X0609 4 2026-10-05 0001598428 Metallus Inc. MTUS 0001232579 SYRVALIN KRISTINE C false 1835 DUEBER AVE. SW CANTON OH 44706 false true false false EVP General Counsel true Common Shares 2026-10-05 4 S false 5000 21.12 D 101078 D Common Shares 5018 I by 401(k) plan Price reported is the weighted average sale price for shares sold by the reporting owner on October 5, 2026. Shares were sold at a variety of prices ranging from $21.00 to $21.34. The reporting person adopted a written plan for the sale of the Company's common shares intended to satisfy the affirmative defense conditions of Exchange Act Rule 10b5-1(c) on May 19, 2026. All transactions reported herein were made pursuant to that plan. /s/ Kristine C. Syrvalin 2026-10-05