[Form 4] Klaviyo, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Summit Partners entities reported the disposition of 500,000 shares of Klaviyo, Inc. Series A common stock on 08/21/2025; the sale is reported as a distribution to facilitate bona fide charitable gifts and was effected at a $0 price in the Form 4 filing. Following the reported transaction, the reporting persons show 0 shares beneficially owned. The filing identifies Summit Partners, L.P. as manager of the funds holding the shares and names three investment committee members who may be deemed to have voting and dispositive authority, while disclaiming beneficial ownership except for any pecuniary interest.

Positive

• Transparent disclosure of the 500,000-share disposition and the charitable purpose (J(1) code) provides clarity to investors
• Detailed chain of authority is explained, identifying the manager and investment committee, which improves governance transparency

Negative

• No sale proceeds disclosed (transaction price listed as $0), which limits visibility into any economic impact beyond charitable distribution
• Reporting shows 0 shares owned after the disposition, removing these entities from future direct insider alignment with shareholders in this class

Insights

Securities Analyst

TL;DR: A material insider disposition of 500,000 Series A shares was reported as a charitable distribution; reporting parties now show no beneficial ownership.

The Form 4 documents a non-derivative disposition of 500,000 Series A shares on 08/21/2025, allocated as 307,809 shares from Fund IX-A and 192,191 shares from Fund IX-B to facilitate charitable gifts. The transaction is categorized with transaction code J(1) indicating a distribution in connection with charitable donations. The filing clarifies the chain of management and potential voting/dispositive authority through Summit Partners entities and three named committee members, while including a customary disclaimer of beneficial ownership except for pecuniary interest. For investors, this is a transparent insider action without explicit sale proceeds or trading for liquidity.

Corporate Governance Expert

TL;DR: Governance disclosure details control structure and a disclaimer of beneficial ownership; the charitable distribution is properly disclosed.

The filing appropriately discloses the disposition mechanics and the indirect ownership path: Summit Partners, L.P. manages the chain of entities culminating in Fund IX-A and Fund IX-B. The explanation clarifies who may be deemed to have voting and dispositive authority while expressly disclaiming beneficial ownership beyond pecuniary interest. This level of disclosure aligns with Section 16 reporting expectations for related-party or manager-led transactions and provides investors clear attribution of responsibility for the reported securities.

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
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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^*

SUMMIT PARTNERS L P

(Last) (First) (Middle)

222 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Klaviyo, Inc. [ KVYO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
08/21/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

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
Series A Common Stock, par value $0.001 per share	08/21/2025		J(1)		500,000	D	$0	0	I	See footnote(2)

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

1. Name and Address of Reporting Person^*

SUMMIT PARTNERS L P

(Last) (First) (Middle)

222 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Summit Partners Growth Equity Fund IX-A, L.P.

(Last) (First) (Middle)

222 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Summit Partners Growth Equity Fund IX-B, L.P.

(Last) (First) (Middle)

222 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. Represents a distribution of 307,809 shares of Series A common stock, par value $0.001 per share ("Series A Common Stock") held by Summit Partners Growth Equity Fund IX-A, L.P. ("Fund IX-A") and 192,191 shares of Series A Common Stock held by Summit Partners Growth Equity Fund IX-B, L.P. ("Fund IX-B"), in each case to facilitate bona fide charitable gifts.

2. Summit Partners, L.P. is the manager of Summit Partners GE IX, LLC, which is the general partner of Summit Partners GE IX, LP, which is the general partner of Fund IX-A and Fund IX-B. The investment committee of Summit Partners, L.P., is currently composed of Peter Y. Chung, Scott C. Collins, and Peter L. Rottier, who may be deemed to have voting and dispositive authority over, and therefore beneficial ownership of, the reported securities. Each of the foregoing entities, Mr. Chung, Mr. Collins, and Mr. Rottier disclaims beneficial ownership of the shares, except to the extent of such person's or entity's pecuniary interest therein and the filing of this statement shall not be deemed an admission that any of the foregoing entities or persons are, for purposes of Section 16 of the Act or otherwise, the beneficial owner of any equity securities covered by this statement.

	/s/ Adam Hennessey, as attorney-in-fact for Summit Partners, L.P.	08/22/2025
	/s/ Adam Hennessey, as attorney-in-fact for Summit Partners Growth Equity Fund IX-A, L.P.	08/22/2025
	/s/ Adam Hennessey, as attorney-in-fact for Summit Partners Growth Equity Fund IX-B, L.P.	08/22/2025
	** 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.
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FAQ

What did Summit Partners report on Form 4 for Klaviyo (KVYO)?

They reported a disposition of 500,000 shares of Series A common stock on 08/21/2025, noted as a distribution to facilitate charitable gifts (transaction code J(1)).

How many shares came from each Summit Partners fund?

307,809 shares were distributed from Summit Partners Growth Equity Fund IX-A and 192,191 shares from Fund IX-B, per the filing.

What is the beneficial ownership after the reported transaction?

The Form 4 reports 0 shares beneficially owned by the reporting persons following the transaction.

Who may have voting or dispositive authority over the reported shares?

The filing states Summit Partners, L.P. manages the relevant entities and the investment committee (Peter Y. Chung, Scott C. Collins, Peter L. Rottier) may be deemed to have voting and dispositive authority, though they disclaim beneficial ownership except for pecuniary interest.

Was this transaction a cash sale?

No cash consideration is disclosed; the transaction price is listed as $0 and described as a distribution for charitable gifts.