X0508 4/A 2024-02-24 2024-02-27 0000041719 Glatfelter Corp GLT 0001943784 Fahnemann Thomas C/O GLATFELTER CORPORATION 4350 CONGRESS STREET, SUITE 600 CHARLOTTE NC 28209 1 1 CEO 0 Common Stock, Par Value $.01 2024-02-24 4 M 0 80000 0 A 93000 D Common Stock, Par Value $.01 2024-02-24 4 F 0 22974 2.01 D 70026 D Restricted Stock Units 0 2024-02-24 4 M 0 80000 0 D 2024-02-24 2026-02-24 Common Stock, Par Value $.01 80000 160000 D These shares are being withheld to satisfy tax obligations. Because the payout occurred on a Saturday, February 24, 2024, the value of the shares was determined using the closing price of the previous business day Friday, February 23, 2024. This RSU grant vesting on 2/24/2024 is the first one-third vesting of the SET RSU 2/24/2023 Grant. The final one-third vests, and all restrictions lapse, on 2/24/2026. This Form 4 amendment is being filed to report all unvested Restricted Stock Units and Performance Share Awards held by the reporting person that were previously reported as directly owned securities on Table I on Table II as derivative securities. This presentation is consistent with the reporting of unvested Restricted Stock Units on other Form 4s filed by the reporting person. Accordingly, the total amount of securities beneficially owned as reported in Table I, Column 5 now excludes 240,000 shares underlying unvested Restricted Stock Units and 360,000 shares underlying Performance Share Awards that were previously reported on Table I. /s/ Jill L. Urey, Attorney-in-fact 2024-03-04