Other Events On August 18, 2026, the Company issued a press release announcing the closing of the Notes Offering and its entry into the Amended and Restated Credit Agreement. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Entry into a Material Definitive Agreement Notes Offering On August 18, 2026, Griffon Corporation (the “Company”) completed its previously announced notes offering (the “Notes Offering”) of $800 million aggregate principal amount of 6.25% senior notes due 2034 (the “Notes”). The Notes were sold in a private placement pursuant to a purchase agreement, dated August 10, 2026, among the Company, the guarantors named therein (the “Guarantors”) and BofA Securities, Inc., as representative of the se…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant The information provided in

Regulation FD Disclosure. On August 10, 2026, Griffon Corporation (the “Company”) issued a press release announcing the commencement of an offering through a private placement, subject to market and other conditions, of $800 million in aggregate principal amount of senior notes due 2034 (the “Offering”). A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The information in Exhibit 99.1 is being furnished pursuant to

Other Events. Griffon Corporation ("Griffon" or “the Company”) is filing this Current Report on Form 8-K (this “Form 8-K”), including Exhibit 99.1, solely to recast certain financial information and related disclosures included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2025 originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on November 19, 2025 (the “2025 Form 10-K”) to provide retrospective discontinued operations presentat…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

Other Events On July 31, 2026, we repaid the remaining balance of $285 million of Term Loan B outstanding under our credit agreement with proceeds received in connection with the Joint Venture and revolver borrowings under the credit agreement. 3

Completion of Acquisition or Disposition of Assets. On July 31, 2026, Griffon closed the sale of its AMES Australasia business to form the Joint Venture. Griffon HoldCo holds a 49% indirect equity interest in the Joint Venture following the consummation of the transactions contemplated by the SSA. The remaining 51% ownership of the Joint Venture is held by an investment group led and controlled by Simon Hupfeld, the Executive Chairman of the business. Under the terms of the SSA, Griffon HoldC…

In connection with the closing of the transactions contemplated by the SSA, on July 31, 2026, Griffon HoldCo, Buyer, and HupCo Holdings Pty Ltd entered into a side letter to the SSA (the “ Side Letter ”), pursuant to which, among other things, the parties agreed: (i) to novate (a) Griffon HoldCo’s equity interest in TopCo, (b) its rights and obligations under the shareholders’ agreement relating to the Joint Venture, and (c) its rights and obligations under the PIK Note, in each case to other…

Regulation FD Disclosure. On August 3, 2026, Griffon issued a press release announcing the closing of the Joint Venture. A copy of Griffon’s press release is attached hereto as Exhibit 99.1.

Entry into a Material Definitive Agreement. Closing of Joint Venture; Amended and Restated Master Transaction Agreement On June 9, 2026, Griffon Corporation (“ Griffon ”) closed the joint venture (“ JV ”) of its AMES United States and Canada businesses with Venanpri Tools, the global professional and consumer tool provider majority owned by ONCAP Management Partners, L. P. (“ ONCAP ”), a subsidiary of Onex Corporation. The closing was pursuant to an amended and restated master transaction agr…

Regulation FD Disclosure. On June 10, 2026, Griffon issued a press release announcing the closing of the transactions contemplated by the A&R MTA. A copy of Griffon’s press release is attached hereto as Exhibit 99.3. On June 10, 2026, Griffon and ONCAP issued a joint press release announcing the closing of the transactions contemplated by the A&R MTA. A copy of the joint press release is attached hereto as Exhibit 99.4. On June 8, 2026, Griffon issued a press release announcing it has entered…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 3 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 3 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of Registrant. The information contained in

Entry into a Material Definitive Agreement. On June 26, 2023, Griffon Corporation entered into a second amendment (the “Amendment”) to its fifth amended and restated credit agreement (as amended, the “Credit Agreement”), by and among Bank of America, N.A., as administrative agent, and the other lenders party to the Credit Agreement. The Amendment ● Refinances and replaces the existing senior secured term loans outstanding under the Credit Agreement with new term loans (the “Term Loan B”) on s…

and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. 3 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of…

The filing discloses shareholder approval of an equity incentive plan amendment, which is a compensatory arrangement rather than a change in management personnel.