X0609 4 2026-04-30 0001598428 Metallus Inc. MTUS 0001806395 Miller Melissa M false 1835 DUEBER AVE SW CANTON OH 44706 true false false false false Common Shares 2026-04-30 4 A false 7090 0 A 22165 D The reported transaction is an award of restricted stock units which will vest in full on April 30, 2027, subject to the terms of the grant agreement. /s/ Kristine C. Syrvalin, as Attorney-in-Fact 2026-04-30