Company: CCIXW
Filing Date: 2025-12-05
Form Type: S-4/A
Source: 0001193125-25-309933
Chunk: 1021

Company: Churchill Capital Corp IX/Cayman
Filing Date: 2025-12-05
Form: S-4/A
Chunk 1021
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, and (b) such Joining Company Shareholder will be treated as a Party (with the same rights and obligations as other Company Shareholders party thereto and, if applicable, the other Insiders party thereto) for all purposes of the Amended and Restated Registration Rights Agreement.

Section 3.Notice. Any notice, demand or other communication under the Amended and Restated Registration Rights Agreement to Joining Company Shareholder shall be given to Joining Company Shareholder at the address set forth on the signature page hereto in accordance with Section 4.6‎ of the A&R Registration Rights Agreement.

Section 4.Governing Law. This Joinder shall be governed by and construed in accordance with the law of the State of Delaware.

Section 5.Counterparts; Electronic Delivery. This Joinder may be executed and delivered in one or more counterparts, by fax, email or other electronic transmission, each of which shall be deemed an original and all of which shall be considered one and the same agreement. The words “execution,” “signed,” “signature,” “delivery,” and words of like import in or relating to this Joinder or any document to be signed in connection with this Joinder shall be deemed to include electronic signatures, deliveries or the keeping of records in electronic form, each of which shall be of the same legal effect, validity or enforceability as a manually executed signature, physical delivery thereof or the use of a paper-based recordkeeping system, as the case may be, and the parties hereto consent to conduct the transactions contemplated hereunder by electronic means.

<div align='center'>(signature page follows)</div>

IN WITNESS WHEREOF, this Joinder has been duly executed and delivered by the parties as of the date first above written.

| JOINING COMPANY STOCKHOLDER: |        |
| [____]                       |        |
| By:                          |        |
| Name:                        | [____] |
| Title:                       | [____] |

| Email: |

| Mailing Address: |

<div align='center'>Signature Page to Joinder to Amended and Restated Registration Rights Agreement

Exhibit B

Form of Joinder</div>

This Joinder (this “Joinder”) to the A&R Registration Rights Agreement, made as of ___________, is between ___________ (“Transferor”) and ___________ (“Transferee”).

WHEREAS, as of the date hereof, Transferee is acquiring Registrable Securities (the “Acquired Interests”) from