Morgan Stanley discloses 8.4% stake in Klaviyo on Schedule 13G

Rhea-AI Filing Summary

Morgan Stanley filed a Schedule 13G reporting beneficial ownership in Klaviyo, Inc. (KVYO) Series A Common Stock. The filing lists 10,321,920 shares beneficially owned, representing 8.4% of the class as of the 09/30/2025 event date. The firm reports 0 shares with sole voting or dispositive power, 6,785,764 shares with shared voting power, and 10,321,920 shares with shared dispositive power.

Morgan Stanley certifies the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control. The reporting person is identified as a Delaware entity (Type: HC, CO), referencing CUSIP 49845K101. The issuer’s principal office is listed in Boston, MA.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Klaviyo, Inc.

(Name of Issuer)

Series A Common Stock

(Title of Class of Securities)

49845K101

(CUSIP Number)

09/30/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 49845K101

1

Names of Reporting Persons

Morgan Stanley

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 6,785,764.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 10,321,920.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,321,920.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.4 %

12

Type of Reporting Person (See Instructions)

HC, CO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Klaviyo, Inc.
(b)	Address of issuer's principal executive offices: 125 SUMMER STREET, FLOOR 6, BOSTON, MA, 02110
Item 2.
(a)	Name of person filing: Morgan Stanley
(b)	Address or principal business office or, if none, residence: 1585 Broadway, New York, NY 10036
(c)	Citizenship: Delaware
(d)	Title of class of securities: Series A Common Stock
(e)	CUSIP No.: 49845K101
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: See the response(s) to Item 9 on the attached cover page(s).
(b)	Percent of class: 8.4 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See the response(s) to Item 5 on the attached cover page(s).
	(ii) Shared power to vote or to direct the vote: See the response(s) to Item 6 on the attached cover page(s).
	(iii) Sole power to dispose or to direct the disposition of: See the response(s) to Item 7 on the attached cover page(s).
	(iv) Shared power to dispose or to direct the disposition of: See the response(s) to Item 8 on the attached cover page(s).
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. * In Accordance with the Securities and Exchange Commission Release No. 34-39538 (January 12, 1998) (the "Release"), this filing reflects the securities beneficially owned, or that may be deemed to be beneficially owned, by certain operating units (collectively, the "MS Reporting Units") of Morgan Stanley and its subsidiaries and affiliates (collectively, "MS"). This filing does not reflect securities, if any, beneficially owned by any operating units of MS whose ownership of securities is disaggregated from that of the MS Reporting Units in accordance with the Release.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Morgan Stanley

Signature:	Chris O'Hara
Name/Title:	Authorized Signatory, Morgan Stanley
Date:	11/07/2025

FAQ

What stake did Morgan Stanley report in Klaviyo (KVYO)?

Morgan Stanley reported beneficial ownership of 10,321,920 shares, or 8.4% of Klaviyo’s Series A Common Stock.

What voting and dispositive powers were disclosed for KVYO?

Morgan Stanley disclosed 0 sole voting, 6,785,764 shared voting, 0 sole dispositive, and 10,321,920 shared dispositive power.

What is the Date of Event for Morgan Stanley’s 13G on KVYO?

The Date of Event is 09/30/2025.

What certification accompanies the 13G filing for KVYO?

It certifies the securities were acquired and are held in the ordinary course of business, not to change or influence control.

What class and CUSIP were reported for Klaviyo in this 13G?

The filing covers Series A Common Stock with CUSIP 49845K101.

Who is the reporting person and where are they organized?

The reporting person is Morgan Stanley, organized in Delaware (Type: HC, CO).