EXHIBIT 99.1 Custom Truck One Source, Inc. Reports First Quarter 2024 and Updates Full-Year Guidance KANSAS CITY, Mo, May 2, 2024 – (BUSINESS WIRE) – Custom Truck One Source, Inc. (NYSE: CTOS), a leading provider of specialty equipment to the electric utility, telecom, rail, forestry, waste management and other infrastructure- related end markets, today reported financial results for its three months ended March 31, 2024. CTOS First-Quarter Highlights • Total revenue of $411.3 million, a decrease of$40.9 m ...