On December 6, 2021, John-Paul Munfa notified the Board of Directors of Custom Truck One Source, Inc. of his decision to resign from the Board and the Compensation Committee of the Board, effective December 6, 2021. Mr. Munfa's resignation is related to the recent reduction in ownership of the company's common stock by investment funds affiliated with Blackstone and is not the result of any disagreement between Mr. Munfa and the company or its management on any matter relating to the company's operations, policies or practices. The Board intends to fill the vacancy created by Mr. Munfa's resignation.