Klaviyo, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

For the quarterly period ended June 30, 2025

OR

For the transition period from _____ to _____

Commission File Number 001-41806

(Exact name of registrant as specified in its charter)

(617)213-1788

(Registrant’s telephone number, including area code)

(Former name, former address and formal fiscal year, if changed since last report)

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

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. x Yes o No

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). x Yes o No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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. o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). o Yesx No

As of July 31, 2025, there were 116,897,730 shares of the registrant’s Series A common stock and 183,086,637 shares of the registrant’s Series B common stock, each with a par value of $0.001 per share, outstanding.

Table of Contents

Special Note Regarding Forward-Looking Statements

This Quarterly Report on Form 10‑Q contains forward-looking statements within the meaning of the federal securities laws, which are statements that involve substantial risks and uncertainties. Forward-looking statements generally relate to future events or our future financial or operating performance. All statements other than statements of historical fact included in this Quarterly Report on Form 10‑Q, including statements regarding our strategy, future operations, financial position, estimated revenues and losses, projected costs, prospects, plans and objectives of management are forward-looking statements. In some cases, you can identify forward-looking statements because they contain words such as “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “future,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “shall,” “should,” “strategy,” “target,” “will,” “would,” or the negative of these words or other similar terms or expressions that concern our expectations, strategy, plans or intentions. Forward-looking statements contained in this Quarterly Report on Form 10‑Q include, but are not limited to, statements about:

•our expectations regarding our revenue, expenses, and other operating results;

•our ability to acquire new customers and grow our customer base;

•our ability to successfully retain existing customers and expand sales within our existing customer base;

•our ability to increase usage of our platform and upsell and cross-sell additional products and communications channels;

•our ability to move up-market and address enterprise and other larger customers;

•launching new products and adding new product capabilities;

•our ability to leverage artificial intelligence and machine learning and effectively develop and deliver products that incorporate artificial intelligence and machine learning;

•future investments in developing and enhancing our platform and our business;

•our expectations regarding our ability to expand internationally;

•our ability to add more use cases to our platform and increase our presence in other verticals;

•our anticipated capital expenditures and our estimates regarding our capital requirements;

•the estimated size of our addressable market opportunity for our platform;

•investments in our selling and marketing efforts and our ability to promote our brand;

•expectations regarding our integrations with third-party platforms, including Shopify;

•our ability to compete effectively with existing competitors and new market entrants;

•our reliance on our senior management team and our ability to identify, recruit, and retain skilled personnel;

•our growth strategies for our platform and our ability to effectively manage our growth;

•economic and industry trends and other macroeconomic factors, such as fluctuating interest rates, inflation, tariffs, international trade disputes, and changes in U.S. and foreign laws and regulations, and the impact on our customer spending and consumer spending generally; and

•the impact of public health crises and financial, economic, and political events on our industry, business, and results of operations.

We caution you that the foregoing list may not contain all of the forward-looking statements made in this Quarterly Report on Form 10‑Q.

We have based the forward-looking statements contained in this Quarterly Report on Form 10-Q primarily on our current beliefs, expectations, and projections about future events and trends that we believe may affect our business, results of operations, financial condition, and prospects. The outcome of the events described in these forward-looking statements is subject to risks, uncertainties, and other factors described in the section titled “Risk Factors” and elsewhere in this Quarterly Report on Form 10-Q. Moreover, we operate in a very competitive and rapidly changing environment. New risks and uncertainties emerge from time to time, and it is not possible for us to predict all risks and uncertainties that could have an impact on the forward-looking statements contained in this Quarterly Report on Form 10-Q. The results, events, and circumstances reflected in the forward-looking statements may not be achieved or occur, and actual results, events, or circumstances could differ materially from those described, anticipated, or implied in the forward-looking statements. Therefore, you should not rely on any of the forward-looking statements as predictions of future events.

The forward-looking statements made in this Quarterly Report on Form 10‑Q relate only to events as of the date on which the statements are made. We undertake no obligation to update any forward-looking statements made in this Quarterly Report on Form 10‑Q to reflect events or circumstances after the date of this Quarterly Report on Form 10‑Q or to reflect new information or the occurrence of unanticipated events, except as required by law.

Unless the context otherwise indicates, references in this Quarterly Report on Form 10-Q to the terms “Klaviyo,” “the Company,” “we,” “our,” and “us” refer to Klaviyo, Inc. and its subsidiaries.

Risk Factors Summary

Our business is subject to numerous risks and uncertainties that you should be aware of in evaluating our business. The following is a summary of some of these risks and uncertainties. As a result, this risk factor summary does not contain all of the information that may be important to you, and this summary should be read together with the more detailed description of each risk factor below as well as elsewhere in this Quarterly Report on Form 10-Q. Additional risks, beyond those summarized below or discussed elsewhere in this Quarterly Report on Form 10-Q, may apply to our business, activities or operations as currently conducted or as we may conduct them in the future or in the markets in which we operate or may in the future operate.

•Our rapid historical revenue growth is not indicative of our future revenue growth, and we may not be able to sustain our historical revenue growth rate, in the near term and in the future;

•Our business has experienced rapid growth, and we may fail to effectively manage our growth or anticipated growth;

•We have a limited operating history in a rapidly changing industry, which makes it difficult to evaluate our current business and future prospects and increases the risk of your investment;

•We operate in a highly competitive industry, and we may not compete effectively with established companies or new market entrants;

•Our business and success depend, in part, on our ability to successfully integrate with third-party platforms, especially with eCommerce platforms such as Shopify, and there may be disruptions to these third-party platform integrations or our relationships with third-party platform providers;

•Our business and success depend, in part, on the success of our relationships with third parties, such as our marketing agency and technology partners;

•We may experience unfavorable conditions in our industry or the global economy, or reductions in spending on marketing;

•We may not be able to add new customers, retain existing customers, or increase sales to existing customers;

•We have a history of net losses, we anticipate increasing operating expenses in the future, and we may not be able to achieve and maintain profitability in the future;

•As we seek to move up-market, we expect our sales cycle with enterprise customers to be longer than with small-and-mid size businesses and we will be required to scale our operations, including by expanding our sales efforts, which may require considerable time and expense;

•We have historically invested significantly in research and development and expect this investment to continue;

•If we fail to adapt and respond effectively to technological changes, evolving industry standards, changing regulations or changing customer or consumer needs, requirements or preferences, our platform may become less competitive;

•We depend on our senior management team, and may lose one or more members of our senior management team or our key employees, or be unable to attract and retain highly skilled employees;

•We collect, process, store, share, disclose, and use personal information and other data, which subjects us to legal obligations related to privacy and security, and we may fail to comply with these obligations;

•If we or our third-party service providers experience a cybersecurity incident or data breach or unauthorized parties otherwise obtain access to our customers’ data, our data, or our platform, our platform or our products may be perceived as not being secure, our reputation may be harmed, demand for our platform and products may be reduced, and we may incur significant liabilities;

•We may fail to protect our proprietary technology and intellectual property rights;

•We have incorporated and may continue to incorporate artificial intelligence technology into our products and services, which may expose us to additional risks due to the emerging nature of the technology;

•There has been a limited public market for our Series A common stock. The trading price of our Series A common stock may continue to be volatile or may decline regardless of our operating performance, and you may not be able to resell your shares at or above the price at which you purchased those shares; and

•The dual series structure of our common stock has the effect of concentrating voting control with those stockholders who hold shares of our Series B common stock, including our directors, executive officers, and their respective affiliates, and limiting or precluding your ability to influence corporate matters, including the election of directors, amendments of our organizational documents, and any merger, consolidation, sale of all or substantially all of our assets, or other major corporate transaction requiring stockholder approval.