STOCK TITAN

Klaviyo (KVYO) co-CEO converts Series B and sells 200K shares

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Klaviyo, Inc. co-CEO Andrew Bialecki reported a mix of share conversions and sales. He converted 200,000 shares of Series B Common Stock into 200,000 shares of Series A Common Stock, then sold 141,316 Series A shares at a weighted average of $14.97 and 58,684 shares at a weighted average of $14.46 in open-market transactions. These trades were executed under a Rule 10b5-1 trading plan adopted on May 20, 2025. Following the derivative conversion, he directly held 67,144,118 shares of Series B Common Stock and had additional indirect interests in shares held by several family trusts and by his spouse, with beneficial ownership of those indirect holdings disclaimed except to the extent of any pecuniary interest.

Positive

  • None.

Negative

  • None.
Insider Bialecki Andrew
Role Co-Chief Executive Officer
Sold 200,000 shs ($2.92M)
Type Security Shares Price Value
Conversion Series B Common Stock 200,000 $0.00 --
Conversion Series A Common Stock 200,000 $0.00 --
Sale Series A Common Stock 58,684 $14.97 $878K
Sale Series A Common Stock 141,316 $14.46 $2.04M
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 — 67,144,118 shares (Direct, null); Series A Common Stock — 200,000 shares (Direct, null); Series B Common Stock — 7,517,410 shares (Indirect, By The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023)
Footnotes (1)
  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 $14.74 to $15.73 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. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $14.30 to $14.73 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.
Net shares sold 200,000 shares Net open-market sale of Series A Common Stock on 2026-05-12
First sale tranche 141,316 shares at $14.97/share Weighted average price; multiple trades between $14.74 and $15.73
Second sale tranche 58,684 shares at $14.46/share Weighted average price; multiple trades between $14.30 and $14.73
Shares converted 200,000 shares Series B Common Stock converted into Series A Common Stock
Direct Series B holding 67,144,118 shares Series B Common Stock held directly after conversion
Grantor Retained Annuity Trust holding 7,517,410 underlying shares Series A underlying Series B, held by 2023 GRAT, indirect
Irrevocable GST Trust holdings 517,006 + 517,006 underlying shares Two 2023 GST trusts holding Series B tied to Series A
Spousal holding 43,218 underlying shares Series B tied to Series A, held by spouse, indirect
Rule 10b5-1 trading plan regulatory
"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."
A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.
weighted average price financial
"The price reported in Column 4 is a weighted average price."
Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.
Grantor Retained Annuity Trust financial
"Shares held by the Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023, of which the Reporting Person serves as trustee."
A grantor retained annuity trust (GRAT) is an estate-planning tool where the person who creates the trust transfers assets into it but receives fixed cash payments (an annuity) from the trust for a set number of years; whatever remains after that term passes to designated beneficiaries. It matters to investors because it can shift future appreciation of assets out of the creator’s taxable estate—like putting an asset into a timed vending machine that pays you fixed amounts while any extra value that grows inside the machine goes to heirs with reduced gift or estate tax consequences.
Irrevocable GST Trust financial
"Shares held by the Elizabeth L. Bialecki Irrevocable GST Trust of 2023, of which the Reporting Person serves as a trustee."
Series B Common Stock financial
"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"
beneficial ownership regulatory
"The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
SEC Form 4
FORM 4UNITED 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).
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 MASSACHUSETTS 02110

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
Klaviyo, Inc. [ KVYO ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirectorX10% Owner
XOfficer (give title below)Other (specify below)
Co-Chief Executive Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/12/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

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)
CodeVAmount(A) or (D)Price
Series A Common Stock05/12/2026C(1)200,000A(2)200,000D
Series A Common Stock05/12/2026S(1)58,684D$14.97(3)141,316D
Series A Common Stock05/12/2026S(1)141,316D$14.46(4)0D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Series B Common Stock(2)05/12/2026C(1)200,000 (2) (2)Series A Common Stock200,000$067,144,118D
Series B Common Stock(2) (2) (2)Series A Common Stock7,517,4107,517,410IBy The Andrew P. Bialecki Grantor Retained Annuity Trust I of 2023(5)
Series B Common Stock(2) (2) (2)Series A Common Stock517,006517,006IBy The Elizabeth L. Bialecki Irrevocable GST Trust of 2023(6)
Series B Common Stock(2) (2) (2)Series A Common Stock517,006517,006IBy The Andrew P. Bialecki Irrevocable GST Trust of 2023(7)
Series B Common Stock(2) (2) (2)Series A Common Stock43,21843,218IBy 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 $14.74 to $15.73 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 $14.30 to $14.73 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. 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.
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-Fact05/14/2026
** Signature of Reporting PersonDate
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.
* Form 4: SEC 1474 (03-26)

FAQ

What did Klaviyo (KVYO) co-CEO Andrew Bialecki report in this Form 4?

Andrew Bialecki reported converting 200,000 Series B shares into Series A and selling 200,000 Series A shares in open-market trades. The filing also details his remaining direct Series B holdings and several indirect positions held through family trusts and his spouse.

How many Klaviyo (KVYO) shares did Andrew Bialecki sell and at what prices?

He sold 141,316 shares of Series A Common Stock at a weighted average price of $14.97 and 58,684 shares at a weighted average price of $14.46. Both transactions were open-market sales, with detailed price ranges provided in accompanying footnotes.

Were Andrew Bialecki’s Klaviyo (KVYO) share sales under a Rule 10b5-1 plan?

Yes. The filing states the transactions were effected under a Rule 10b5-1 trading plan adopted on May 20, 2025. Such plans pre-schedule trades, indicating these sales followed a predetermined arrangement rather than discretionary, real-time trading decisions.

What Klaviyo (KVYO) shares does Andrew Bialecki hold directly after these transactions?

After converting 200,000 Series B shares into Series A and completing the reported sales, he directly held 67,144,118 shares of Series B Common Stock. The filing shows no remaining directly held Series A Common Stock following the 200,000-share sale sequence.

What indirect Klaviyo (KVYO) holdings are associated with Andrew Bialecki?

Indirect positions include Series B Common Stock held by his spouse and several 2023 family trusts, covering underlying Series A shares of 43,218, 517,006, 517,006 and 7,517,410. The filing states he disclaims beneficial ownership except to the extent of any pecuniary interest.

What is the relationship between Klaviyo (KVYO) Series A and Series B Common Stock?

Each share of Series B Common Stock is convertible into one share of Series A Common Stock at any time at the holder’s option. Series B will automatically convert into Series A upon specified events in Klaviyo’s certificate of incorporation, and the Series B shares have no expiration date.