NRGV · Energy Vault Holdings, Inc. · Insider Trading

Represents shares sold to satisfy the reporting person's Australian tax liability on vesting of restricted stock units.

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.

Mr. Hixon is the sole trustee of the Dylan Hixon Childrens Trust FBO Casimir R. Hixon. Mr. Hixon may be deemed to have beneficial ownership of the securities held by such trust. Mr. Hixon disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein

Mr. Hixon is the sole trustee of the DHH Hixon Family Great Grandchildrens Trust FBO Soren A. Hixon. Mr. Hixon may be deemed to have beneficial ownership of the securities held by such trust. Mr. Hixon disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.

This transaction involved the purchase of shares of common stock by the reporting persons son. The reporting person disclaims beneficial ownership of the securities held by his son, and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for purposes of Section 16 or for any other purpose.

Mr. Hixon is the sole trustee of the DHH Hixon Family Great Grandchildrens Trust FBO Casimir R. Hixon. Mr. Hixon may be deemed to have beneficial ownership of the securities held by such trust. Mr. Hixon disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.

Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer 's Common Stock. The RSUs will vest as to 25% of the underlying shares on September 30, 2027, and as to the remaining of the underlying shares in 12 substantially similar quarterly installments thereafter.

Represents an award of performance restricted stock units ("PRSUs"). The PRSUs are eligible to vest based on certain share price targets commencing on the first anniversary of the vesting commencement date, subject to the applicable minimum service period. The PRSUs will vest in three tranches as follows: (i) 50,000 upon achievement of an $8.00 Share Price Target, provided the reporting person is continuously employed through the first anniversary of the vesting commencement date for a minimum of twelve months, (ii) 150,000 upon achievement of a $10.00 Share Price Target, provided the reporting person remains continuously employed through the second anniversary of the vesting commencement date for a minimum of twenty-four months, and (iii) 200,000 upon achievement of a $12.00 Share Price Target, provided the reporting person remains continuously employed through the third anniversary of the vesting commencement date for a minimum of thirty-six months.

The sale reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan.

The stock option vested as to 25% of the underlying shares on June 30, 2025, and as to the remaining of the underlying shares in 12 substantially similar quarterly installments thereafter.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units. Not a market sale.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units. Not a market sale.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units. Not a market sale.

The stock option vests in three substantially equal annual installments beginning on March 31, 2027.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest (subject to the reporting person's continued service on the Board) on June 1, 2027.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest (subject to the reporting person's continued service on the Board) on June 1, 2027.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest (subject to the reporting person's continued service on the Board) on June 1, 2027.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest (subject to the reporting person's continued service on the Board) on June 1, 2027.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest (subject to the reporting person's continued service on the Board) on June 1, 2027.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest (subject to the reporting person's continued service on the Board) on June 1, 2027.

The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted on December 19, 2025.

The stock option vested as to 25% of the underlying shares on June 30, 2025, and as to the remaining of the underlying shares in 12 substantially similar quarterly installments thereafter.

The shares are purchased in one transaction at a price given in Column 4.

Reflects a transfer of securities in a transaction exempt from reporting pursuant to Rule 16a-12.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units. Not a market sale.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units. Not a market sale.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units. Not a market sale.

The shares are purchased in one transaction at a price given in Column 4.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest with a 3-Year vesting period (subject to the Reporting Person's continued service to the Company or its subsidiaries through the applicable vesting date), with 33.2% vesting after 12 months, followed by quarterly vesting of 8.35%. Vesting commencement date is 3/31/2026.

Reflects an award of restricted stock units (RSUs). Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest with a 3-Year vesting period (subject to the Reporting Person's continued service to the Company or its subsidiaries through the applicable vesting date), with 33.2% vesting after 12 months, followed by quarterly vesting of 8.35%. Vesting commencement date is 3/31/2026.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

The shares are purchased in one transaction at a price given in Column 4.

The shares are purchased in one transaction at a price given in Column 4.

The shares are purchased in one transaction at a price given in Column 4.

The shares are purchased in one transaction at a price given in Column 4.

On April 15, 2024, the Reporting Person was granted a performance-based restricted stock unit ("PSU") award under the Energy Vault Inc.'s 2022 Equity Incentive Plan covering 600,000 Performance RSUs that will vest immediately upon achievement of the following stock performance objectives: the Company's share price achieving a daily closing trading price at or above certain price levels for 20 trading days within any 30 trading day period during the period beginning on the first anniversary of the date of grant and ending on the fourth anniversary of the date of grant: $3.50, $4.50, and $5.50 per share. Upon the achievement of each price threshold as described in this paragraph, approximately 33% of the Performance RSUs (200,000 shares) shall vest, subject to the Reporting Person's continued service. The company achieved the price threshold of $3.50 on December 31, 2025 and the price threshold of $4.50 on January 7, 2026.

On April 15, 2024, the Reporting Person was granted a performance-based restricted stock unit ("PSU") award under the Energy Vault Inc.'s 2022 Equity Incentive Plan covering 600,000 Performance RSUs that will vest immediately upon achievement of the following stock performance objectives: the Company's share price achieving a daily closing trading price at or above certain price levels for 20 trading days within any 30 trading day period during the period beginning on the first anniversary of the date of grant and ending on the fourth anniversary of the date of grant: $3.50, $4.50, and $5.50 per share. Upon the achievement of each price threshold as described in this paragraph, approximately 33% of the Performance RSUs (200,000 shares) shall vest, subject to the Reporting Person's continued service. The company achieved the price threshold of $3.50 on December 31, 2025 and the price threshold of $4.50 on January 7, 2026.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units earned on January 30, 2026.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units earned on January 30, 2026.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Securities held of record by SoftBank Vision Fund (AIV M2) L.P. ("AIV M2"). SB Investment Advisers (UK) Limited ("SBIA UK") has been appointed as alternative investment fund manager ("AIFM") and is exclusively responsible for managing AIV M2 in accordance with the Alternative Investment Fund Managers Directive and is authorized and regulated by the UK Financial Conduct Authority accordingly. As AIFM of AIV M2, SBIA UK is exclusively responsible for making all decisions related to the acquisition, structuring, financing, voting and disposal of AIV M2's investments

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $4.660 to $5.110. 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.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

Represents shares withheld by the Issuer to satisfy the reporting person's tax liability on vesting of restricted stock units.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.995 to $3. 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 purchased at each separate price within the range set forth in this footnote.