Ledger Susan St. - 18 May 2026 Form 4 Insider Report for Klaviyo, Inc. (KVYO)

Reporting relationship: Director
Issuer ticker: KVYO
Reported as of: 18 May 2026
Net transaction value: -$133,196
SEC form: 4
Accepted by SEC: 20 May 2026, 20:05:43 UTC
Prior SEC filing: 12 Sep 2025
Next SEC filing: 11 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Landon Edmond, Attorney-in-Fact

Key filing fact

Ledger Susan St. filed Form 4 for Klaviyo, Inc. (KVYO) on 20 May 2026.

Key facts

This page summarizes Ledger Susan St.'s Form 4 filing for Klaviyo, Inc. (KVYO).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 20 May 2026, 20:05.

Change

Previous filing in this sequence was filed on 12 Sep 2025.
Current net transaction value: -$133,196.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001673606 Primary reporting owner

St. Ledger Susan

Relationship: Director
Address: C/O KLAVIYO, INC., 125 SUMMER STREET, 6TH FLOOR, BOSTON
Signature: /s/ Landon Edmond, Attorney-in-Fact
Signature date: 20 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

KVYO transaction

Series A Common Stock

Conversion of derivative security

Transaction value
Shares: +9,334
Change %: +85%
Price
Shares after: 20,273
Date: 18 May 2026
Ownership: Direct
Footnotes: F1, F2

KVYO transaction

Series A Common Stock

Sale

Transaction value: $133,196
Shares: -9,334
Change %: -46%
Price: $14.27
Shares after: 10,939
Date: 18 May 2026
Ownership: Direct
Footnotes: F1, F3

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

KVYO transaction Derivative

Series B Common Stock

Conversion of derivative security

Transaction value
Shares: -9,334
Change %: -16%
Price: $0.000000^*
Shares after: 50,166
Date: 18 May 2026
Ownership: Direct
Underlying class: Series A Common Stock
Underlying amount: 9,334
Exercise price
Footnotes: F1, F2, F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 4 footnotes

Footnote F1

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 11, 2025.

Footnote F2

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.

Footnote F3

Consists of (i) 5,119 shares of Series A Common Stock and (ii) 5,820 unvested restricted stock units awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement.

Footnote F4

Consists of 50,166 shares of Series B Common Stock.