MTX: Material agreement · New financial obligation

Item 1.01. Entry into a Material Definitive Agreement Senior Notes due 2032 On October 13, 2026, Minerals Technologies Inc. (the “Company”) completed its previously announced offering of $400,000,000 aggregate principal amount of its 7.500% Senior Notes due 2032 (the “Notes”). The Company intends to use the net proceeds of its offering of the Notes, together with cash on hand, (i) to redeem all of the outstanding 5.000% senior notes due 2028 and (ii) to pay transaction fees and expenses related to this offering and the Amendment (as defined below). The terms of the Notes are governed by an indenture dated as of October 13, 2026 (the “Indenture”), among the Company, the subsidiary guarantors party thereto and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”). The Notes bear interest at a rate of 7.500% per annum payable semi-annually in arrears on January 15 and July 15 of each year, beginning on January 15, 2027. The Notes are guaranteed by the Company’s wholly owned domestic restricted subsidiaries that are obligors or guarantors under its senior secured credit facilities or certain other indebtedness. At any time and from time to time prior to January 15, 2029, the Company may redeem some or all of the Notes for cash at a redemption price equal to 100% of their principal amount, plus the “make-whole” premium described in the Indenture and accrued and unpaid interest, if any, to, but excluding, the applicable redemption date. Beginning on January 15, 2029, the Company may redeem some or all of the Notes at any time and from time to time at the applicable redemption prices listed in the Indenture, plus accrued and unpaid interest, if any, to, but excluding, the applicable redemption date. In addition, at any time and from time to time prior to Ja