What indirect Klaviyo share holdings are reported for Andrew P. Bialecki?

Indirect interests are reported through several 2023 trusts, including 7,517,410 shares via the Andrew P. Bialecki Grantor Retained Annuity Trust I, 517,006 shares via the Elizabeth L. Bialecki Irrevocable GST Trust, 517,006 shares via the Andrew P. Bialecki Irrevocable GST Trust, and 43,218 shares held by his spouse, with beneficial ownership of these trust-held shares disclaimed except for any pecuniary interest.

KVYO CEO Bialecki converts Series B and sells 147k Series A

Q: At what price did the Klaviyo CEO sell the 147,329 Series A shares?

The 147,329 shares of Series A Common Stock were sold at a weighted average price of $27.16 per share , with individual trades ranging from $26.62 to $27.59 .

Q: What is the conversion feature of Klaviyo Series B Common Stock reported here?

Each share of Series B Common Stock is convertible at any time at the holder’s option into one share of Series A Common Stock and will automatically convert into one Series A share upon certain events described in the company’s certificate of incorporation; the Series B stock has no expiration date .

Filing Impact

(Very High)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Klaviyo CEO Andrew P. Bialecki reported the conversion and sale of 147,329 shares of Series A Common Stock on November 18, 2025 under a Rule 10b5-1 trading plan. The transaction involved converting 147,329 shares of Series B Common Stock into Series A Common Stock, followed by a sale of 147,329 Series A shares at a weighted average price of $27.16 per share in multiple trades between $26.62 and $27.59.

Following these transactions, Bialecki directly held 73,845,613 derivative securities representing Series B Common Stock, each convertible into one share of Series A Common Stock. Additional indirect holdings are reported through several 2023 trusts and by his spouse, covering millions of additional shares, with beneficial ownership of those trust-held shares disclaimed except to the extent of any pecuniary interest.

Insider Trade Summary

Net Seller: 147,329 shares ($4,001,456)

Net Sell 7 txns

Insider Bialecki Andrew

Role Chief Executive Officer

Sold 147,329 shs ($4.00M)

Type	Security	Shares	Price	Value
Conversion	Series B Common Stock	147,329	$0.00	--
Conversion	Series A Common Stock	147,329	$0.00	--
Sale	Series A Common Stock	147,329	$27.16	$4.00M
holding	Series B Common Stock	--	--	--
holding	Series B Common Stock	--	--	--
holding	Series B Common Stock	--	--	--
holding	Series B Common Stock	--	--	--

Holdings After Transaction: Series B Common Stock — 73,845,613 shares (Direct); Series A Common Stock — 147,329 shares (Direct); Series B Common Stock — 7,517,410 shares (Indirect, By The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023)

Footnotes (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. 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. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $26.62 to $27.59 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. Shares held by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, of which the Reporting Person serves as 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. 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. 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.

Form 4 Insider Transactions: What Each Field Means →

11/20/2025 - 04:10 PM

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
Estimated average burden
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^*

Bialecki Andrew

(Last)

(First)

(Middle)

C/O KLAVIYO, INC.

125 SUMMER STREET, 6TH FLOOR

(Street)

BOSTON

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)
11/18/2025

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Series A Common Stock	11/18/2025		C⁽¹⁾		147,329	A	⁽²⁾	147,329	D
Series A Common Stock	11/18/2025		S⁽¹⁾		147,329	D	$27.16⁽³⁾	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Series B Common Stock	⁽²⁾	11/18/2025		C⁽¹⁾			147,329	⁽²⁾	⁽²⁾	Series A Common Stock	147,329	$0	73,845,613	D
Series B Common Stock	⁽²⁾							⁽²⁾	⁽²⁾	Series A Common Stock	7,517,410		7,517,410	I	By The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023⁽⁴⁾
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⁽⁵⁾
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⁽⁶⁾
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 $26.62 to $27.59 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. Shares held by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, of which the Reporting Person serves as 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.

5. 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.

6. 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	11/20/2025
	** 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.

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did Klaviyo (KVYO) report on this Form 4?

The filing reports that CEO Andrew P. Bialecki converted 147,329 shares of Series B Common Stock into Series A Common Stock and then sold 147,329 Series A shares on November 18, 2025.

At what price did the Klaviyo CEO sell the 147,329 Series A shares?

The 147,329 shares of Series A Common Stock were sold at a weighted average price of $27.16 per share, with individual trades ranging from $26.62 to $27.59.

Was the Klaviyo CEO trade made under a Rule 10b5-1 plan?

Yes. The filing states that the transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by Andrew P. Bialecki on May 20, 2025.

How many Klaviyo shares does Andrew P. Bialecki hold directly after this transaction?

After the reported transactions, Andrew P. Bialecki directly held 73,845,613 derivative securities of Series B Common Stock, each convertible into one share of Series A Common Stock.

What is the conversion feature of Klaviyo Series B Common Stock reported here?

Each share of Series B Common Stock is convertible at any time at the holder’s option into one share of Series A Common Stock and will automatically convert into one Series A share upon certain events described in the company’s certificate of incorporation; the Series B stock has no expiration date.