ORN · Orion Group Holdings Inc

The Issuer withheld 2,325 shares to satisfy tax withholding obligations in connection with the vesting of 9,546 restricted shares granted to the Reporting Person on June 23, 2025, resulting in the Reporting Person retaining 7,221 shares from such award.

The restricted shares are subject to cliff vesting on the date of the Company's 2027 annual general meeting, expected to occur in May 2027, contingent upon the reporting person's continued service through the vesting date.

The restricted shares are subject to cliff vesting on the date of the Company's 2027 annual general meeting, expected to occur in May 2027, contingent upon the reporting person's continued service through the vesting date.

The restricted shares are subject to cliff vesting on the date of the Company's 2027 annual general meeting, expected to occur in May 2027, contingent upon the reporting person's continued service through the vesting date.

The restricted shares are subject to cliff vesting on the date of the Company's 2027 annual general meeting, expected to occur in May 2027, contingent upon the reporting person's continued service through the vesting date.

The restricted shares are subject to cliff vesting on the date of the Company's 2027 annual general meeting, expected to occur in May 2027, contingent upon the reporting person's continued service through the vesting date.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $14.60 per share to $14.70 per share, 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 sold at each separate price within the ranges set forth in this footnote.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $14.55 per share to $14.73 per share, 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 sold at each separate price within the ranges set forth in this footnote.

The Issuer withheld 2,884 shares to satisfy tax withholding obligations in connection with the vesting of 11,842 restricted shares granted to the Reporting Person on March 20, 2025, resulting in the Reporting Person retaining 8,958 shares from such award.

The Issuer withheld 15,377 shares to satisfy tax withholding obligations in connection with the vesting of 39,077 restricted shares granted to the Reporting Person on March 20, 2025, resulting in the Reporting Person retaining 23,700 shares from such award.

Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the March 20, 2026 vesting of a portion of the March 20, 2024 restricted stock grant.

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $11.93 per share to $12.385 per share, 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 sold at each separate price within the ranges set forth in this footnote.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $11.75 per share to $11.96 per share, 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 sold at each separate price within the ranges set forth in this footnote.

This grant of restricted shares is scheduled to vest ratably on April 1, 2027, April 1, 2028 and April 1, 2029.

Reflects a reduction of shares withheld to cover taxes payable by the reporting person due to the March 3, 2026, vesting and payout of performance stock units granted in 2023.

This grant of restricted shares is scheduled to vest ratably on April 1, 2027, April 1, 2028 and April 1, 2029.

This grant of restricted shares is scheduled to vest ratably on April 1, 2027, April 1, 2028 and April 1, 2029.

The reported transaction reflects the payout of 241,636 performance stock units ("PSUs") granted to Mr. Boone in 2023, which were subject to a three-year cliff vesting period and performance conditions based 25% on absolute stock price performance and 75% on absolute ROIC performance. On March 3, 2026, the Compensation Committee determined that the applicable performance conditions were achieved at target, resulting in full payout and vesting of the 241,636 PSUs in the form of shares of common stock.

Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the November 28, 2025, vesting of a portion of the November 27,2023 restricted stock grant.

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the August 15, 2025 vesting of a portion of the August 15, 2022 restricted stock grant.

This grant of restricted stock vests in three equal annual installments beginning on June 23, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $8.64 per share to $8.71 per share, 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 sold at each separate price within the ranges set forth in this footnote.

This grant of restricted stock vests in three equal annual installments beginning on April 1, 2026.

This grant of restricted stock vests in three equal annual installments beginning on April 1, 2026.

This grant of restricted stock vests in three equal annual installments beginning on April 1, 2026.

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

These shares were acquired under the Orion Group Holdings, Inc. Employee Stock Purchase Plan in transactions that were exempt under Rule 16b-3(c).

Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the November 27, 2024, vesting of a portion of the November 27,2023 restricted stock grant.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $5.97 to $6.14, 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 ranges set forth in this footnote.

Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the August 15, 2024 vesting of a portion of the August 15, 2022 restricted stock grant.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $6.749 to $6.850, 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 ranges set forth in this footnote.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $6.785 to $6.80, 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 ranges set forth in this footnote.