Limited Partnership Agreement of Apollo Principal Holdings VI, L.P.



 Exhibit 10.21 
 AGREEMENT OF LIMITED PARTNERSHIP 
 OF 
 APOLLO PRINCIPAL HOLDINGS VI, L.P. 
 This Agreement of Limited Partnership (this
“Agreement”) of Apollo Principal Holdings VI, L.P., a Delaware limited partnership, is made as of August 20, 2008. 
 1. The undersigned agree to form a limited partnership (the “Partnership”) under the Delaware Revised Uniform Limited Partnership Act (the “Act”) pursuant to this Agreement and the Certificate
of Limited Partnership which was filed with the Secretary of State of the State of Delaware on the date hereof in connection with the execution of this Agreement. 
 2. The Partnership is being formed for the object and purpose of, and the nature of the business to be conducted and promoted by the Partnership is, engaging in any lawful act or activity for which limited
partnerships may be formed under the Act and engaging in any and all activities necessary or incidental to the foregoing. 
 3. The general
partner of the Partnership is Apollo Principal Holdings VI GP, LLC, a Delaware limited liability company (the “General Partner”). The limited partners are AP Professional Holdings, L.P., a Cayman Islands exempted limited
partnership and APO Corp., a Delaware corporation (each a “Limited Partner” and collectively the “Limited Partners” and together with the General Partner, the “Partners”).

 4. The Partners hereby agree that the Partnership, acting by the General Partner on its behalf, without the consent or approval of the
Limited Partners, shall and is hereby authorized to enter into any agreements, deeds, receipts, certificates, filings and other documents on behalf of the Partnership, but such authorization shall not be deemed a restriction on the power of the
General Partner to take any other action on behalf of the Partnership. The Partners agree that any prior acts of the General Partner consistent with the foregoing authorizations are hereby ratified and confirmed. The General Partner and any
Authorized Person is hereby authorized to open one or more bank accounts in the name of the Partnership in such banks and trust companies as he or she may elect. The General Partner and any Authorized Person is authorized to prepare, execute and
deliver in the name and on behalf of the Partnership such designations, applications, certificates or other documents or instruments as may be necessary to open such bank account or bank accounts. Each of the following persons is hereby designed by
the General Partner as an “Authorized Person”: John J. Suydam, Tom Doria, Laurie D. Medley, Tony Tororelli and Wendy F. Dulman. 
 5. The amount and timing of all capital contributions will be as mutually agreed by all Partners. 
 6. Profits, losses and
distributions will be allocated pro rata among the Partners in proportion to their capital contributions. 







 7. No Limited Partner shall have the right to transfer any portion of its interest in the Partnership
except with the consent of the General Partner. 
 8. The Partnership shall dissolve and commence winding up in accordance with § 17-801
of the Act. 
 9. The Partners intend to replace this Agreement in due course with a definitive partnership agreement. Such action, as well
as any interim amendments to this Agreement, will require a unanimous vote of Partners. Any change in the membership of the Partnership shall require a majority vote of Partners, voting in proportion to their respective capital contributions.
Pending any replacement or amendment of this Agreement, the Partners intend the provisions of the Act to be controlling as to any matters not set forth in this Agreement. 
 10. The Partnership shall maintain its principal office at One Manhattanville Road, Suite 201, Purchase, New York 10577 or at such other place as the General Partner may determine. 
 11. This Agreement, and the rights of the Partners hereunder, shall be governed by and construed in accordance with the laws of the State of Delaware,
without regard to principles of conflict of laws. 
  

 2 








 IN WITNESS WHEREOF, the undersigned, intending to be legally bound hereby, have duly executed this
Agreement as of the day first above written. 
  

			
	General Partner:
	
	Apollo Principal Holdings VI GP, LLC
		
	By:	 	 /s/ Laurie D. Medley

	Name:	 	Laurie D. Medley
	Title:	 	Authorized Parson
	
	Limited Partners:
	
	APO Corp.
		
	By:	 	 /s/ John J. Suydam

	Name:	 	John J. Suydam
	Title:	 	Vice President
	
	AP Professional Holdings, L.P.
		
	By:	 	BRH Holdings GP, Ltd.,
		 	its general partner
		
	By:	 	 /s/ John J. Suydam

	Name:	 	John J. Suydam
	Title:	 	Vice President


 Apollo Principal Holdings VI, L.P. 
 Agreement of Limited Partnership 
 Signature Page