Filed by Momentive Global Inc.

Pursuant to Rule 425 Under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: Momentive Global Inc.

Commission File No.: 001-38664

The following communication was first made available on January 14, 2022 to employees of Momentive Global Inc.

When are the special stockholders meetings to approve the transaction being held?

The Momentive special meeting of the stockholders to approve the Zendesk transaction will be held via live webcast on February 25, 2022 at 10:00am Pacific Time.

The Zendesk special meeting of stockholders to approve the transaction will be held concurrently via live webcast on February 25, 2022 at 10:00am Pacific Time.

Can I attend the special stockholder meeting?

In order to attend the Momentive special stockholder meeting, you must have owned shares in Momentive as of January 3, 2022. If you owned shares as of such date, you will be able to attend and vote at the special meeting by registering here - www.cesonlineservices.com/mntv22_vm. If you hold unexercised or unvested Momentive equity awards, but not Momentive shares, you will not be able to attend the meeting. You must register by 10:00 am Pacific Time on February 24, 2022.

To ensure your vote is counted, whether or not you plan on attending the special stockholder meeting, please vote by proxy over the internet or telephone using the instructions included with the proxy card delivered to you or, if you hold your Momentive shares through a bank or broker, by following the instructions provided by your bank or broker.

How do I vote on this transaction?

If you held shares in Momentive as of January 3, 2022 as a result of the vesting or exercise of Momentive equity awards (and have not moved your shares to a different bank or broker), you should have received an email from E*TRADE to the email address attached to your account with information related to the special meeting and instructions on how to vote your shares.

The email will include your control number, which you need to vote your shares and/or attend the special stockholder meeting. The E*TRADE email will come from “id@Proxyvote.com”. If you have not yet received the email, you can expect to receive it in the next few days. Don’t forget to check your spam folder!

If you hold shares in Momentive “of record”, you can vote your shares by proxy over the internet or telephone using the instructions included with the proxy card delivered to you. If you hold shares in Momentive through another bank or broker, your bank or broker will provide you with instructions on how to vote your shares.

You can find additional information on how to attend the stockholder meeting and vote your shares in our proxy statement filed here.

If you have any questions or need assistance voting your shares, please contact Innisfree M&A Incorporated, Momentive’s proxy solicitor, by calling toll-free at (877) 825-8772 (from the U.S. and Canada) or (212) 750-5833 (from other locations).

Additional Information and Where to Find It

This communication relates to a proposed business combination transaction between Zendesk and Momentive. In connection with the proposed transaction, Zendesk filed with the Securities and Exchange Commission (the “SEC”) a registration statement on Form S-4 (the “registration statement”) that includes a joint proxy statement of Zendesk and Momentive and that also constitutes a prospectus of Zendesk with respect to shares of Zendesk common stock to be issued in the proposed transaction (the “joint proxy statement/prospectus”). The definitive joint proxy statement/prospectus and WHITE proxy card of Zendesk or WHITE proxy card of Momentive, as applicable, were first mailed to Zendesk stockholders and Momentive stockholders beginning on or about January 10, 2022. Each of Zendesk and Momentive may also file other relevant documents regarding the proposed transaction with the SEC. BEFORE MAKING ANY VOTING OR INVESTMENT DECISION, INVESTORS AND SECURITY HOLDERS OF ZENDESK AND MOMENTIVE ARE URGED TO READ THE REGISTRATION STATEMENT, JOINT PROXY STATEMENT/PROSPECTUS AND ALL OTHER RELEVANT DOCUMENTS THAT ARE OR WILL BE FILED WITH THE SEC IN CONNECTION WITH THE PROPOSED TRANSACTION, INCLUDING ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT MOMENTIVE, ZENDESK AND THE PROPOSED TRANSACTION.

Investors and security holders may obtain free copies of the joint proxy statement/prospectus and other documents that are filed or will be filed with the SEC by Zendesk or Momentive through the SEC’s website (www.sec.gov). Copies of the documents filed by Zendesk with the SEC also may be obtained free of charge at Zendesk’s investor relations website at https://investor.zendesk.com or upon written request to Zendesk, Inc. at 989 Market Street, San Francisco, CA 94103. Copies of the documents filed with the SEC by Momentive will be available free of charge by accessing Momentive’s investor relations website at investor.momentive.ai or upon written request to Momentive at One Curiosity Way, San Mateo, California 94403.

Participants in the Solicitation

Zendesk, Momentive, their respective directors and certain of their respective executive officers are participants in the solicitation of proxies from the respective stockholders of Zendesk and Momentive in respect of the proposed transaction. Information about Zendesk’s directors and executive officers and their ownership of Zendesk common stock is set forth in Zendesk’s proxy statement for its 2021 Annual Meeting of Stockholders on Schedule 14A filed with the SEC on April 2, 2021. Information about Momentive’s directors and executive officers and their ownership of Momentive’s common stock is set forth in Momentive’s proxy statement for its 2021 Annual Meeting of Stockholders on Schedule 14A filed with the SEC on April 20, 2021. Additional information regarding the interests of the participants in the proxy solicitations is contained in the joint proxy statement/prospectus. You may obtain free copies of these documents as described in the preceding paragraph.

Cautionary Statement Regarding Forward-Looking Statements

This communication may contain forward-looking statements, including, among other things, statements regarding the anticipated benefits of the proposed transaction, the anticipated impact of the proposed transaction on the combined company’s business and future financial and operating results, the expected amount and timing of anticipated synergies from the proposed transaction, the anticipated timing of closing of the proposed transaction and other aspects of Zendesk’s or Momentive’s operations or operating results. Words such as “may,” “should,” “will,” “believe,” “expect,” “anticipate,” “target,” “project,” and similar phrases that denote future expectations or intent regarding the combined company’s financial results, operations, and other matters are intended to identify forward-looking statements. You should not rely upon forward-looking statements as predictions of future events. The outcome of the events described in these forward-looking statements is subject to known and unknown risks, uncertainties, and other factors that may cause future events to differ materially from the forward-looking statements in this communication, including (i) the ability to complete the proposed transaction within the time frame anticipated or at all; (ii) the failure to realize the anticipated benefits of the proposed transaction or those benefits taking longer than anticipated to be realized; (iii) the risk that uncertainty about the proposed transaction may adversely affect relationships with Zendesk’s customers, partners, suppliers, and employees, whether or not the transaction is completed; (iv) the effect of the announcement of the proposed transaction on the ability of Zendesk or Momentive to retain and hire key personnel; (v) the risk that disruptions from the proposed

transaction will harm Zendesk’s or Momentive’s business, including current plans and operations; (vi) current or future litigation related to the proposed transaction and the resulting expense or delay; (vii) the failure to obtain stockholder or regulatory approvals in a timely manner or otherwise; (viii) the occurrence of any event, change or other circumstances that could give rise to the right of one or both of Zendesk or Momentive to terminate the proposed transaction; (ix) the diversion of the attention of the respective management teams of Zendesk and Momentive from their respective ongoing business operations; (x) the ability of Zendesk to successfully integrate Momentive’s operations and technologies; (xi) the ability of Zendesk to implement its plans, forecasts and other expectations with respect to its business after the completion of the transaction and realize expected synergies; (xii) the effect of uncertainties related to the COVID-19 pandemic on U.S. and global markets, Zendesk’s or Momentive’s respective business, operations, revenue, cash flow, operating expenses, hiring, demand for their respective solutions, sales cycles, customer retention, and their respective customers’ businesses and industries; (xiii) risks relating to the market value of Zendesk’s common stock to be issued in the proposed transaction; (xiv) Zendesk’s ability to adapt its products to changing market dynamics and customer preferences or achieve increased market acceptance of its products; (xv) the intensely competitive market in which Zendesk operates; (xvi) the development of the market for software as a service business software applications; (xvii) Zendesk’s substantial reliance on its customers renewing their subscriptions and purchasing additional subscriptions; (xviii) Zendesk’s ability to effectively market and sell its products to larger enterprises; (xix) Zendesk’s ability to develop or acquire and market new products and to support its products on a unified, reliable shared services platform; (xx) Zendesk’s reliance on third-party services, including services for hosting, email, and messaging; (xxi) Zendesk’s ability to retain key employees and attract qualified personnel, particularly in the primary regions Zendesk operates; (xxii) Zendesk’s ability to effectively manage its growth and organizational change, including its international expansion strategy; (xxiii) Zendesk’s expectation that the future growth rate of its revenues will decline, and that, as its costs increase, Zendesk may not be able to generate sufficient revenues to achieve or sustain profitability; (xxiv) Zendesk’s ability to integrate acquired businesses and technologies successfully or achieve the expected benefits of such acquisitions; (xxv) real or perceived errors, failures, or bugs in Zendesk’s products; (xxvi) potential service interruptions or performance problems associated with Zendesk’s technology and infrastructure; (xxvii) Zendesk’s ability to securely maintain customer data and prevent, mitigate, and respond effectively to both historical and future data breaches; (xxviii) Zendesk’s ability to comply with privacy and data security regulations; (xxix) Zendesk’s ability to optimize the pricing for its solutions; and (xxx) other adverse changes in general economic or market conditions. The forward-looking statements contained in this communication are also subject to additional risks, uncertainties, and factors, including those described in Zendesk’s and Momentive’s most recent Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q and other documents filed by either of them from time to time with the SEC. The forward-looking statements included in this communication are made only as of the date hereof. Zendesk and Momentive do not undertake to update any forward-looking statements made in this communication to reflect events or circumstances after the date of this communication or to reflect new information or the occurrence of unanticipated events, except as required by law.

No Offer or Solicitation

This communication is not intended to and shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote of approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.