KVYO insider Andrew Bialecki converts and sells 226,382 shares at ~$32

Rhea-AI Filing Summary

Andrew Bialecki, Klaviyo, Inc. Chief Executive Officer and a >10% owner, reported transactions in the company’s common stock executed under a Rule 10b5-1 trading plan. On 09/16/2025 the reporting person converted 226,382 shares of Series B common stock into Series A common stock and sold a total of 226,382 Series A shares in two blocks: 140,921 shares at a weighted average price of $32.71 and 85,461 shares at a weighted average price of $31.76. The Form 4 lists various indirect holdings through trusts and shows transfers and ownership details for those trusts. The filing was submitted by an attorney-in-fact.

Positive

• Transactions executed under a Rule 10b5-1 plan, indicating pre-established trading instructions adopted May 20, 2025
• Clear disclosure of conversions and trust holdings, including transfers from the grantor retained annuity trust

Negative

• Insider sales of 226,382 Series A shares represent notable insider liquidity that investors may view negatively
• Weighted-average sale prices ($32.71 and $31.76) show realized insider sales within a narrow price range

Insights

Corporate Governance Expert

TL;DR: Insider sales were executed under a pre-established 10b5-1 plan; conversion and trust holdings are disclosed, preserving disclosure compliance.

The report documents that the CEO used a Rule 10b5-1 trading plan adopted May 20, 2025, to convert Series B shares into Series A and sell 226,382 shares in two tranches at weighted average prices of $32.71 and $31.76. The filing clearly discloses indirect holdings through multiple trusts and includes customary disclaimers of beneficial ownership for certain trust-held shares. From a governance perspective, the use of a 10b5-1 plan reduces the likelihood of claims of opportunistic timing, while the detailed trust disclosures help clarify beneficial ownership boundaries.

Securities Analyst

TL;DR: Material insider selling occurred but was structured via an established trading plan; transaction sizes and prices are explicitly reported.

The Form 4 shows a conversion of 226,382 Series B shares into Series A and subsequent sales of the same total amount across two sets of transactions: 140,921 shares at a weighted average of $32.71 and 85,461 shares at a weighted average of $31.76. The report also notes a transfer of 4,428,420 Series B shares previously moved from an annuity trust to the reporting person. These explicit figures allow investors to quantify insider liquidity on that date without requiring inference beyond the filing.

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

X

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^*

Bialecki Andrew

(Last) (First) (Middle)

C/O KLAVIYO, INC.

125 SUMMER STREET, 6TH FLOOR

(Street)

BOSTON MA 02110

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
09/16/2025

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

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

X	Form filed by One Reporting Person
	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	09/16/2025		C(1)		226,382	A	(2)	226,382	D
Series A Common Stock	09/16/2025		S(1)		140,921	D	$32.71(3)	85,461	D
Series A Common Stock	09/16/2025		S(1)		85,461	D	$31.76(4)	0	D

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
Series B Common Stock	(2)	09/16/2025		C(1)			226,382	(2)	(2)	Series A Common Stock	226,382	$0	74,804,827(5)	D
Series B Common Stock	(2)							(2)	(2)	Series A Common Stock	7,517,410		7,517,410(5)	I	By The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023
Series B Common Stock	(2)							(2)	(2)	Series A Common Stock	517,006		517,006	I	By The Elizabeth L. Bialecki Irrevocable GST Trust of 2023(6)
Series B Common Stock	(2)							(2)	(2)	Series A Common Stock	517,006		517,006	I	By The Andrew P. Bialecki Irrevocable GST Trust of 2023(7)
Series B Common Stock	(2)							(2)	(2)	Series A Common Stock	43,218		43,218	I	By spouse

Explanation of Responses:

1. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025.

2. Each share of the Issuer's Series B Common Stock, par value $0.001 per share ("Series B Common Stock"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share ("Series A Common Stock"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date.

3. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $32.02 to $33.01 per share. The Reporting Person undertakes to provide to 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.

4. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $31.32 to $32.01 per share. The Reporting Person undertakes to provide to 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.

5. Reflects 4,428,420 shares of Series B Common Stock previously transferred from the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023 to the Reporting Person.

6. Shares held by the Elizabeth L. Bialecki Irrevocable GST Trust of 2023, of which the Reporting Person serves as a trustee. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose.

7. Shares held by the Andrew P. Bialecki Irrevocable GST Trust of 2023, of which the Reporting Person's spouse serves as a trustee. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose.

Remarks:

	/s/ Landon Edmond, Attorney-in-Fact	09/17/2025
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transactions did Klaviyo (KVYO) insider Andrew Bialecki report?

The filing reports a conversion of 226,382 Series B shares into Series A and sales of 140,921 shares at a weighted average of $32.71 and 85,461 shares at a weighted average of $31.76 on 09/16/2025.

Were the insider transactions for KVYO part of a trading plan?

Yes. The transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 20, 2025.

Does the Form 4 disclose indirect holdings for Andrew Bialecki?

Yes. The Form 4 discloses indirect holdings through multiple trusts, including the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023 and irrevocable GST trusts.

How many shares were transferred from the grantor retained annuity trust to the reporting person?

4,428,420 shares of Series B Common Stock were previously transferred from the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023 to the reporting person, per the filing.

Who signed the Form 4 for the reporting person?

The filing was signed by Landon Edmond, Attorney-in-Fact, on behalf of the reporting person.