Churchill Capital Corp IX Ordinary Shares (CCIX) SC 13G Churchill Capital Corp IX/Cayman / Magnetar Financial ownership change

EXHIBIT 99.1

JOINT FILING AGREEMENT

The undersigned hereby agree that the statement on Schedule 13G with respect to the Shares of CHURCHILL CAPITAL CORP IX dated as of September 30, 2024 is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the previsions of Rule13d-1(k) under the Securities Exchange Act of 1934, as amended.

Date: November 6, 2024	magnetar financial llc
	By: Magnetar Capital Partners LP, its Sole Member
	By:	/s/ Hayley Stein
	Name:	Hayley Stein
	Title:   Attorney-in-fact for David J. Snyderman, Manager of Supernova Management LLC
Date: November 6, 2024	magnetar capital partners LP
	By:     Supernova Management LLC, its General Partner
	By:	/s/ Hayley Stein
	Name:	Hayley Stein
	Title:   Attorney-in-fact for David J. Snyderman, Manager of Supernova Management LLC
Date: November 6, 2024	supernova management llc
	By:	/s/ Hayley Stein
	Name:	Hayley Stein
	Title:   Attorney-in-fact for David J. Snyderman, Manager
Date: November 6, 2024	DAVID J. SNYDERMAN
	By:	/s/ Hayley Stein
	Name:	Hayley Stein
	Title:   Attorney-in-fact for David J. Snyderman