Energy Vault (NRGV) director sale tied to Australian tax bill

Rhea-AI Filing Summary

Energy Vault Holdings, Inc. (NRGV) director Stephanie Unwin reported selling 115,000 shares of common stock on 2026-08-26 in an open-market or private transaction at a weighted average price of $3.7129 per share. The filing states the shares were sold to satisfy her Australian tax liability arising from the vesting of restricted stock units. Following this sale, she directly holds 182,245 shares of NRGV common stock.

Insider Trade Summary

Net Seller: 115,000 shares

Net Sell 1 txn

Insider Unwin Stephanie

Role Director

Sold 115,000 shs ($427K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	115,000	$3.7129	$427K

Holdings After Transaction: Common Stock — 182,245 shares (Direct)

Footnotes (2)

1. F1. Represents shares sold to satisfy the reporting person's Australian tax liability on vesting of restricted stock units.
2. F2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.615 to $3.905. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Key Figures

Shares sold: 115,000 shares of common stock Weighted average sale price: $3.7129 per share Sale price range: $3.615 to $3.905 per share +2 more

5 metrics

Shares sold 115,000 shares of common stock Sale transaction dated 2026-08-26 coded “S”

Weighted average sale price $3.7129 per share Weighted average price for multiple trades in the sale

Sale price range $3.615 to $3.905 per share Range of prices for the individual trades included in the sale

Shares held after transaction 182,245 shares Direct holdings of common stock following the sale

Net shares sold 115,000 shares transactionSummary netBuySellShares reported as net-sell

Key Terms

weighted average price, restricted stock units, Australian tax liability, open market or private transaction

4 terms

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

restricted stock units financial

"tax liability on vesting of restricted stock units."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Australian tax liability financial

"shares sold to satisfy the reporting person's Australian tax liability"

open market or private transaction financial

"transaction code description Sale in open market or private transaction"

FAQ

What insider transaction did NRGV director Stephanie Unwin report on this Form 4?

She reported a sale of 115,000 shares of Energy Vault Holdings, Inc. (NRGV) common stock on 2026-08-26 in a transaction coded “S” (sale in open market or private transaction).

At what price were the NRGV shares sold by Stephanie Unwin?

The shares were sold at a weighted average price of $3.7129 per share. The filing explains they were sold in multiple trades at prices ranging from $3.615 to $3.905.

Why did Stephanie Unwin sell 115,000 shares of NRGV stock?

The filing states the 115,000 shares were sold to satisfy her Australian tax liability that arose upon the vesting of restricted stock units.

How many NRGV shares does Stephanie Unwin hold after this transaction?

After the reported sale, Stephanie Unwin directly holds 182,245 shares of Energy Vault Holdings, Inc. common stock.

Was the reported NRGV stock sale made under a Rule 10b5-1 trading plan?

The Rule 10b5-1 checkbox in the filing is not checked, and the footnotes do not describe a trading plan, so the sale is not identified as being made under a Rule 10b5-1 plan.

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

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Available on EDGAR 08/28/2026 - 05:08 PM Accepted by SEC EDGAR 08/28/2026 - 05:08 PM 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^*

Unwin Stephanie

(Last) (First) (Middle)

4165 EAST THOUSAND OAKS BLVD,

SUITE 100

(Street)

WESTLAKE VILLAGE CALIFORNIA 91362

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Energy Vault Holdings, Inc. [ NRGV ]

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)
08/26/2026

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	08/26/2026		S		115,000(1)	D	$3.7129(2)	182,245	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. Represents shares sold to satisfy the reporting person's Australian tax liability on vesting of restricted stock units.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.615 to $3.905. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Remarks:

	/s/ Amy Blakeway, Chief Legal Officer	08/28/2026
	** 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)