Ownership Submission

FORM 4 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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * MOOK JOSHUA T. 2. Issuer Name and Ticker or Trading Symbol Hyliion Holdings Corp. [HYLN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Technology Officer (Last) (First) (Middle) C/O HYLIION HOLDING CORP., 1202 BMC DRIVE, SUITE 100 3. Date of Earliest Transaction (Month/Day/Year) 11/14/2024 (Street) CEDAR PARK, TX 78613 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) 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 11/14/2024 C(1) 60,750 A $ 0 361,405 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Underlying Securities (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 of Derivative Security: 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

Performance Stock Incentive Units

(2)

11/14/2024

C

60,750

02/13/2025

12/31/2026

Common Stock

60,750

$ 0

101,250

D

Reporting Owners

Reporting Owner Name / Address	Relationships
Director	10% Owner	Officer	Other
MOOK JOSHUA T. C/O HYLIION HOLDING CORP. 1202 BMC DRIVE, SUITE 100 CEDAR PARK, TX 78613			Chief Technology Officer

Signatures

/s/ Joshua T. Mook	11/18/2024
**Signature of Reporting Person	Date

Explanation of Responses:

*	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).
(1)	The underlying market conditions for vesting of this portion of performance stock incentive units ("PSU Award") were satisfied on November 13, 2024, and subsequently approved by the Compensation Committee on November 14, 2024. Half of the vested PSUs will be issued on November 14, 2025 with the remainder to be issued on December 31, 2026.
(2)	30% of these PSU Awards vested upon the achievment of the underlying closing stock price threshold of a minimum of $2.50 per share over a 30-trading-day average.

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