Custom Truck One Source, Inc. - Director's Dealing 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Custom Truck One Source, Inc. (CTOS)
CIK: 0001709682
Period of Report: 2025-04-01

Reporting Person: JOLAS PAUL M (EVP, Gen. Counsel & Secretary)

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-04-01	Common Stock	M	33750	—	Acquired	47679	Direct
2025-04-01	Common Stock	F	13960	$4.20	Disposed	33719	Direct

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-04-01	Restricted Stock Unit	$	M	16875	Disposed		Common Stock (16875)	Direct
2025-04-01	Restricted Stock Unit	$	M	16875	Disposed		Common Stock (16875)	Direct

F1: Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock.

F2: Shares withheld to satisfy tax obligations arising out of vesting of the Reporting Person's restricted stock units.

F3: The restricted stock units vest in four equal annual installments beginning on April 1, 2024.

F4: The restricted stock units vest in four equal annual installments beginning on April 1, 2025.