KVYO

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kvyo-20260501

FALSE000183583000018358302026-05-012026-05-01

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 1, 2026

Klaviyo, Inc.

(Exact name of registrant as specified in its charter)

Delaware

(State or other jurisdiction of

incorporation or organization)

001-41806

(Commission File Number)

46-0989964

(IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA

02110

(Address of Principal Executive Offices)

(Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol

Name of each exchange on which registered

Series A common stock, par value $0.001 per share

KVYO

New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition

On May 5, 2026, Klaviyo, Inc. (the "Company") issued a press release announcing financial results for the first quarter ended March 31, 2026. A copy of the release is furnished with this report as Exhibit 99.1.

Item 5.02 - Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On May 1, 2026, Amanda Whalen informed the Company of her intention to step down from her role as Chief Financial Officer of the Company. Ms. Whalen will continue to serve as Chief Financial Officer through August 21, 2026, after which she will move into an advisory role to support a smooth transition. The Company has initiated a formal search for a new Chief Financial Officer.

On May 4, 2026, the Company and Ms. Whalen entered into a consulting agreement (the “Agreement”) setting forth the terms of Ms. Whalen’s post-employment advisory role. Under the Agreement, following the effective date of her departure, Ms. Whalen will serve as an independent contractor until November 16, 2026, and Ms. Whalen’s outstanding equity awards will continue to vest in accordance with their terms during such term. The foregoing description of the Agreement does not purport to be complete and is qualified in its entirety by reference to the Agreement, which is attached hereto as Exhibit 10.1 and is incorporated herein by reference.

Ms. Whalen’s departure is not the result of any disagreement with the Company or related to the Company’s financial performance, accounting practices, internal controls, or operations.

Item 7.01 - Regulation FD Disclosure.

The information contained in Items 2.02 and 7.01 and the accompanying Exhibit 99.1 hereto is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits

(d) The following exhibits are being filed herewith:

Exhibit No.

Description

10.1

Consulting Agreement between Klaviyo, Inc. and Amanda Whalen, dated May 4, 2026

99.1

Press Release issued by Klaviyo, Inc. dated May 5, 2026

104

Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 5th day of May, 2026.

KLAVIYO, INC.

By:

/s/ Amanda Whalen

Name:

Amanda Whalen

Title:

Chief Fina

kvyo-20260210FALSE000183583000018358302026-02-102026-02-10

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 10, 2026

KLAVIYO, INC.

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification No.)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On February 10, 2026, Klaviyo, Inc. (“Klaviyo” or the “Company”) issued a press release announcing financial results for the quarter and fiscal year ended December 31, 2025. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated February 10, 2026

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 10th day of February, 2026.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20251105FALSE000183583000018358302025-11-052025-11-05

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 5, 2025 Klaviyo, Inc. (Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On November 5, 2025, Klaviyo, Inc. issued a press release announcing financial results for the third quarter ended September 30, 2025. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated November 5, 2025

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 5th day of November, 2025.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20250805FALSE000183583000018358302025-08-052025-08-05

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 5, 2025 Klaviyo, Inc. (Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On August 5, 2025, Klaviyo, Inc. issued a press release announcing financial results for the second quarter ended June 30, 2025. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated August 5, 2025

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 5th day of August, 2025.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20250506FALSE000183583000018358302025-05-062025-05-06

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 6, 2025 Klaviyo, Inc. (Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On May 6, 2025, Klaviyo, Inc. issued a press release announcing financial results for the first quarter ended March 31, 2025. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated May 6, 2025

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 6th day of May, 2025.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20250219FALSE000183583000018358302025-02-192025-02-19

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 19, 2025

KLAVIYO, INC.

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification No.)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On February 19, 2025, Klaviyo, Inc. (“Klaviyo” or the “Company”) issued a press release announcing financial results for the quarter and fiscal year ended December 31, 2024. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated February 19, 2025

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 19th day of February, 2025.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20241106FALSE000183583000018358302024-11-062024-11-06

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 6, 2024 Klaviyo, Inc. (Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On November 6, 2024, Klaviyo, Inc. issued a press release announcing financial results for the third quarter ended September 30, 2024. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated November 6, 2024

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 6th day of November, 2024.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20240807FALSE000183583000018358302024-08-072024-08-07

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 7, 2024 Klaviyo, Inc. (Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On August 7, 2024, Klaviyo, Inc. issued a press release announcing financial results for the second quarter ended June 30, 2024. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated August 7, 2024

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 7th day of August, 2024.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20240508FALSE000183583000018358302024-05-082024-05-08

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 8, 2024 Klaviyo, Inc. (Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On May 8, 2024, Klaviyo, Inc. issued a press release announcing financial results for the first quarter ended March 31, 2024. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated May 8, 2024

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 8th day of May, 2024.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20240227FALSE000183583000018358302024-02-272024-02-27

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 27, 2024

KLAVIYO, INC.

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (IRS Employer Identification No.)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company    ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On February 27, 2024, Klaviyo, Inc. (“Klaviyo” or the “Company”) issued a press release announcing financial results for the quarter and fiscal year ended December 31, 2023. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 8.01 - Other Events In connection with the Company’s initial public offering (the “IPO”) of Series A common stock, par value $0.001 per share (the “Series A common stock”), each of the Company’s officers, directors, and holders of substantially all of the Company’s Series A common stock and securities convertible into or exchangeable for shares of the Company’s Series A common stock entered into lock-up agreements with the underwriters for the IPO that, subject to certain exceptions, restrict such holder’s ability to sell or transfer their shares or otherwise engage in certain transactions related thereto. Such restrictions terminate on the earlier of (i) the opening of trading on the second trading day immediately following the Company’s release of earnings for the quarter ended December 31, 2023 and (ii) 180 days after the date of the final prospectus relating to the IPO (the “Restricted Period”).

On February 27, 2024, the Company publicly announced its earnings for the quarter ended December 31, 2023, and, as a result, the Restricted Period is expected to end at the opening of trading on February 29, 2024.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated February 27, 2024

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 27th day of February, 2024.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer

kvyo-20231107FALSE000183583000018358302023-11-072023-11-07

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (date of earliest event reported): November 7, 2023

KLAVIYO, INC.

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-41806 (Commission File Number) 46-0989964 (I.R.S. Employer Identification Number)

125 Summer Street, 6th Floor, Boston, MA 02110

(Address of Principal Executive Offices) (Zip Code)

(617) 213-1788

(Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Series A common stock, par value $0.001 per shareKVYONew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 12b-2 of the Exchange Act. Emerging growth company    ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 - Results of Operations and Financial Condition On November 7, 2023, Klaviyo, Inc. issued a press release announcing financial results for the third quarter ended September 30, 2023. A copy of the release is furnished with this report as Exhibit 99.1.

The information in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 - Financial Statements and Exhibits (d) The following exhibits are being filed herewith:

Exhibit No.Description 99.1Press Release issued by Klaviyo, Inc. dated November 7, 2023

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized on this 7th day of November, 2023.

KLAVIYO, INC.

By: /s/ Amanda Whalen Name: Amanda Whalen Title: Chief Financial Officer