MTUS

Each phantom share is the equivalent of one Issuer common share.

Phantom shares are payable in cash and/or common shares upon termination of the Reporting Person's service on the Board of Directors, as elected by the Reporting Person at the time he elected to defer compensation under the Metallus Inc. Director Deferred Compensation Plan.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Each phantom share is the equivalent of one Issuer common share.

Phantom shares are payable in cash and/or common shares upon termination of the Reporting Person's service on the Board of Directors, as elected by the Reporting Person at the time he elected to defer compensation under the Metallus Inc. Director Deferred Compensation Plan.

The reported transaction is an award of restricted stock units which will vest in full on March 2, 2029, subject to the terms of the grant agreement.

The reported transaction is an award of restricted stock units which will vest in full on March 2, 2029, subject to the terms of the grant agreement.

The reported transaction is an award of restricted stock units which will vest in full on March 2, 2029, subject to the terms of the grant agreement.

The reported transaction is an award of restricted stock units which will vest in full on March 2, 2029, subject to the terms of the grant agreement.

The reported transaction is an award of restricted stock units which will vest in full on March 2, 2029, subject to the terms of the grant agreement.

The reported transaction is an award of restricted stock units which will vest in full on March 2, 2029, subject to the terms of the grant agreement.

Price reported is the weighted average sale price for shares sold by the reporting owner on February 4, 2026. Shares were sold at a variety of prices ranging from $21.00 to $21.54.

Price reported is the weighted average sale price for shares sold by the reporting owner on February 4, 2026. Shares were sold at a variety of prices ranging from $21.00 to $21.54.

Vested in four equal annual installments beginning March 1, 2020.

Price reported is the weighted average sale price for shares sold by the reporting owner on February 3, 2026. Shares were sold at a variety of prices ranging from $21.00 to $21.17.

Vested in four equal annual installments beginning March 1, 2020.

Price reported is the weighted average sale price for shares sold by the reporting owner on February 3, 2026. Shares were sold at a variety of prices ranging from $21.00 to $21.17.

Vested in four equal annual installments beginning March 1, 2020.

Price reported is the weighted average sale price for shares sold by the reporting owner on January 15, 2026. Shares were sold at prices ranging from $21.00 to $21.01.

Price reported is the weighted average sale price for shares sold by the reporting owner on January 15, 2026. Shares were sold at prices ranging from $21.00 to $21.01.

Vested in four equal annual installments beginning March 1, 2020.

Price reported is the weighted average sale price for shares sold by the reporting owner on January 14, 2026. Shares were sold at a variety of prices ranging from $20.00 to $20.14.