Commitment Increase Agreement



 Exhibit 4.5.1 
 COMMITMENT INCREASE AGREEMENT 
 This COMMITMENT INCREASE AGREEMENT (this
“Agreement”) is made as of the 1st day of September, 2006 by and among Chesapeake Exploration
Limited Partnership, an Oklahoma limited partnership and Chesapeake Appalachia, L.L.C., an Oklahoma limited liability company (“Co-Borrowers”), Chesapeake Energy Corporation, an Oklahoma corporation (the “Company”),
Union Bank of California, N.A., as administrative agent (“Administrative Agent”), Union Bank of California, N.A. and BNP Paribas, as Issuing Lenders (“Issuing Lenders”), and the Lenders listed on the attached
Exhibit A (each a “Supplemental Lender”, and together the “Supplemental Lenders”). 
 1.
Co-Borrowers, the Company, Administrative Agent and certain Lenders, as defined therein, are parties to that certain Sixth Amended and Restated Credit Agreement dated as of February 3, 2006 (as amended, supplemented, or restated, the
“Credit Agreement”). All terms used herein and not otherwise defined shall have the same meaning given to them in the Credit Agreement. 
 2. Pursuant to Section 2.15 of the Credit Agreement, Co-Borrowers have the right to increase the Total Revolving Commitments by obtaining increases in Revolving Commitments of existing Lenders or
additional Revolving Commitments from new Lenders, upon satisfaction of certain conditions. This Agreement requires only the signature of Co-Borrowers, Administrative Agent and the Supplemental Lenders so long as the Total Revolving Commitments are
not increased above the amount permitted by Section 2.15 of the Credit Agreement. 
 3. The Supplemental Lenders are each either
(a) an existing Lender which is increasing its Revolving Commitment or (b) a new Lender which is a lending institution whose identity Co-Borrowers, Administrative Agent and Issuing Lenders hereby approve by their signatures below.

 4. In consideration of the foregoing, each Supplemental Lender, from and after the date hereof, shall have the Revolving Commitment listed
next to its name on the attached Exhibit A, which, in the case of any existing Lender, shall replace the prior Revolving Commitment of such Lender in effect immediately prior to this Agreement, as listed next to its name on the attached
Exhibit A, and any Supplemental Lender that is a new Lender hereby assumes all of the rights and obligations of a Lender under the Credit Agreement. This Agreement shall not affect the Revolving Commitments of Lenders who are not Supplemental
Lenders. 
 5. Co-Borrowers have executed and delivered to each Supplemental Lender as of the date hereof, if requested by such Supplemental
Lender, a new or replacement Note in the form attached to the Credit Agreement as Exhibit H to evidence the new or increased Revolving Commitment of such Supplemental Lender. 
 6. Each Supplemental Lender hereby represents and warrants that it has received a copy of the Credit Agreement and such financial statements, documents
and information as it has 







 deemed appropriate to make its own credit analysis and decision to enter into this Agreement, on the basis of which it
has made such analysis and decision independently and without reliance on Administrative Agent, Issuing Lenders or any other Lender. Each Supplemental Lender agrees that (1) it will, independently and without reliance on Administrative Agent,
Issuing Lenders or any other Lender, and based on such documents and information as it shall deem appropriate at the time, continue to make its own credit decisions in taking or not taking action under the Loan Documents, and (2) it will
perform in accordance with their terms all of the obligations which by the terms of the Loan Documents are required to be performed by it as a Lender. 
 7. On the effective date hereof, each Supplemental Lender shall make a Revolving Loan to Co-Borrowers to implement the provisions of Section 2.15 of the Credit Agreement. 
 8. This Agreement may not be amended, changed, waived or modified, except by a writing executed by the parties hereto. This Agreement, together with the
Loan Documents, embodies the entire agreement among each Supplemental Lender, Co-Borrowers, the Company, Administrative Agent and Issuing Lenders with respect to the subject matter hereof and supersedes all other prior arrangements and
understandings relating to the subject matter hereof. 
 9. This Agreement may be executed in any number of counterparts, each of which shall
be deemed to be an original. Each such counterpart shall become effective when counterparts have been executed by all parties hereto. Delivery of an executed counterpart of this Agreement by facsimile transmission shall be effective as delivery of a
manually executed counterpart of this Agreement. 
 This Agreement shall be governed by, and construed in accordance with, the laws governing
the Credit Agreement. 
 [Remainder of page intentionally left blank. Signature pages follow.] 
  

 2 








 IN WITNESS WHEREOF, Administrative Agent, Co-Borrowers, the Company and the Supplemental Lenders have
executed this Agreement as of the date shown above. 
  

					
	CHESAPEAKE EXPLORATION LIMITED PARTNERSHIP
		
	By:	 	Chesapeake Operating, Inc., its general partner
			
		 	By:	 	 /s/ MARTHA A. BURGER

		 		 	Martha A. Burger
		 		 	Treasurer and Senior Vice President
		 		 	– Human Resources
	
	CHESAPEAKE APPALACHIA, L.L.C.
		
	By:	 	 /s/ MARTHA A. BURGER

		 	Martha A. Burger
		 	Treasurer and Senior Vice President
		 	– Human Resources
	
	CHESAPEAKE ENERGY CORPORATION
		
	By:	 	 /s/ MARTHA A. BURGER

		 	Martha A. Burger
		 	Treasurer and Senior Vice President
		 	– Human Resources










			
	UNION BANK OF CALIFORNIA, N.A.,
	as Administrative Agent and Issuing Lender
		
	By:	 	 /s/ RANDALL L. OSTERBERG

	Name:	 	Randall L. Osterberg
	Title:	 	Sr. Vice President – US Marketing Mgr.










			
	BNP PARIBAS, as Issuing Lender
		
	By:	 	 /s/ DAVID DODD

	Name:	 	David Dodd
	Title:	 	Director
		
	By:	 	 /s/ ROBERT LONG

	Name:	 	Robert Long
	Title:	 	Vice President










			
	BANK OF AMERICA, N.A.,
	as Supplemental Lender
		
	By:	 	 /s/ RONALD E. McKAIG

	Name:	 	Ronald E. McKaig
	Title:	 	Senior Vice President










			
	CALYON NEW YORK BRANCH,
	as Supplemental Lender
		
	By:	 	 /s/ MICHAEL D. WILLIS

	Name:	 	Michael D. Willis
	Title:	 	Director
		
	By:	 	 /s/ DENNIS E. PETITO

	Name:	 	Dennis E. Petito
	Title:	 	Managing Director










			
	SUNTRUST BANK, as Supplemental Lender
		
	By:	 	 /s/ SEAN M. ROCHE

	Name:	 	Sean M. Roche
	Title:	 	Vice President










			
	FORTIS CAPITAL CORP., as Supplemental Lender
		
	By:	 	 /s/ DARRELL HOLLEY

	Name:	 	Darrell Holley
	Title:	 	Managing Director
		
	By:	 	 /s/ CASEY LOWARY

	Name:	 	Casey Lowary
	Title:	 	Senior Vice President










			
	 WACHOVIA BANK NATIONAL ASSOCIATION,
 as
Supplemental Lender

		
	By:	 	 /s/ JAY BUCKMAN

	Name:	 	Jay Buckman
	Title:	 	Vice President










			
	 THE ROYAL BANK OF SCOTLAND plc, as
 Supplemental Lender

		
	By:	 	 /s/ SCOTT L. JOYCE

	Name:	 	Scott L. Joyce
	Title:	 	Vice President










			
	WELLS FARGO BANK, N.A., as Supplemental Lender
		
	By:	 	 /s/ DUSTIN S. HANSEN

	Name:	 	Dustin S. Hansen
	Title:	 	Vice President










			
	BANK OF SCOTLAND, as Supplemental Lender
		
	By:	 	 /s/ KAREN WEICH

	Name:	 	Karen Weich
	Title:	 	Assistant Vice President










			
	 BMO CAPITAL MARKETS FINANCING, INC.,
 as
Supplemental Lender

		
	By:	 	 /S/ MARY LOU ALLEN

	Name:	 	Mary Lou Allen
	Title:	 	Vice President










			
	BARCLAYS BANK PLC, as Supplemental Lender
		
	By:	 	 /s/ NICHOLAS BELL

	Name:	 	Nicholas Bell
	Title:	 	Director










			
	ABN AMRO BANK N.V. , as Supplemental Lender
		
	By:	 	 /s/ JOSHUA WOLF

	Name:	 	Joshua Wolf
	Title:	 	Vice President
		
	By:	 	 /s/ JIM MOYES

	Name:	 	Jim Moyes
	Title:	 	Managing Director










			
	COMERICA BANK, as Supplemental Lender
		
	By:	 	 /s/ PETER L. SEFZIK

	Name:	 	Peter L. Sefzik
	Title:	 	Vice President










			
	ROYAL BANK OF CANADA, as Supplemental Lender
		
	By:	 	 /s/ DON J. McKINNERNEY

	Name:	 	Don J. McKinnerney
	Title:	 	Authorized Signatory










			
	 TORONTO DOMINION (TEXAS) LLC, as
 Supplemental Lender

		
	By:	 	 /s/ JACKIE BARRETT

	Name:	 	Jackie Barrett
	Title:	 	Authorized Signatory










			
	 BAYERISCHE HYPO-UND VEREINSBANK AG
 - NEW
YORK BRANCH, as Supplemental Lender

		
	By:	 	 /s/ ANDREW MATTHEWS

	Name:	 	Andrew Mathews
	Title:	 	Managing Director
		
	By:	 	 /s/ ROGER G. EUSTANCE

	Name:	 	Roger G. Eustance
	Title:	 	Director










			
	RZB FINANCE LLC, as Supplemental Lender
		
	By:	 	 /s/ HERMINE KIROLOS

	Name:	 	Hermine Kirolos
	Title:	 	Group Vice President
		
	By:	 	 /s/ PEARL GEFFERS

	Name:	 	Pearl Geffers
	Title:	 	First Vice President










			
	 DZ BANK AG DEUTSCHE ZENTRAL -
 GENOSSENSCHRAFTBANK FRANKFURT AM
 MAIN, NEW YORK BRANCH, as Supplemental
 Lender

		
	By:	 	 /s/ WILLIAM G. ROOS

	Name:	 	William G. Roos
	Title:	 	Senior Vice President
		
	By:	 	 /s/ DARIA A. PIAHKO

	Name:	 	Daria A. Piahko
	Title:	 	First Vice President










			
	WESTLB AG, NY BRANCH, as Supplemental Lender
		
	By:	 	 /s/ THOMAS D. MURRAY

	Name:	 	Thomas D. Murray
	Title:	 	Managing Director
		
	By:	 	 /s/ PAUL VASTOLA

	Name:	 	Paul Vastola
	Title:	 	Director










			
	MIDFIRST BANK, as Supplemental Lender
		
	By:	 	 /s/ STEVE A. GRIFFIN

	Name:	 	Steve A. Griffin
	Title:	 	Senior Vice President










			
	MORGAN STANLEY BANK, as Supplemental Lender
		
	By:	 	 /s/ DANIEL TWENGE

	Name:	 	Daniel Twenge
	Title:	 	Authorized Signatory










			
	 BEAR STEARNS CORPORATE LENDING INC. ,
 as
Supplemental Lender

		
	By:	 	 /s/ LINDA A. CARPER

	Name:	 	Linda A. Carper
	Title:	 	Vice President










			
	 CREDIT SUISSE, CAYMAN ISLANDS BRANCH,
 as
Supplemental Lender

		
	By:	 	 /s/ DAVID DODD

	Name:	 	David Dodd
	Title:	 	Vice President
		
	By:	 	 /s/ SHAHEEN MALIK

	Name:	 	Shaheen Malik
	Title:	 	Associate










			
	UBS LOAN FINANCE LLC, as Supplemental Lender
		
	By:	 	 /s/ RICHARD L. TAVROW

	Name:	 	Richard L. Tavrow
	Title:	 	Director
		
	By:	 	 /s/ IRJA R. Olsa

	Name:	 	Irja R. Olsa
	Title:	 	Associate Director










			
	 DEUTSCHE BANK TRUST COMPANY
 AMERICAS, as
Supplemental Lender

		
	By:	 	 /s/ SAAD IQBAL

	Name:	 	Saad Iqbal
	Title:	 	Vice President
		
	By:	 	 /s/ EVELYN THIERRY

	Name:	 	Evelyn Thierry
	Title:	 	Vice President










			
	 GOLDMAN SACHS CREDIT PARTNERS, L.P.,
 as
Supplemental Lender

		
	By:	 	 /s/ WILLIAM ARCHER

	Name:	 	William Archer
	Title:	 	Managing Director










			
	 LEHMAN COMMERCIAL PAPER INC., as
 Supplemental Lender

		
	By:	 	 /s/ DIANE ALBANESE

	Name:	 	Diane Albanese
	Title:	 	Authorized Signatory









 Exhibit A 
  

							
	 Supplemental Lender
	  	 Prior
 Revolving
Commitment
	  	New Revolving
Commitment
	 Bank of America, N.A.
	  	$	125,000,000	  	$	150,000,000
	 Calyon New York Branch
	  	$	125,000,000	  	$	150,000,000
	 SunTrust Bank
	  	$	125,000,000	  	$	150,000,000
	 Fortis Capital Corp.
	  	$	125,000,000	  	$	150,000,000
	 Wachovia Bank National Association
	  	$	100,000,000	  	$	125,000,000
	 Royal Bank of Scotland
	  	$	100,000,000	  	$	150,000,000
	 Wells Fargo Bank, N.A.
	  	$	100,000,000	  	$	125,000,000
	 Bank of Scotland
	  	$	100,000,000	  	$	125,000,000
	 BMO Capital Markets Financing, Inc.
	  	$	65,000,000	  	$	100,000,000
	 Barclays Bank PLC
	  	$	40,000,000	  	$	55,000,000
	 ABN AMRO Bank N.V.
	  	$	40,000,000	  	$	65,000,000
	 Comerica Bank
	  	$	50,000,000	  	$	100,000,000
	 Royal Bank of Canada
	  	$	45,000,000	  	$	50,000,000
	 Toronto Dominion (Texas) LLC
	  	$	35,000,000	  	$	50,000,000
	 Bayerische Hypo-und Vereinsbank AG – New York Branch
	  	$	30,000,000	  	$	50,000,000
	 RZB Finance LLC
	  	$	30,000,000	  	$	40,000,000
	 DZ Bank AG Deutsche Zentral – Genossenschraftbank Frankfurt am Main, New York Branch
	  	$	30,000,000	  	$	35,000,000
	 WestLB AG, NY Branch
	  	$	30,000,000	  	$	50,000,000
	 MidFirst Bank
	  	$	30,000,000	  	$	35,000,000
	 Morgan Stanley Bank
	  	$	10,000,000	  	$	20,000,000
	 Bear Stearns Corporate Lending Inc.
	  	$	10,000,000	  	$	20,000,000
	 Credit Suisse, Cayman Islands Branch
	  	$	10,000,000	  	$	20,000,000
	 UBS Loan Finance LLC
	  	$	10,000,000	  	$	20,000,000
	 Deutsche Bank Trust Company Americas
	  	$	10,000,000	  	$	20,000,000
	 Goldman Sachs Credit Partners, L.P.
	  	$	10,000,000	  	$	20,000,000
	 Lehman Commercial Paper Inc.
	  	$	10,000,000	  	$	20,000,000
		  	 	 	  	 	 
	 Increase in Total Revolving Commitments
	  	 	$500,000,000