[Form 4/A] Hyliion Holdings Corp. Amended Insider Trading Activity

Rhea-AI Filing Summary

Hyliion Holdings Corp. insider Thomas J. Healy, the chief executive officer, director and 10% owner of HYLN, filed an amended Form 4 to correct a prior report for August 25, 2025. The earlier filing had shown shares of common stock withheld to cover taxes, but the company states this was due to an administrative error by its third-party service provider and that no shares were actually withheld on that date. Following the correction, Healy is shown as directly owning 35,396,887 shares of Hyliion common stock.

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

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

1. Name and Address of Reporting Person^*

Healy Thomas J.

(Last) (First) (Middle)

C/O HYLIION HOLDING CORP.

1202 BMC DRIVE, SUITE 100

(Street)

CEDAR PARK TX 78613

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Hyliion Holdings Corp. [ HYLN ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
08/25/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)
08/25/2025

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

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

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	08/25/2025		F(1)		0	D	$0	35,396,887	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

Explanation of Responses:

1. This Amended Form 4 has been filed to delete a reference to shares withheld to satisfy taxes on the reporting person's Form 4 filed with the SEC on August 25, 2025. The shares were initially reported as withheld as a result of an administrative error by the issuer's third party service provider. No shares were withheld on August 25, 2025 and Column 5 of Table 1 has been revised accordingly.

Remarks:

	/s/ Thomas J. Healy	11/18/2025
	** 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.

FAQ

What did Hyliion (HYLN) disclose in this amended Form 4/A?

The amended Form 4/A corrects a prior filing to state that no Hyliion common shares were withheld for taxes on August 25, 2025, revising the reported holdings accordingly.

How many Hyliion (HYLN) shares does Thomas J. Healy now report owning?

After the correction, Thomas J. Healy reports direct ownership of 35,396,887 shares of Hyliion Holdings Corp. common stock.

Why was the original Hyliion (HYLN) Form 4 filing amended?

The original Form 4 was amended because it referenced shares withheld to satisfy taxes, which the company attributes to an administrative error by a third-party service provider. The amendment clarifies that no shares were withheld on that date.

What was the transaction date referenced in the Hyliion Form 4/A amendment?

The amended Form 4/A relates to activity on August 25, 2025, which is listed as the earliest transaction date in the filing.

What is Thomas J. Healy’s relationship to Hyliion Holdings Corp. (HYLN)?

Thomas J. Healy is identified as a director, chief executive officer, and 10% owner of Hyliion Holdings Corp.

Does this Hyliion Form 4/A reflect any new share sales or purchases?

No new acquisitions or disposals are reported; the amendment updates prior information to show that no shares were withheld on the referenced date and confirms the 35,396,887 shares held directly.