AMPL Amplitude Inc

United States

Securities and Exchange Commission

Washington, D.C. 20549

Schedule 13G

(Rule 13d-102)

Information to be Included in Statements Filed Pursuant

to § 240.13d-1(b), (c) and (d) and Amendments Thereto Filed

Pursuant to § 240.13d-2

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)*

Amplitude, Inc.

(Name of Issuer)

Class A Common Stock, par value $0.00001

(Title of Class of Securities)

03213A104

(CUSIP Number)

November 1, 2024

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Amplitude, Inc. (the “Issuer”).

201 Third Street, Suite 200, San Francisco, California 94103

This statement is filed on behalf of Curtis Liu (the “Reporting Person”).

The business address of the Reporting Person is c/o Amplitude, Inc., 201 Third Street, Suite 200, San Francisco, California 94103

The Reporting Person is a citizen of the United States.

Class A Common stock, par value $0.00001 per share (“Class A Common Stock”).

03213A104

Not applicable.

The ownership information below represents beneficial ownership of Class A Common Stock of the Issuer as of November 1, 2024, based upon 102,606,023 shares of Class A Common Stock, which includes 94,590,532 shares of Class A Common Stock of the Issuer outstanding as of November 1, 2024, as disclosed in the Issuer’s Form 10-Q, filed with the SEC on November 7, 2024. The Class A Common Stock amount used herein assumes the conversion of the Class B common stock, par value $0.00001 per share (“Class B Common Stock”) of the Issuer held by the Reporting Person into shares of Class A Common Stock on a one-to-one basis, and the exercise of stock options held by the Reporting Person that are exercisable within 60 days of November 1, 2024.

The Reporting Person is deemed to be the beneficial owner of 8,094,719 shares of Class A Common Stock, which includes: (i) 79,228 shares of Class A Common Stock held in one or more trusts over which the Reporting Person exercises voting and investment discretion; (ii) 7,382,208 shares of Class A Common Stock issuable upon conversion of 7,382,208 shares of Class B Common Stock held in one or more trusts over which the Reporting Person exercises voting and investment discretion; and (iii) 633,283 shares of Class A Common Stock issuable upon the exercise of stock options that are exercisable within 60 days of November 1, 2024.

(i) Sole power to vote or to direct the vote: 8,094,719

(ii) Shared power to vote or direct the vote: 0

(iii) Sole power to dispose or to direct the disposition of: 8,094,719

(iv) Shared power to dispose or to direct the disposition of: 0

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: November 13, 2024