X0508 4 2024-04-01 0001001385 NORTHWEST PIPE CO NWPX 0001228503 MONTROSS SCOTT J 201 NE PARK PLAZA DRIVE SUITE 100 VANCOUVER WA 98684 1 President & CEO 0 Common Stock 2024-04-01 4 M 0 8095 A 124854 D Common Stock 2024-04-01 4 F 0 3232 35.16 D 121622 D Common Stock 2024-04-01 4 M 0 8744 A 130366 D Common Stock 2024-04-01 4 F 0 3491 35.16 D 126875 D Common Stock 2024-04-01 4 M 0 7744 A 134619 D Common Stock 2024-04-01 4 F 0 3092 35.16 D 131527 D Performance Shares 2024-04-01 4 M 0 6581 D Common Stock 8095 64977 D Performance Shares 2024-04-01 4 M 0 7949 D Common Stock 8744 57028 D Performance Shares 2024-04-01 4 M 0 8604 D Common Stock 7744 48424 D Restricted Stock Common Stock 16141 D Represents shares acquired pursuant to the vesting of Performance Shares. Represents shares withheld by the issuer for payment of taxes incurred upon vesting event consistent with company policy. Performance Shares vest in an amount ranging from 0-200% to the extent such Performance Shares are earned. Performance Shares are earned based on Northwest Pipe Company's total EBITDA margin over the measurement period. Performance Shares vest in installments as follows: 1/3 March 31, 2022, 1/3 on March 31, 2023 and 1/3 on April 1, 2024. Performance Shares vest in installments as follows: 1/3 on March 31, 2023, 1/3 on April 1, 2024 and 1/3 on March 31, 2025. Performance Shares vest in installments as follows: 1/3 on April 1, 2024, 1/3 on March 31, 2025 and 1/3 on March 31, 2026. Each Restricted Stock Unit represents a contingent right to receive one share of Northwest Pipe Company common stock. The Restricted Stock Units vest in installments in January of 2025, 2026 and 2027. /s/ Megan Kendrick 2024-04-03