ARQ · Arq, Inc.

Represents restricted stock awards ("RSAs") granted in accordance with the Issuer's 2026 Omnibus Incentive Plan, approved by stockholders on June 10, 2026. The RSAs shall vest on August 31, 2028.

Represents RSAs granted in accordance with the Issuer's long-term incentive plan under the 2026 Omnibus Incentive Plan, approved by stockholders on June 10, 2026. The RSAs shall vest in three equal installments, on each of August 1, 2027, March 23, 2028, and March 23, 2029.

Represents PSUs granted in accordance with the Issuer's long-term incentive plan under the 2026 Omnibus Incentive Plan.

Each PSU represents a contingent right to receive one share of the Issuer's common stock upon vesting of the PSU, which will occur, if at all, no later than March 15, 2029 subject to the reporting person's continuous service with the Issuer or its related entities and the achievement of certain pre-established goals to be measured as of December 31, 2028.

Represents the maximum number of PSUs that will vest, if at all, which is 200% of the target award.

Represents restricted stock awards ("RSAs") granted in accordance with the Issuer's long-term incentive plan under the 2026 Omnibus Incentive Plan, approved by stockholders on June 10, 2026. The RSAs shall vest in three equal installments, on each of August 1, 2027, March 23, 2028, and March 23, 2029.

Represents restricted stock awards ("RSAs") granted in accordance with the Issuer's long-term incentive plan under the 2026 Omnibus Incentive Plan, approved by stockholders on June 10, 2026. The RSAs shall vest in three equal installments, on each of August 1, 2027, March 23, 2028, and March 23, 2029.

Represents performance share units ("PSUs") granted in accordance with the Issuer's long-term incentive plan under the 2026 Omnibus Incentive Plan.

Each PSU represents a contingent right to receive one share of the Issuer's Common Stock upon vesting of the PSU, which will occur, if at all, no later than March 15, 2029 subject to the reporting person's continuous service with the Issuer or its related entities and the achievement of certain pre-established goals to be measured as of December 31, 2028.

Represents the maximum number of PSUs that will vest, if at all, which is 200% of the target award.

Represents performance share units ("PSUs") granted in accordance with the Issuer's long-term incentive plan under the 2026 Omnibus Incentive Plan.

Each PSU represents a contingent right to receive one share of the Issuer's Common Stock upon vesting of the PSU, which will occur, if at all, no later than March 15, 2029 subject to the reporting person's continuous service with the Issuer or its related entities and the achievement of certain pre-established goals to be measured as of December 31, 2028.

Represents the maximum number of PSUs that will vest, if at all, which is 200% of the target award.

Represents restricted stock awards ("RSAs") granted to Mr. Steinmetz as an employment inducement award. 75,000 RSAs shall vest on the second anniversary of the grant date and the remaining 175,000 RSAs shall vest on the third anniversary of the grant date.

Represents performance share units ("PSUs") granted to Mr. Steinmetz as an employment inducement award. Each PSU represents the right to receive one share of the Issuer's Common Stock upon vesting and settlement.

50,000 PSUs vest when the 30-day volume weighted average price of the Issuer's Common Stock (the "30-Day VWAP") equals $8.00 per share, 50,000 PSUs vest when the 30-Day VWAP equals $10.00 per share, and 50,000 PSUs vest when the 30-Day VWAP equals $15.00 per share, in each case, prior to the third anniversary of the date of grant.

Represents RSUs granted to Mr. Rasmus under the Issuer's 2026 Omnibus Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Common Stock upon vesting and settlement.

The RSUs vest in two equal installments on each of July 23, 2028, and July 23, 2029.

Represents RSUs granted to Mr. Rasmus under the Issuer's 2026 Omnibus Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Common Stock upon vesting and settlement.

200,000 RSUs vest when the 30-Day VWAP equals $3.00 per share; 200,000 RSUs vest when the 30-Day VWAP equals $6.00 per share; and 200,000 RSUs vest when the 30-Day VWAP equals $9.00 per share, in each case, prior to the third anniversary of the date of grant. If the applicable 30-Day VWAP threshold is achieved prior to the first anniversary of the grant date, the RSUs that have become earned upon achievement of such threshold shall not vest until the first anniversary of the grant date.

Represents restricted stock units ("RSUs") granted to Mr. Rasmus as an employment inducement award (the "Inducement Award"). Each RSU comprising the Inducement Award represents the right to receive one share of the Issuer's Common Stock upon vesting and settlement.

The two reported transactions involved an amendment of the Inducement Award, originally granted to Mr. Rasmus on July 17, 2023, to extend the expiration date of the Inducement Award from July 17, 2026, to July 17, 2029. The Inducement Award amendment may be deemed a cancellation of the original Inducement Award and grant of a replacement Inducement Award. Of the 400,000 RSUs comprising the Inducement Award, 250,000 RSUs shall vest when the 30-day volume weighted average price of the Issuer's Common Stock (the "30-Day VWAP") equals $10.00 per share and 150,000 RSUs shall vest when the 30-Day VWAP equals $15.00 per share, in each case, prior to July 17, 2029.

Represents restricted stock units ("RSUs") granted to Mr. Rasmus as an employment inducement award (the "Inducement Award"). Each RSU comprising the Inducement Award represents the right to receive one share of the Issuer's Common Stock upon vesting and settlement.

The two reported transactions involved an amendment of the Inducement Award, originally granted to Mr. Rasmus on July 17, 2023, to extend the expiration date of the Inducement Award from July 17, 2026, to July 17, 2029. The Inducement Award amendment may be deemed a cancellation of the original Inducement Award and grant of a replacement Inducement Award. Of the 400,000 RSUs comprising the Inducement Award, 250,000 RSUs shall vest when the 30-day volume weighted average price of the Issuer's Common Stock (the "30-Day VWAP") equals $10.00 per share and 150,000 RSUs shall vest when the 30-Day VWAP equals $15.00 per share, in each case, prior to July 17, 2029.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2027.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2027.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2027.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2027.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2027.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock awards. The sale was made to satisfy tax withholding obligations to be funded by a "sell to cover" transaction.

This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.2700 to $2.2822, 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.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock awards ("RSAs") on March 23, 2026.

This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.140 to $2.285, 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 reported on this row are held by Omeshorn Holdings Ltd. Richard Campbell-Breeden, a Director of the Issuer, is a director of Omeshorn Holdings Ltd. and therefore is an indirect beneficial owner of the securities reported herein.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock awards ("RSAs") on March 23, 2026.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock awards ("RSAs") on March 23, 2026.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock awards ("RSAs") on March 23, 2026.

This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1.8850 to $1.8900, 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.

This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1.925 to $1.950, 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.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of PSUs on February 27, 2026.

On February 27, 2026, the Compensation Committee of the Board of Directors of the Issuer determined that of the 30,225 performance share units ("PSUs") awarded to the reporting person on March 23, 2023 pursuant to the 2023 Long Term Incentive Plan under the Issuer's 2022 Omnibus Equity Incentive Plan, 40,286 PSUs vested based on the achievement of specific performance criteria over a three year performance period ended December 31, 2025. Each vested PSU represented the right to receive one share of the Issuer's common stock.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of PSUs on February 27, 2026.

On February 27, 2026, the Compensation Committee of the Board of Directors of the Issuer determined that of the 51,467 performance share units ("PSUs") awarded to the reporting person on March 23, 2023 pursuant to the 2023 Long Term Incentive Plan under the Issuer's 2022 Omnibus Equity Incentive Plan, 68,600 PSUs vested based on the achievement of specific performance criteria over a three year performance period ended December 31, 2025. Each vested PSU represented the right to receive one share of the Issuer's common stock.

On February 27, 2026, the Compensation Committee of the Board of Directors of the Issuer determined that of the 51,467 performance share units ("PSUs") awarded to the reporting person on March 23, 2023 pursuant to the 2023 Long Term Incentive Plan under the Issuer's 2022 Omnibus Equity Incentive Plan, 68,600 PSUs vested based on the achievement of specific performance criteria over a three year performance period ended December 31, 2025. Each vested PSU represented the right to receive one share of the Issuer's common stock.

Represents the maximum number of PSUs that were eligible to vest, if at all, which was 200% of the target award.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of PSUs on February 27, 2026.

On February 27, 2026, the Compensation Committee of the Board of Directors of the Issuer determined that of the 21,179 performance share units ("PSUs") awarded to the reporting person on March 23, 2023 pursuant to the 2023 Long Term Incentive Plan under the Issuer's 2022 Omnibus Equity Incentive Plan, 28,229 PSUs vested based on the achievement of specific performance criteria over a three year performance period ended December 31, 2025. Each vested PSU represented the right to receive one share of the Issuer's common stock.

Represents the maximum number of PSUs that were eligible to vest, which was 200% of the target award.

On February 27, 2026, the Compensation Committee of the Board of Directors of the Issuer determined that of the 30,225 performance share units ("PSUs") awarded to the reporting person on March 23, 2023 pursuant to the 2023 Long Term Incentive Plan under the Issuer's 2022 Omnibus Equity Incentive Plan, 40,286 PSUs vested based on the achievement of specific performance criteria over a three year performance period ended December 31, 2025. Each vested PSU represented the right to receive one share of the Issuer's common stock.

Represents the maximum number of PSUs that were eligible to vest, which was 200% of the target award.

On February 27, 2026, the Compensation Committee of the Board of Directors of the Issuer determined that of the 21,179 performance share units ("PSUs") awarded to the reporting person on March 23, 2023 pursuant to the 2023 Long Term Incentive Plan under the Issuer's 2022 Omnibus Equity Incentive Plan, 28,229 PSUs vested based on the achievement of specific performance criteria over a three year performance period ended December 31, 2025. Each vested PSU represented the right to receive one share of the Issuer's common stock.

This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.49 to $3.62, 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 reported on this row are held by Omeshorn Holdings Ltd. Richard Campbell-Breeden, a Director of the Issuer, is a director of Omeshorn Holdings Ltd. and therefore is an indirect beneficial owner of the securities reported herein.

This price is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.53 to $3.56. 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.

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.

Represents shares of common stock of the Issuer held by MWB Limited which were transferred to a minority owner of MWB Limited on September 25, 2025 in anticipation of the intended dissolution of the MWB Limited entity. Allard Services Limited is the majority owner of MWB Limited. Concurrently, the remaining 352,042 shares of the Issuer's common stock held by MWB Limited were transferred to Allard Services Limited and are included in the total securities beneficially owned by Allard Services Limited reported in this row.

The reported amount includes 352,042 shares, 43,034 shares and 21,908 shares of common stock that were transferred to Allard Services Limited from MWB Limited, Markham Fuels Management Limited and Stannard Limited, respectively, since the date of the last report filed by the reporting person. As of the date of this report, MWB Limited, Markham Fuels Management Limited and Stannard Limited no longer hold shares of the Issuer's common stock.

The shares reported on this row are held by Allard Services Limited. Julian McIntyre, a Director of the Issuer, controls Allard Services Limited and therefore is an indirect beneficial owner of the securities reported herein.

Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock awards ("RSAs") on September 18, 2025.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock awards. The sale was made to satisfy tax withholding obligations to be funded by a "sell to cover" transaction.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock awards. The sale was made to satisfy tax withholding obligations to be funded by a "sell to cover" transaction.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock awards. The sale was made to satisfy tax withholding obligations to be funded by a "sell to cover" transaction.

The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock awards. The sale was made to satisfy tax withholding obligations to be funded by a "sell to cover" transaction.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2026.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2026.

Represents restricted stock awards granted in exchange for the reporting owner's service as a non-employee director of the Issuer. The restricted stock awards shall vest on July 1, 2026.