Klaviyo director plans sale of 2,328 shares

Director Susan St. Ledger has filed a Form 144 to potentially sell 2,328 Klaviyo Series A shares under Rule 144 through Fidelity Brokerage Services LLC.

Available on EDGAR 09/11/2026 - 10:42 AM EDT Accepted by SEC EDGAR 09/11/2026 - 10:42 AM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Klaviyo, Inc. (KVYO) is the issuer for a proposed sale of its Series A common stock under Rule 144 by director Susan St. Ledger. The notice covers 2,328 shares, with an aggregate market value of $37,085.04, to be sold through Fidelity Brokerage Services LLC on or about September 11, 2026 on the NYSE. The Series A shares outstanding are listed as 126,937,933 shares, a baseline figure, not the amount being sold.

Key Figures

Shares to be sold: 2,328 shares Aggregate market value of shares to be sold: $37,085.04 Series A shares outstanding: 126,937,933 shares +3 more

6 metrics

Shares to be sold 2,328 shares Series A shares covered by the Form 144 notice for Susan St. Ledger

Aggregate market value of shares to be sold $37,085.04 Value of the 2,328 Series A shares proposed for sale

Series A shares outstanding 126,937,933 shares Outstanding Klaviyo, Inc. Series A shares noted in the Form 144

Approximate date of sale September 11, 2026 Expected start date for the Rule 144 sale on the NYSE

Acquisition date of securities June 9, 2026 Date the restricted stock vested as compensation from the issuer

Issuer phone number 800-338-1744 Contact phone number for Klaviyo, Inc.

Key Terms

Rule 144, restricted stock vesting, Form 144, attorney-in-fact

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

restricted stock vesting financial

"Series A | 06/09/2026 | Restricted Stock Vesting | Issuer"

Restricted stock vesting is the timetable and conditions under which shares granted to employees or insiders become fully owned and can be sold, typically requiring continued work or meeting performance goals. It matters to investors because large blocks of shares can become tradable at once, which can change share supply and price, and because vesting aligns insiders’ incentives with the company’s long‑term performance—think of it like a timed unlock that both rewards and locks in key people.

Form 144 regulatory

"144: Filer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

attorney-in-fact regulatory

"as attorney-in-fact for Susan St. Ledger."

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What transaction is disclosed for KVYO in this Form 144?

The filing discloses a proposed sale under Rule 144 by director Susan St. Ledger of 2,328 shares of Klaviyo, Inc. Series A common stock, with an aggregate market value of $37,085.04, to be executed through Fidelity Brokerage Services LLC.

How many Klaviyo (KVYO) shares are proposed to be sold and at what value?

The notice covers 2,328 Series A shares of Klaviyo, Inc., with an aggregate market value of $37,085.04. These figures represent the amount subject to the Form 144 filing, not the company’s total outstanding shares.

Who is selling Klaviyo (KVYO) shares under this Form 144 and in what capacity?

The securities are to be sold for the account of Susan St. Ledger, identified as a Director of Klaviyo, Inc. The Form 144 is signed by Emily Navaro as a duly authorized representative of Fidelity Brokerage Services LLC, acting as attorney-in-fact for St. Ledger.

When are the Klaviyo (KVYO) shares expected to be sold under this notice?

The approximate date of sale stated is September 11, 2026, with the shares to be sold on the NYSE. This date reflects when the seller expects to begin transactions under this Form 144 notice.

What is the origin of the Klaviyo (KVYO) shares being sold?

The filing states the securities to be sold are Series A shares acquired through Restricted Stock Vesting from the Issuer on June 9, 2026, categorized as Compensation in the Form 144 disclosure.

How many Klaviyo (KVYO) Series A shares are outstanding according to this filing?

The Form 144 lists 126,937,933 Series A shares of Klaviyo, Inc. as outstanding. This is a context figure for the company’s capital structure and is separate from the 2,328 shares proposed to be sold under this notice.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001673606
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Klaviyo, Inc.
SEC File Number	001-41806
Address of Issuer	125 SUMMER STREET, FLOOR 6 BOSTON MASSACHUSETTS 02110
Phone	800-338-1744
Name of Person for Whose Account the Securities are To Be Sold	St. Ledger Susan
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Series A	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	2328	37085.04	126937933	09/11/2026	NYSE

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Series A	06/09/2026	Restricted Stock Vesting	Issuer			2328	06/09/2026	Compensation

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	09/11/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	06/12/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Emily Navaro, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Susan St. Ledger.
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)