X0508 4 2025-11-10 0 0001515156 Arq, Inc. ARQ 0001555130 Rasmus Robert E. C/O ARQ, INC. 8051 E MAPLEWOOD AVE STE 210 GREENWOOD VILLAGE CO 80111 1 1 0 0 Chief Executive Officer 0 Common Stock 2025-11-10 4 P 0 50000 3.7918 A 70718 I By RER Investments LLC Common Stock 527779 I By RER Legacy Investments II LLC. Common Stock 480782 D This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.73 to $3.86, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this Form 4. The shares of Common Stock reported on this row are held by RER Investments LLC ("RER Investments"). Mr. Rasmus, the Chief Executive Officer and a Director of the Issuer, is the ultimate control person of RER Investments, and an indirect beneficial owner of these shares. Mr. Rasmus disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein. The shares of Common Stock reported on this row are held by RER Legacy Investments II LLC ("RER Legacy"). Mr. Rasmus, the Chief Executive Officer and a Director of the Issuer, is the ultimate control person of RER Legacy, and an indirect beneficial owner of these shares. Mr. Rasmus disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein. /s/ Robert E. Rasmus 2025-11-12