# EDGAR Filing Document

**Accession Number:** 0001835830
**File Stem:** 0001835830-25-000069
**Filing Date:** 2025-6
**Character Count:** 8947
**Document Hash:** 8e979371fe8d416fee3fd6d72c115746
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001835830-25-000069.hdr.sgml**: 20250611

**ACCESSION NUMBER**: 0001835830-25-000069

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250611

**FILED AS OF DATE**: 20250611

**DATE AS OF CHANGE**: 20250611

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Bialecki Andrew
- **CENTRAL INDEX KEY:** 0001991099

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41806
- **FILM NUMBER:** 251040359

**MAIL ADDRESS:**
- **STREET 1:** KLAVIYO, INC.
- **STREET 2:** 125 SUMMER STREET, 6TH FLOOR
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Klaviyo, Inc.
- **CENTRAL INDEX KEY:** 0001835830
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-PREPACKAGED SOFTWARE [7372]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 125 SUMMER STREET, FLOOR 6
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110
- **BUSINESS PHONE:** 800-338-1744

**MAIL ADDRESS:**
- **STREET 1:** 125 SUMMER STREET, FLOOR 6
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] 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**<sup>*</sup><br>Bialecki Andrew<br><sub>(Last) (First) (Middle)</sub><br>C/O KLAVIYO, INC.<br>125 SUMMER STREET, 6TH FLOOR<br><sub>(Street)</sub><br>BOSTON, MA 02110<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2025-06-11 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_Chief Executive Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Klaviyo, Inc. [ KVYO ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Series A Common Stock | 2025-06-11 |  | C |  | 100000 | A | <sup>(1)(2)</sup> | 100000 | D |  |
| Series A Common Stock | 2025-06-11 |  | G<sup>(3)</sup> |  | 100000 | D | $0 | 0 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Series B Common Stock | <sup>(1)</sup> | 2025-06-11 |  | C |  |  | 100000 | <sup>(1)</sup> | <sup>(1)</sup> | Series A Common Stock | 100000 | $0 | 74773276 | D |  |
| Series B Common Stock | <sup>(1)</sup> |  |  |  |  |  |  | <sup>(1)</sup> | <sup>(1)</sup> | Series A Common Stock | 11945830 |  | 11945830 | I | By The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023<sup>(4)</sup> |
| Series B Common Stock | <sup>(1)</sup> |  |  |  |  |  |  | <sup>(1)</sup> | <sup>(1)</sup> | Series A Common Stock | 517006 |  | 517006 | I | By The Elizabeth L. Bialecki Irrevocable GST Trust of 2023<sup>(5)</sup> |
| Series B Common Stock | <sup>(1)</sup> |  |  |  |  |  |  | <sup>(1)</sup> | <sup>(1)</sup> | Series A Common Stock | 517006 |  | 517006 | I | By The Andrew P. Bialecki Irrevocable GST Trust of 2023<sup>(6)</sup> |
| Series B Common Stock | <sup>(1)</sup> |  |  |  |  |  |  | <sup>(1)</sup> | <sup>(1)</sup> | Series A Common Stock | 43218 |  | 43218 | I | By spouse |

---

### Footnotes:

(1) 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.

(2) The Reporting Person directed the transfer of 100,000 shares of their Series B Common Stock in connection with a bona fide gift to a donor-advised fund, resulting in the automatic conversion of the shares into Series A Common Stock upon execution of the transfer pursuant to the Issuer's certificate of incorporation.

(3) Represents a bona fide gift of 100,000 shares of stock from the Reporting Person to a donor-advised fund. The Reporting Person directed the transfer of 100,000 shares of their Series B Common Stock, resulting in the automatic conversion of the shares into Series A Common Stock upon execution of the transfer.

(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.

**Signature:** /s/ Landon Edmond, Attorney-in-Fact  
**Date:** 2025-06-11

### Remarks:

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.**