Assumption Agreement


 Exhibit 10.5 
 Assumption Agreement 
 ASSUMPTION AGREEMENT, dated as
of December 18, 2009, made by R.E. GAS DEVELOPMENT, LLC, a Delaware limited liability company (the “Additional Grantor”), in favor of KeyBank National Association, as administrative agent (in such capacity, the
“Administrative Agent”) for the Lenders party to the Credit Agreement referred to below. All capitalized terms not defined herein shall have the meaning ascribed to them in the Guaranty and Collateral Agreement referred to below.

 W I T N E S E T H: 
 WHEREAS, Rex Energy Corporation, a corporation duly formed and existing under the laws of the State of Delaware (the “Borrower”), the Administrative Agent, and certain financial
institutions (the “Lenders”) have entered into that certain Credit Agreement, dated as of September 28, 2007 (as amended, restated, supplemented or otherwise modified from time to time, the “Credit Agreement”);

 WHEREAS, in connection with the Credit Agreement, the Borrower and certain of its affiliates (other than the Additional
Grantor) have entered into that certain Guaranty and Collateral Agreement, dated as of September 28, 2007 (as amended, restated, supplemented or otherwise modified from time to time, the “Guaranty and Collateral Agreement”) in
favor of the Administrative Agent for the ratable benefit of the Secured Parties; 
 WHEREAS, the Credit Agreement requires the
Additional Grantor to become a party to the Guaranty and Collateral Agreement; and 
 WHEREAS, the Additional Grantor has agreed
to execute and deliver this Assumption Agreement in order to become a party to the Guaranty and Collateral Agreement; 
 NOW,
THEREFORE, IT IS AGREED: 
 1. Guaranty and Collateral Agreement. By executing and delivering this Assumption Agreement,
the Additional Grantor, as provided in Section 9.13 of the Guaranty and Collateral Agreement, hereby becomes a party to the Guaranty and Collateral Agreement as a Grantor thereunder with the same force and effect as if originally named therein
as a Grantor and, without limiting the generality of the foregoing, hereby expressly assumes all obligations and liabilities of a Grantor and a Guarantor thereunder. The information set forth in Annex 1-A hereto is hereby added to the information
set forth in the Schedules to the Guaranty and Collateral Agreement. The Additional Grantor hereby represents and warrants that, with respect to itself and as applicable, each of the representations and warranties contained in Article IV of the
Guaranty and Collateral Agreement is true and correct on and as the date hereof (after giving effect to this Assumption Agreement) as if made on and as of such date. 






 2. Governing Law. This Assumption Agreement shall be governed by, and construed in
accordance with, the laws of the State of Texas. 
 3. Miscellaneous. This Assumption Agreement may be executed in
counterparts (and by different parties hereto on different counterparts), each of which shall constitute an original, but all of which when taken together shall constitute a single contract. Any provision of this Assumption Agreement held to be
invalid, illegal or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such invalidity, illegality or unenforceability without affecting the validity, legality and enforceability of the remaining
provisions hereof; and the invalidity of a particular provision in a particular jurisdiction shall not invalidate such provision in any other jurisdiction. 
 IN WITNESS WHEREOF, the undersigned has caused this Assumption Agreement to be duly executed and delivered as of the date first above written. 
  

			
	R.E. GAS DEVELOPMENT, LLC
		
	By:	 	/s/ Benjamin W. Hulburt
	Name:	 	Benjamin W. Hulburt
	Title:	 	President and Chief Executive Officer








 ANNEX 1-A 
 NOTICE ADDRESSES OF GRANTOR 
  

			
	 Grantor
	 	 Notice Address

		
	 R.E. Gas Development, LLC
	 	 R.E. Gas Development, LLC
 c/o Rex Energy Corporation
 476 Rolling Ridge Drive, Suite 300
 State College, PA 16801
 Attn: Thomas Stabley, Chief Financial Officer
 Fax No. 814.278.7286


 INVESTMENT PROPERTY 
 Description of Pledged Securities 
  

													
	 Owner/Grantor
	  	 Issuer
	  	Percentage
Owned	  	Percentage
Pledged	  	Class of
Stock or other
Equity Interest	  	No. of
Shares	  	Certificate
No.
	 None
	  		  		  		  		  		  	

 Description of Pledged Notes 
 None. 
 FILINGS AND
OTHER ACTIONS 
 REQUIRED TO PERFECT SECURITY INTERESTS 
 Uniform Commercial Code Filings 
  

	 	1.	None 

 Description of Commercial
Tort Claims With An Asserted Value in Excess of $1,000,000 
 None. 
  






 JURISDICTION OF ORGANIZATION AND CHIEF EXECUTIVE OFFICE 
  

													
	 Legal Name/Address
	  	Trade Names
Used in Past
5 Years	  	Current
Jurisdiction of
Organization	  	Jurisdiction of
Organizations in
Past 5 Years	  	Organizational
No.	  	Taxpayer
Identification
No.	  	 Chief Executive Office or Sole
Place of
Business
over the last 5 years

	 R. E. Gas Development, LLC
 1975 Waddle Road
 State College, PA 16803
	  	None	  	Delaware	  	Not Applicable	  		  	20-8814402	  	 476 Rolling Ridge Drive, Suite 300
 State College, PA 16801


 LOCATIONS OF INVENTORY AND EQUIPMENT 
  

			
	 Grantor
	 	 Locations

	 R. E. Gas Development, LLC
	 	 1. 476 Rolling Ridge Drive, Suite 300 State College, PA 16801
  
 2. 400 Southpointe Blvd, Suite 410, Canonsburg, Pennsylvania 15317


 INTELLECTUAL PROPERTY 
 Copyrights and Copyright Licenses 
 None. 
 Patents and Patent Licenses 
 None. 
 Trademarks and Trademark Licenses 
 None. 
  
 RECEIVABLES WITH GOVERNMENTAL AUTHORITY AS OBLIGOR 
 None.