Custom Truck One Source, Inc.
US ˙ NYSE ˙ US23204X1037

SecurityCTOS / Custom Truck One Source, Inc.
InstitutionBoston Partners
Latest Disclosed Ownership2,016,406 shares
Latest Disclosed Value $ 13,247,944
Boston Partners reports 46.85% decrease in ownership of CTOS / Custom Truck One Source, Inc.

On May 11, 2026 - Boston Partners filed a 13F-HR form disclosing ownership of 2,016,406 shares of Custom Truck One Source, Inc. (US:CTOS) valued at $13,247,787 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 3,793,597 shares of Custom Truck One Source, Inc.. This represents a change in shares of -46.85% during the quarter. The current value of the position is $19,821,271 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-11 2026-03-31 13F CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 2,016,406 -1,777,191 -46.85 13,248 -39.38 0.0059
2026-02-13 2025-12-31 13F CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 3,793,597 -1,681,710 -30.71 21,855 -37.83 0.0226
2025-11-13 2025-09-30 13F CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 5,475,307 42,232 0.78 35,150 30.92 0.0361
2025-08-12 2025-06-30 13F/A-1 CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 5,433,075 2,264,366 71.46 26,849 100.85 0.0298
2025-08-07 2025-06-30 13F CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 3,789,629 620,920 18,731 0.0086
2025-05-13 2025-03-31 13F CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 3,168,709 -627,715 -16.53 13,369 -26.82 0.0162
2025-02-11 2024-12-31 13F CUSTOM TRUCK ONE SOURCE COM CL A 23204X103 3,796,424 3,796,424 18,268 0.0222
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.