the subsequent interim period through June 5, 2026, neither the Company nor anyone

on its behalf consulted with Sadler Gibb regarding (i) the application of accounting principles to any specified transaction, either

completed or proposed, or the type of audit opinion that might be rendered on the Company’s financial statements, and no written

report or oral advice was provided to the Company that Sadler Gibb 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 either the subject of a disagreement

(as defined in Item 304(a)(1)(iv) and the related instructions) or a reportable event (as described in Item 304(a)(1)(v)).

Item

9.01. Financial Statements and Exhibits.

16.1

Letter

from Assure CPA, LLC dated June 5, 2026.

104

Cover

Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

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 hereunto duly authorized.

Date:

June 8, 2026

FLEXIBLE

SOLUTIONS INTERNATIONAL INC.

By:

/s/

Daniel B. O’Brien

Daniel

B. O’Brien, President and Chief Executive Officer

EX-16.1

Filename: ex16-1.htm · Sequence: 2

EXHIBIT

16.1

June

5, 2026

Securities

and Exchange Commission

100

F Street, N.E.

Washington,

D.C. 20549

Ladies

and Gentlemen:

have read the statements made by Flexible Solutions International, Inc. relating to the event described under Item 4.01 of its Current

Report on Form 8-K dated June 5, 2026, and we agree with the statements concerning our firm contained therein.

Very

truly yours,

/s/

Assure CPA, LLC

Assure

CPA, LLC

Spokane,

Washington

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