Sec Form 3 Filing - SC US (TTGP), LTD. @ Amplitude, Inc. - 2021-09-21

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person SC US (TTGP), LTD. 2. Issuer Name and Ticker or Trading Symbol Amplitude, Inc. [ AMPL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 2800 SAND HILL ROAD, SUITE 101 3. Date of Earliest Transaction (MM/DD/YY) 09/21/2021 (Street) MENLO PARK, CA94025 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Class B Common Stock ( 1 ) ( 1 ) ( 1 ) Class A Common Stock 2,554,932 I Sequoia Capital Global Growth Fund III - Endurance Partners, L.P. ( 2 ) ( 3 ) Class B Common Stock ( 1 ) ( 1 ) ( 1 ) Class A Common Stock 5,330,200 I Sequoia Capital U.S. Growth Fund VIII, L.P. ( 2 ) ( 3 ) Class B Common Stock ( 1 ) ( 1 ) ( 1 ) Class A Common Stock 418,401 I Sequoia Grove II, LLC ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SC US (TTGP), LTD. 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X SC U.S. Growth VIII Management, L.P. 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X Sequoia Capital U.S. Growth Fund VIII, L.P. 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X SCGGF III - Endurance Partners Management, L.P. 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X Sequoia Capital Global Growth Fund III - Endurance Partners, L.P. 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X LEONE DOUGLAS M 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X BOTHA ROELOF 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X Sequoia Grove Manager, LLC 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X Sequoia Grove II, LLC 2800 SAND HILL ROAD, SUITE 101 MENLO PARK, CA94025 X Signatures By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Director of SC US (TTGP), Ltd. 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Director of SC US (TTGP), Ltd., the General Partner of SC U.S. Growth VIII Management, L.P. 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Director of SC US (TTGP), Ltd., the General Partner of SC U.S. Growth VIII Management, L.P., the General Partner of Sequoia Capital U.S. Growth Fund VIII, L.P. 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Director of SC US (TTGP), Ltd., the General Partner of SCGGF III - Endurance Partners Management, L.P. 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Director of SC US (TTGP), Ltd., the General Partner of SCGGF III - Endurance Partners Management, L., the General Partner of Sequoia Capital Global Growth Fund III - Endurance Partners, L.P. 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Roelof Botha 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Managing Member of Sequoia Grove Manager, LLC 09/21/2021 Signature of Reporting Person Date By: /s/ Jung Yeon Son, by power of attorney for Douglas Leone, a Managing Member of Sequoia Grove Manager, LLC, the manager of Sequoia Grove II, LLC 09/21/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Class B Common Stock is convertible at any time at the option of the holder into the Issuer's Class A Common Stock on a one-to-one basis. The Class B Common Stock will convert automatically into shares of the Issuer's Class A Common Stock on a one-to-one basis upon the earlier of (a) any transfer of the Class B Common Stock by the holder, whether or not for value, subject to certain exceptions or (b) the date that is six monthsfollowing the date on which none of the Issuer's founders is an employee or director of the Issuer (unless a founder has rejoined the Issuer during such six-month period). ( 2 )SC US (TTGP), Ltd. is the general partner of (i) SCGGF III - Endurance Partners Management, L.P., which is the general partner of Sequoia Capital Global Growth Fund III - Endurance Partners, L.P. ("GGF III"), and the general partner of SC U.S. Growth VIII Management, L.P., which is the general partner of Sequoia Capital U.S. Growth Fund VIII, L.P. ("GFVIII"). The directors and stockholders of SC US (TTGP), Ltd. who exercise voting and investment discretion with respect to GGF III are Douglas Leone and Roelof Botha. By virtue of the relationships described in this paragraph, each of SC US (TTGP), Ltd., SCGGF III - Endurance Partners Management, L.P., Douglas Leone and Roelof Botha may be deemed to share voting and dispositive power with respect to the shares held by GGF III. ( 3 )(Continued from Footnote 2) Each of Douglas Leone, Roelof Botha, SC US (TTGP), Ltd., SCGGF III - Endurance Partners Management, L.P. and and SC U.S. Growth VIII Management, L.P. disclaims beneficial ownership of the shares held by GGF III and GF VIII except to the extent of his or its pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or for any other purposes. ( 4 )Sequoia Grove Manager, LLC is the manager of Sequoia Grove II, LLC. As a result, Sequoia Grove Manager, LLC may be deemed to share beneficial ownership with respect to the shares held by Sequoia Grove II, LLC. Sequoia Grove Manager, LLC disclaims beneficial ownership of the shares held by Sequoia Grove II, LLC except to the extent of its pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or for any other purpose.

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).

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