MNTS · Momentus Inc.

This first amendment to the Form 4 filed by the Reporting Person on 05/21/2026 indicates a correction to the amount of securities acquired.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of RSUs, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of RSUs, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unite (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of RSUs, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

This first amendment to the Form 4 filed by the Reporting Person on 05/21/2026 indicates a correction to the amount of derivative securities acquired.

Represents a grant of RSUs, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of May 18, 2027 or the day of the 2027 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of May 18, 2027 or the day of the 2027 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of May 18, 2027 or the day of the 2027 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of May 18, 2027 or the day of the 2027 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unite (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of May 18, 2027 or the day of the 2027 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of May 18, 2027 or the day of the 2027 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

This transaction was executed in multiple trades at prices ranging from $5.275 to $5.6099. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

The reporting person was previously reported as a beneficial owner of securities held by SRC-NI Holdings, LLC. The number of shares reported in Column 5 as direct ownership is greater than previously reported due to a distribution of shares by SRC-NI Holdings, LLC to its investors.

Each Restricted Stock Unit represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in four equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit represents a contingent right to receive one share of Momentus Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSU Award will vest 6.25% of the total number of RSUs on November 20, 2021. 18.75% of the total number of RSUs will vest upon the first anniversary starting on August 20, 2022 and as to 25% of the total number of RSUs on each of the second, third and fourth anniversaries, subject to Executive's continued Employment through each such vesting date.

These shares were withheld by the Issuer in order to satisfy certain tax withholding obligations in connection with the issuance of vested restricted stock units.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

This transaction is being reported late due to an administrative error.

Represents a grant of Restricted Stock Units, which vest in four equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of June 30, 2026 or the day before the 2026 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of June 30, 2026 or the day before the 2026 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of June 30, 2026 or the day before the 2026 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of June 30, 2026 or the day before the 2026 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of June 30, 2026 or the day before the 2026 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

The RSUs will vest in full on the earlier to occur of June 30, 2026 or the day before the 2026 Annual Meeting, subject to the Reporting Person's continued service as a member of the Board of Directors through such vesting date.

The Reporting Person elected to defer receipt of 16,294 shares of Class A Common Stock granted to the Reporting Person. Each share of Deferred RSUs is the economic equivalent of one share of MNTS Class A Common Stock.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in three equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

Each Restricted Stock Unit (RSU) represents a contingent right to receive one share of Momentus, Inc. Class A Common Stock.

Represents a grant of Restricted Stock Units, which vest in four equal annual installments from Vesting Commencement Date, subject to Executive's continued Employment through each such vesting date.

These shares were withheld by the Issuer in order to satisfy certain tax withholding obligations in connection with the issuance of vested restricted stock units.

Reflects a 1-for-14 reverse stock split that was effected by Momentus Inc. on December 5, 2024.

Reflects a 1-for-14 reverse stock split that was effected by Momentus Inc. on December 5, 2024.