ON24 (ONTF) Agrees to $8.10 Cash Buyout, Indaba Locks Up 10% Stake

Rhea-AI Filing Summary

ON24, Inc. is the target of a planned cash acquisition. The company entered into a Merger Agreement under which an affiliate of Cvent, Inc. (Cvent Atlanta, LLC and its subsidiary Summit Sub Corp.) has agreed to acquire all outstanding ON24 common shares for $8.10 per share in cash. After the merger, ON24 is expected to continue as the surviving company and a wholly owned subsidiary of the buyer.

Indaba Capital Management, L.P., IC GP, LLC and Derek C. Schrier report beneficial ownership of 4,240,256 ON24 shares, representing 10.0% of the common stock based on 42,282,395 shares outstanding as of November 3, 2025. Indaba has entered into a Voting and Support Agreement with the buyer, agreeing to vote its shares in favor of the merger and, with limited exceptions, not to sell or transfer these shares before the agreement expires.

Insights

M&A and shareholder-activism analyst

ON24 agreed to a cash sale at $8.10 per share, with a 10% holder locked in to support the deal.

The filing shows that ON24, Inc. signed a Merger Agreement for all its outstanding common shares to be acquired by an affiliate of Cvent, Inc. for $8.10 per share in cash. After the merger, ON24 would remain as the surviving corporation and become a wholly owned subsidiary of the buyer, shifting investors from an ongoing public equity story to a cash-out transaction if completed.

Indaba Capital Management, L.P., IC GP, LLC and Derek C. Schrier report beneficial ownership of 4,240,256 shares, or 10.0% of ON24’s common stock, based on 42,282,395 shares outstanding as of November 3, 2025. Indaba entered into a Voting and Support Agreement to vote all of these shares in favor of the merger and, subject to limited exceptions, not to sell or transfer them before the agreement’s expiration. The agreement can terminate under certain conditions, including a Company Adverse Recommendation Change as defined in the Merger Agreement.

This combination of a definitive cash merger agreement and a locked-up 10% shareholder indicates substantial committed support from a major holder. Future company disclosures about stockholder votes or any changes to the board’s recommendation, as described in the merger terms, would further shape the outcome of this transaction.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 5)

ON24 INC.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

68339B104

(CUSIP Number)

Zac Rosenberg
Indaba Capital Management, L.P., One Letterman Drive, BLDG D, Suite DM700
San Francisco, CA, 94129
415-680-1030

Ryan Nebel
Dorothy Sluszka, Olshan Frome Wolosky LLP
New York, NY, 10019
212-451-2300

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

12/29/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 68339B104

1

Name of reporting person

Indaba Capital Management, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 4,240,256.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 4,240,256.00

11

Aggregate amount beneficially owned by each reporting person

4,240,256.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

10.0 %

14

Type of Reporting Person (See Instructions)

IA, PN

Comment for Type of Reporting Person:

Based on 42,282,395 shares of common stock of ON24, Inc. (the "Issuer") outstanding as of November 3, 2025, as reported in the Issuer's Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on November 10, 2025.

SCHEDULE 13D

CUSIP No. 68339B104

1

Name of reporting person

IC GP, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 4,240,256.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 4,240,256.00

11

Aggregate amount beneficially owned by each reporting person

4,240,256.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

10.0 %

14

Type of Reporting Person (See Instructions)

HC, OO

Comment for Type of Reporting Person:

Based on 42,282,395 shares of common stock of the Issuer outstanding as of November 3, 2025, as reported in the Issuer's Form 10-Q filed with the SEC on November 10, 2025.

SCHEDULE 13D

CUSIP No. 68339B104

1

Name of reporting person

SCHRIER DEREK C

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 4,240,256.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 4,240,256.00

11

Aggregate amount beneficially owned by each reporting person

4,240,256.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

10.0 %

14

Type of Reporting Person (See Instructions)

IN, HC

Comment for Type of Reporting Person:

Based on 42,282,395 shares of common stock of the Issuer outstanding as of November 3, 2025, as reported in the Issuer's Form 10-Q filed with the SEC on November 10, 2025.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: ON24 INC.
(c)	Address of Issuer's Principal Executive Offices: 301 HOWARD STREET, SUITE 1100, SAN FRANCISCO, CALIFORNIA , 94105.
Item 1 Comment: The following constitutes Amendment No. 5 ("Amendment No. 5") to the Schedule 13D filed with the SEC by Indaba Capital Management, L.P. (the "Investment Manager"), IC GP, LLC ("IC GP") and Derek C. Schrier (collectively, "Indaba" or the "Reporting Persons") on December 20, 2022, as amended by Amendment No. 1 filed on March 13, 2023, Amendment No. 2 filed on January 18, 2024, Amendment No. 3 filed on February 26, 2024, and Amendment No. 4 filed on March 19, 2025. This Amendment No. 5 amends and restates the Schedule 13D as specifically set forth herein. All capitalized terms contained herein but not otherwise defined shall have the meanings ascribed to such terms in the Schedule 13D, as amended. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable.
Item 4.	Purpose of Transaction
	Item 4 of the Schedule 13D is hereby supplemented as follows: On December 29, 2025, the Issuer entered into an Agreement and Plan of Merger (the "Merger Agreement") with Cvent Atlanta, LLC, a Delaware limited liability company ("Parent"), and Summit Sub Corp., a Delaware corporation and wholly-owned subsidiary of Parent ("Merger Sub"). Parent and Merger Sub are affiliated with Cvent, Inc. and have agreed to acquire all of the Issuer's outstanding shares of common stock for $8.10 per share, in cash. Pursuant to and subject to the terms of the Merger Agreement, Merger Sub will merge with and into the Issuer (the "Merger"), with the Issuer continuing as the surviving company and wholly-owned subsidiary of Parent following the proposed transaction, as more fully described in the Form 8-K filed by the Issuer with the SEC on December 30, 2025. Concurrently with the execution of the Merger Agreement, Indaba and certain other parties entered into separate voting and support agreements (each, a "Voting and Support Agreement") with Parent. Pursuant to the Voting and Support Agreement, Indaba agreed, among other things, to (i) vote or cause to be voted all of its shares of common stock of the Issuer in favor of the Merger and the transactions contemplated by the Merger Agreement and (ii) prior to the Expiration Time (as defined in the Voting and Support Agreement) and subject to limited exceptions, not to sell or otherwise transfer any of its shares of common stock other than with the consent of Parent. The Voting and Support Agreement terminates in certain circumstances, including, among others, upon a Company Adverse Recommendation Change (as defined in the Merger Agreement) and by written consent of Parent, the Issuer and each stockholder party thereto. The foregoing description of the Voting and Support Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Voting and Support Agreement, which is attached hereto as Exhibit 99.1.
Item 6.	Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer
	Item 6 of the Schedule 13D is hereby supplemented to add the following: On December 29, 2025, Indaba and Parent entered into the Voting and Support Agreement as defined and described in Item 4 above.
Item 7.	Material to be Filed as Exhibits.
	Item 7 is hereby supplemented to add the following exhibit: 99.1 - Voting and Support Agreement.

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.

Indaba Capital Management, L.P.

Signature:	/s/ Derek C. Schrier
Name/Title:	Derek C. Schrier, Managing Member of IC GP, LLC, its general partner
Date:	12/31/2025

IC GP, LLC

Signature:	/s/ Derek C. Schrier
Name/Title:	Derek C. Schrier, Managing Member
Date:	12/31/2025

SCHRIER DEREK C

Signature:	/s/ Derek C. Schrier
Name/Title:	Derek C. Schrier
Date:	12/31/2025

FAQ

What major transaction involving ON24 (ONTF) is described?

The content describes a Merger Agreement under which Cvent Atlanta, LLC and its wholly owned subsidiary Summit Sub Corp., which are affiliated with Cvent, Inc., have agreed to acquire all outstanding shares of ON24, Inc. common stock. Following the merger, ON24 would continue as the surviving company and become a wholly owned subsidiary of the buyer.

What is the cash price per share in the proposed ON24 (ONTF) acquisition?

Under the Merger Agreement, the buyer has agreed to acquire all of ON24’s outstanding common stock for $8.10 per share in cash.

How many ON24 (ONTF) shares does Indaba report owning and what percentage is that?

Indaba Capital Management, L.P., IC GP, LLC and Derek C. Schrier each report beneficial ownership of 4,240,256 shares of ON24 common stock, representing 10.0% of the class. The percentage is based on 42,282,395 shares outstanding as of November 3, 2025, as reported in ON24’s Form 10-Q.

What has Indaba agreed to do regarding its ON24 (ONTF) shares in connection with the merger?

Indaba entered into a Voting and Support Agreement with the buyer. Under this agreement, Indaba agreed to vote or cause to be voted all of its ON24 shares in favor of the merger and related transactions, and, before the Expiration Time and subject to limited exceptions, agreed not to sell or otherwise transfer its ON24 shares without the buyer’s consent.

Under what circumstances can the ON24 (ONTF) Voting and Support Agreement terminate?

The Voting and Support Agreement may terminate in certain circumstances, including upon a Company Adverse Recommendation Change, as defined in the Merger Agreement, and by written consent of the buyer (Parent), ON24 and each stockholder party to the agreement.

What additional document related to ON24 (ONTF) is referenced in connection with the merger terms?

The merger terms are described in more detail in a Form 8-K filed by ON24 with the SEC on December 30, 2025. The full text of the Voting and Support Agreement is attached as Exhibit 99.1 to this Schedule 13D/A amendment.