Form 8-K

8-K — Custom Truck One Source, Inc.

Accession: 0001709682-26-000034

Filed: 2026-06-11

Period: 2026-06-11

CIK: 0001709682

SIC: 7359 (SERVICES-EQUIPMENT RENTAL & LEASING, NEC)

Item: Submission of Matters to a Vote of Security Holders

Item: Financial Statements and Exhibits

Documents

8-K — ctos-20260611.htm (Primary)

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8-K

8-K (Primary)

Filename: ctos-20260611.htm · Sequence: 1

ctos-20260611

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of Earliest Event Reported): June 11, 2026

CUSTOM TRUCK ONE SOURCE, INC.

(Exact Name of Registrant as Specified in its Charter)

Delaware 001-38186 84-2531628

(State or other jurisdiction

of incorporation) (Commission

File Number) (IRS Employer

Identification No.)

7701 Independence Avenue

Kansas City, Missouri

64125

(Address of principal executive offices) (Zip Code)

(816) 241-4888

(Registrant’s telephone number, including area code)

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class Trading Symbol(s) Name of Each Exchange on Which Registered

Common Stock, $0.0001 par value CTOS New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.07. Submission of Matters to a Vote of Security Holders.

On June 11, 2026, the Company held an annual meeting of stockholders to vote on the following proposals, as described in more detail in the Company's Proxy Statement:

Proposal One: To elect three Class A directors to serve until the 2029 annual meeting of stockholders and until their successors are duly elected and qualified. In accordance with the voting results listed below, each of the nominees was elected as a Class A director.

Nominee For Withheld Broker Non-Votes

Paul Bader 178,245,358 23,142,056 9,154,365

Mark D. Ein 177,818,159 23,569,255 9,154,365

David Glatt 176,968,280 24,419,134 9,154,365

Proposal Two: To ratify the appointment of Ernst & Young LLP as the Company's independent registered public accounting firm for fiscal year ending December 31, 2026. In accordance with the voting results listed below, the appointment of Ernst & Young LLP was ratified by stockholders.

For Against Abstain

209,767,213 41,309 733,257

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No. Description

104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date:

June 11, 2026

Custom Truck One Source, Inc.

/s/ Christopher J. Eperjesy

Christopher J. Eperjesy

Chief Financial Officer

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Entity Tax Identification Number

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