BIALECKI ANDREW (Co-Chief Executive Officer) sold 200K shares of KLAVIYO, INC. on the open market

Open‑market sale worth $2.98M. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 1 sale

BIALECKI ANDREW

Filed: 5/21/2026ACC: 0001470831-26-000479

InsiderBIALECKI ANDREWCIK 1991099

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IssuerKLAVIYO, INC.CIK 1835830

DirectorOfficer10% Owner· Co-Chief Executive Officer

Since Mar 2026

-200K

Net shares

Net seller

$2.98M

Total sold

Open market trades

0B · 1S

Total transactions

200K acquired · 400K disposed

Non-Derivative Transactions2

Series A Common Stock

Direct

C · Conversion

+200K

Price / share

—

Trade value

—

% of position

New position

5/19/2026

0.00→200K

Series A Common Stock

Direct

S · Sale

−200K

Price / share

$14.88

Trade value

$2.98M

% of position

New position

5/19/2026

200K→0.00

Total

Net shares

+0.00

Net value

-$2.98M

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Series A Common Stock Direct	5/19/2026	C · Conversion	+200K	—	—	New position	0.00	200K
Series A Common Stock Direct	5/19/2026	S · Sale	−200K	$14.88	$2.98M	New position	200K	0.00
Total			+0.00		-$2.98M

Derivative Transactions1

Series B Common Stock

Direct

C · Conversion

Converts to

Series A Common Stock

200K shares

−200K

Strike price

Held after

66.94M

Exercisable

—

5/19/2026

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Series B Common Stock Direct	Series A Common Stock200K shares	5/19/2026	C · Conversion	−200K		—	66.94M

Non-Derivative Holdings (Post-Transaction)0

No non-derivative holdings reported

Derivative Holdings (Post-Transaction)4

Series B Common Stock

Indirect

Underlying security

Series A Common Stock

Underlying shares

7.52M

Shares owned

7.52M

Exercise price

Expiration

—

Exercise window

—

Series B Common Stock

Indirect

Underlying security

Series A Common Stock

Underlying shares

517.01K

Shares owned

517.01K

Exercise price

Expiration

—

Exercise window

—

Series B Common Stock

Indirect

Underlying security

Series A Common Stock

Underlying shares

517.01K

Shares owned

517.01K

Exercise price

Expiration

—

Exercise window

—

Series B Common Stock

Indirect

Underlying security

Series A Common Stock

Underlying shares

43.22K

Shares owned

43.22K

Exercise price

Expiration

—

Exercise window

—

Total

Underlying

8.59M

Owned

8.59M

Security	Underlying	Exercise Window	Expiration	Underlying Shares	Shares Owned
Series B Common Stock Indirect	Series A Common Stock	—	—	7.52M	7.52M
Series B Common Stock Indirect	Series A Common Stock	—	—	517.01K	517.01K
Series B Common Stock Indirect	Series A Common Stock	—	—	517.01K	517.01K
Series B Common Stock Indirect	Series A Common Stock	—	—	43.22K	43.22K
Total				8.59M	8.59M