ONTF

ontf-202602250001110611FALSE00011106112026-02-252026-02-25

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 25, 2026

ON24, INC.

(Exact name of registrant as specified in its charter)

Delaware001-3996594-3292599 (State or other jurisdiction of incorporation)(Commission File Number)(IRS Employer Identification No.)

301 Howard Street,Suite 1100 San Francisco,

CA94105

(Address of principal executive offices)(Zip Code)

(415) 369-8000 (Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K 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 classTrading SymbolName of each exchange on which registered Common stock, par value $0.0001 per shareONTFThe 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 February 25, 2026, ON24, Inc. (the “Company”), issued a press release announcing its financial results for the fourth quarter and full year ended December 31, 2025. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference.

The information contained in this report, including Exhibit 99.1 attached hereto, is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any other filing with the Securities and Exchange Commission made by the Company regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Item 9.01    Exhibits. (d) Exhibits.

Exhibit No.Description

99.1 Press Release dated February 25, 2026

104Cover Page Interactive Data File (formatted as Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: February 25, 2026 ON24, Inc.

By:/s/ Steven Vattuone Steven Vattuone Chief Financial Officer

ontf-202511100001110611FALSE00011106112025-11-102025-11-10

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): November 10, 2025

ON24, INC.

(Exact name of registrant as specified in its charter)

Delaware001-3996594-3292599 (State or other jurisdiction of incorporation)(Commission File Number)(IRS Employer Identification No.)

301 Howard Street,Suite 1100 San Francisco,

CA94105

(Address of principal executive offices)(Zip Code)

(415) 369-8000 (Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K 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 classTrading SymbolName of each exchange on which registered Common stock, par value $0.0001 per shareONTFThe 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 November 10, 2025, ON24, Inc. (the “Company”), issued a press release announcing its financial results for the third quarter ended September 30, 2025. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference.

The information contained in this report, including Exhibit 99.1 attached hereto, is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any other filing with the Securities and Exchange Commission made by the Company regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Item 7.01     Regulation FD Disclosure. The Company has received indications of interest for a potential acquisition of the Company. The Board is evaluating the indications of interest with Goldman Sachs, its financial advisor. There can be no assurances as to the outcome of this process.

This document contains “forward-looking statements” under applicable securities laws, including express or implied statements about the outcome of our process to evaluate indications of interest, which are subject to inherent risks and uncertainties, including our ability to attract new customers and expand sales to existing customers; declines in our growth rate; fluctuation in our performance; our history of net losses; competition; technological development in our markets; decline in demand for our solutions; our ability to expand our sales and marketing capabilities and otherwise achieve our growth; the impact of the resumption of in-person marketing activities on our customer growth rate; disruptions or other issues with our technology or third-party services; compliance with data privacy, import and export controls, customs, sanctions and other laws and regulations; intellectual property matters; and matters relating to our common stock, along with the other risks and uncertainties discussed in the filings we make from time to time with the Securities and Exchange Commission. Actual results may differ materially from those indicated in forward-looking statements, and you should not place undue reliance on them. All statements herein are based only on information currently available to us and speak only as of the date hereof. Except as required by law, we undertake no obligation to update any such statement.

Item 9.01    Exhibits. (d) Exhibits.

Exhibit No.Description

99.1 Press Release dated November 10, 2025

104Cover Page Interactive Data File (formatted as Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly

ontf-202508070001110611FALSE00011106112025-08-072025-08-07

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, 2025

ON24, INC.

(Exact name of registrant as specified in its charter)

Delaware001-3996594-3292599 (State or other jurisdiction of incorporation)(Commission File Number)(IRS Employer Identification No.)

50 Beale Street, 8th Floor San Francisco,

CA94105

(Address of principal executive offices)(Zip Code)

(415) 369-8000 (Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K 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 classTrading SymbolName of each exchange on which registered Common stock, par value $0.0001 per shareONTFThe 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 August 7, 2025, ON24, Inc. (the “Company”), issued a press release announcing its financial results for the second quarter ended June 30, 2025. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference.

The information contained in this report, including Exhibit 99.1 attached hereto, is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any other filing with the Securities and Exchange Commission made by the Company regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Item 9.01 Exhibits. (d) Exhibits.

Exhibit No.Description

99.1 Press Release dated August 7, 2025

104Cover Page Interactive Data File (formatted as Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: August 7, 2025 ON24, Inc.

By:/s/ Steven Vattuone Steven Vattuone Chief Financial Officer