Custom Truck director exercises RSUs, gets new grant

Custom Truck One Source, Inc. director Mary M. Jackson reported routine equity compensation activity.

Rhea-AI Filing Summary

Custom Truck One Source, Inc. director Mary M. Jackson reported routine equity compensation activity. She received a grant of 19,225 restricted stock units, each representing one share of common stock, which will vest on March 31, 2027. Previously granted restricted stock units totaling 26,859 vested in full on March 31, 2026 and were exercised, delivering 26,859 shares of common stock. Following these transactions, she directly holds 82,032 shares of common stock.

Insider Trade Summary

26,859 shares exercised/converted

Exercise 3 txns

Insider Jackson Mary M.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Restricted Stock Unit	19,225	$0.00	$0.00
Exercise	Restricted Stock Unit	26,859	$0.00	$0.00
Exercise	Common Stock	26,859	$0.00	$0.00

Holdings After Transaction: Restricted Stock Unit — 19,225 contracts (Direct); Common Stock — 82,032 shares (Direct)

Footnotes (3)

1. F1. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock.
2. F2. The restricted stock units vested in full on March 31, 2026.
3. F3. The restricted stock units will vest on March 31, 2027 and have no expiration date.

Key Figures

RSUs exercised: 26,859 units New RSU grant: 19,225 units Common shares after transactions: 82,032 shares +1 more

4 metrics

RSUs exercised 26,859 units Restricted stock units vested and converted on March 31, 2026

New RSU grant 19,225 units Restricted stock units granted and scheduled to vest on March 31, 2027

Common shares after transactions 82,032 shares Directly held by Mary M. Jackson following reported Form 4 activity

Underlying common per RSU 1 share per unit Each restricted stock unit represents one share of common stock

Key Terms

Restricted Stock Unit, derivative security, vested in full, contingent right

4 terms

Restricted Stock Unit financial

"Each restricted stock unit represents a contingent right to receive one share"

A restricted stock unit is a promise from a company to give an employee shares of stock after certain conditions are met, like staying with the company for a set amount of time. It’s like earning a bonus that turns into company stock once you’ve proven your commitment, making it a way to motivate and reward employees.

derivative security financial

"transaction_code_description": "Exercise or conversion of derivative security"

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

vested in full financial

"The restricted stock units vested in full on March 31, 2026"

contingent right financial

"represents a contingent right to receive one share of the Issuer's common stock"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did CTOS director Mary M. Jackson report?

Mary M. Jackson reported routine equity compensation. She exercised 26,859 vested restricted stock units into 26,859 shares of Custom Truck One Source common stock and received a new grant of 19,225 restricted stock units, with all holdings reported as direct ownership.

How many Custom Truck One Source shares does Mary M. Jackson now hold?

After the reported transactions, Mary M. Jackson directly holds 82,032 shares of Custom Truck One Source common stock. This reflects the conversion of 26,859 vested restricted stock units into shares and adds to her existing equity position with the company.

What new restricted stock units were granted to CTOS director Mary M. Jackson?

Mary M. Jackson received a grant of 19,225 restricted stock units, each representing one share of Custom Truck One Source common stock. These units are part of her equity compensation and increase her contingent right to receive additional common shares upon vesting.

When do Mary M. Jackson’s Custom Truck One Source RSUs vest?

One tranche of Mary M. Jackson’s restricted stock units vested in full on March 31, 2026, leading to the delivery of 26,859 common shares. A separate grant of 19,225 restricted stock units will vest on March 31, 2027, according to the reported footnotes.

What does the RSU exercise on March 31, 2026 mean for CTOS stock ownership?

On March 31, 2026, 26,859 restricted stock units vested and were exercised, converting into 26,859 shares of Custom Truck One Source common stock. This shifted value from derivative awards into direct share ownership, increasing Mary M. Jackson’s directly held common stock.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

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Accepted by SEC EDGAR 04/02/2026 - 04:30 PM EDT Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Jackson Mary M.

(Last) (First) (Middle)

7701 INDEPENDENCE AVE

(Street)

KANSAS CITY MISSOURI 64125

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Custom Truck One Source, Inc. [ CTOS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/31/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/31/2026		M		26,859	A	$0(1)	82,032	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Unit	(1)	03/31/2026		M			26,859	(2)	(2)	Common Stock	26,859	$0	0	D
Restricted Stock Unit	(1)	04/01/2026		A		19,225		(3)	(3)	Common Stock	19,225	$0	19,225	D

Explanation of Responses:

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

2. The restricted stock units vested in full on March 31, 2026.

3. The restricted stock units will vest on March 31, 2027 and have no expiration date.

	By: /s/ Paul M. Jolas, Attorney-in-fact	04/02/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)