exhibit4_a3.htm


    
      
        

      
EXHIBIT 4.A.3

     

    Execution
Copy

     

    


     

    COLORADO INTERSTATE GAS
COMPANY

     

    


     

    as Issuer

     

    


     

    and

     

    


     

    THE BANK OF NEW YORK TRUST COMPANY,
N.A.

     

    


     

    as Trustee

     

    


     

    THIRD SUPPLEMENTAL
INDENTURE

     

    


     

    Dated as of November 1,
2005

     

    


     

    To

     

    INDENTURE

     

    Dated as of June 27,
1997

     

    


     

    6.80% SENIOR NOTES DUE 2015

     

    


     

    


     

    


     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    
 

    
TABLE
OF CONTENTS

     

     

    Page

     

    
      	
              ARTICLE 1
      Relation to Indenture; Definitions

            	
              1

            
	 	
              SECTION
      1.01.

            	
              Relation to
      Indenture 

            	
              1

            
	 	
              SECTION
      1.02.

            	
              Definitions

            	
              1

            
	 	
              SECTION
      1.03.

            	
              General
      References

            	
              1

            
	 	 	 	 
	
              ARTICLE
      2 The Series
      of Securities

            	
              2

            
	 	
              SECTION
      2.01.

            	
              The Form and
      Title of the Securities

            	
              2

            
	 	
              SECTION
      2.02.

            	
              Amount

            	
              2

            
	 	
              SECTION
      2.03.

            	
              Stated
      Maturity

            	
              2

            
	 	
              SECTION
      2.04.

            	
              Interest and
      Interest Rates

            	
              2

            
	 	
              SECTION
      2.05.

            	
              Place of
      Payment

            	
              2

            
	 	
              SECTION
      2.06.

            	
              Optional
      Redemption

            	
              2

            
	 	
              SECTION
      2.07.

            	
              Discharge

            	
              3

            
	 	
              SECTION
      2.08.

            	
              Global
      Securities; Restrictions on Transfer and Exchange

            	
              3

            
	 	
              SECTION
      2.09.

            	
              Transfer and
      Exchange

            	
              3

            
	 	
              SECTION
      2.10.

            	
              Legends

            	
              4

            
	 	
              SECTION
      2.11.

            	
              Registration
      Rights Agreement

            	
              5

            
	 	 
	
              ARTICLE
      3 Covenants;
      Amendments to Indenture

            	
              5

            
	 	
              SECTION
      3.01.

            	
              Additional
      Covenant

            	
              5

            
	 	
              SECTION
      3.02.

            	
              Amendments to
      Indenture

            	
              6

            
	 	 	 	 
	
              ARTICLE
      4
      Miscellaneous

            	
              7

            
	 	
              SECTION
      4.01.

            	
              Certain
      Trustee Matters

            	
              7

            
	 	
              SECTION
      4.02.

            	
              Continued
      Effect

            	
              8

            
	 	
              SECTION
      4.03.

            	
              Governing
      Law

            	
              8

            
	 	
              SECTION
      4.04.

            	
              Counterparts

            	
              8

            


    

     

     

    EXHIBITS

     

    Exhibit
A: Form of
Note

     

     

     

     

     

     

     


    
      
        
          Third
Supplemental Indenture

        

        
        

      

      
        
        

        
          

        

      

      
        
        

        
        

      

    



    THIRD
SUPPLEMENTAL INDENTURE, dated as of
November 1, 2005 (this “Third
Supplemental Indenture”), between
COLORADO
INTERSTATE GAS COMPANY, a Delaware
corporation (the “Company”), and
THE
BANK OF NEW YORK TRUST COMPANY, N.A., a national
banking association (successor-in-interest to Harris Trust and Savings Bank), as
trustee under the Indenture referred to below (in such capacity, the
“Trustee”).

     

    RECITALS
OF THE COMPANY

     

    WHEREAS, the
Company and the Trustee are parties to an Indenture, dated as of June 27, 1997
(the “Original
Indenture”), as amended and
supplemented by the First Supplemental Indenture thereto dated as of June 27,
1997 (the “First
Supplemental Indenture”), and the Second
Supplemental Indenture thereto dated as of March 9, 2005 (the “Second
Supplemental Indenture”) (the Original
Indenture, as supplemented from time to time, including without limitation
pursuant to the First Supplemental Indenture and the Second Supplemental
Indenture and pursuant to this Third Supplemental Indenture being referred to
herein as the “Indenture”);
and

     

    WHEREAS, under the
Original Indenture, a new series of Securities may at any time be established by
the Board of Directors of the Company, in accordance with the provisions of the
Original Indenture, and the terms of such series may be established by a
supplemental indenture executed by the Company and by the Trustee;
and

     

    WHEREAS, the
Company proposes to create under the Indenture a new series of Securities;
and

     

    WHEREAS, all acts
and things necessary to make the Notes (as herein defined), when executed by the
Company and authenticated and delivered by the Trustee as provided in the
Original Indenture and this Third Supplemental Indenture, the valid and binding
obligations of the Company and to make this Third Supplemental Indenture a valid
and binding agreement in accordance with the Original Indenture have been done
or performed; and

     

    WHEREAS, the
Company has entered into a Registration Rights Agreement dated as of November 1,
2005 (the “Registration
Rights Agreement”) relating to the
Notes, among the Company and the initial purchasers named therein (the
“Initial
Purchasers”);

     

    NOW, THEREFORE, in
consideration of the premises, agreements and obligations set forth herein and
for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto hereby agree, for the equal and
proportionate benefit of all Holders of the Notes, as follows:

     

    ARTICLE
1

    Relation
to Indenture; Definitions

     

    SECTION
1.01.   Relation
to Indenture. 

     

    With respect to the
Notes, this Third Supplemental Indenture constitutes an integral part of the
Indenture.

     

    SECTION
1.02.   Definitions. 

     

    For all purposes of
this Third Supplemental Indenture, capitalized terms used herein and not
otherwise defined herein shall have the meanings assigned thereto in the
Original Indenture.

     

    SECTION
1.03.   General
References. 

     

    All references in
this Third Supplemental Indenture to Articles and Sections, unless otherwise
specified, refer to the corresponding Articles and Sections of this Third
Supplemental Indenture; and the terms “herein”, “hereof”, “hereunder” and any other
word of similar import refers to this Third Supplemental
Indenture.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    ARTICLE
2

    The
Series of Securities

     

    SECTION
2.01.   The
Form and Title of the Securities. 

     

    There is hereby
established a new series of Securities to be issued under the Indenture and to
be designated as the Company’s 6.80% Senior Notes due 2015 (the “Notes”). The Notes shall
be substantially in the form attached as Exhibit A hereto, in each
case with such appropriate insertions, omissions, substitutions and other
variations as are required or permitted by the Indenture, and may have such
letters, numbers or other marks of identification and such legends or
endorsements placed thereon as the Company may deem appropriate or as may be
required or appropriate to comply with any laws or with any rules made pursuant
thereto or with the rules of any securities exchange or automated quotation
system on which the Notes may be listed or traded, or to conform to general
usage, or as may, consistently with the Indenture, be determined by the officers
executing such Notes, as evidenced by their execution
thereof.

     

    The Notes shall be
executed, authenticated and delivered in accordance with the provisions of, and
shall in all respects be subject to, the terms, conditions and covenants of the
Original Indenture as supplemented by this Third Supplemental Indenture
(including the form of Note set forth as Exhibit A hereto (the terms
of which are incorporated in and made a part of this Third Supplemental
Indenture for all intents and purposes)).

     

    SECTION
2.02.   Amount. 

     

    The aggregate
principal amount of the Notes which may be authenticated and delivered pursuant
hereto is unlimited. The Trustee shall initially authenticate and deliver Notes
for original issue in an initial aggregate principal amount of up to
$400,000,000 upon delivery to the Trustee of a Company Order for the
authentication and delivery of such Notes. The Company may, from time to time,
without notice to or the consent of the Holders of the Notes, increase the
principal amount of the Notes under the Indenture and issue such increased
principal amount (or any portion thereof), in which case any additional Notes so
issued will have the same form and terms (other than the date of issuance and,
under certain circumstances, the date from which interest thereon will begin to
accrue), and will carry the same right to receive accrued and unpaid interest,
as the Notes previously issued, and such additional Notes will form a single
series with the Notes previously issued.

     

    SECTION
2.03.   Stated
Maturity.

     

    The Notes may be
issued on any Business Day on or after November 1, 2005, and the Stated Maturity
of the Notes shall be November 15, 2015.

     

    SECTION
2.04.   Interest
and Interest Rates. 

     

    The rate or rates
at which the Notes shall bear interest, the date or dates from which such
interest shall accrue, the Interest Payment Dates on which any such interest
shall be payable and the Regular Record Date for any interest payable on any
Interest Payment Date, in each case, shall be as set forth in the form of Note
set forth as Exhibit A
hereto.

     

    SECTION
2.05.   Place
of Payment. 

     

    As long as any
Notes are outstanding, the Company shall maintain an office or agency in the
Borough of Manhattan, The City of New York, where Notes may be presented for
payment.

     

    SECTION
2.06.   Optional
Redemption.

     

    At its option, the
Company may redeem the Notes, in whole or in part, in principal amounts of
$1,000 or any integral multiple thereof, at any time or from time to time, at
the applicable redemption price determined as set forth in the form of Note
attached hereto as Exhibit
A, in accordance
with the terms set forth in the Notes and in accordance with Article 3A of the
Original Indenture.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    SECTION
2.07.   Discharge.

     

    Article 8 of the
Original Indenture shall apply to the Notes.

     

    SECTION
2.08.   Global
Securities; Restrictions on Transfer and Exchange. 

     

    The Notes shall
initially be issued in the form of one or more Global Securities. Such Global
Securities (i)  shall bear the legends applicable to Global Securities set
forth in the Original Indenture (including without limitation in Section 2.03
thereof), (ii) may be exchanged in whole or in part for Securities in
definitive form upon the terms and subject to the conditions provided in
Section 2.07 of the Original Indenture and in this Third Supplemental
Indenture and (iii) shall otherwise be subject to the applicable provisions
of the Indenture.

     

    (1)  Rule
144A Global Notes. The Notes offered
and sold to “qualified institutional buyers” (“QIBs” or individually,
a “QIB”) (which term
shall have the meaning assigned to it in Rule 144A under the Securities Act of
1933, as amended (the “Securities
Act”)) in the United
States of America in reliance on Rule 144A will initially be issued as permanent
Global Securities (the “Rule
144A Global Notes”), without
interest coupons, substantially in the form of Exhibit
A hereto. The Rule
144A Global Notes will be duly executed by the Company, authenticated by the
Trustee, deposited with the Trustee (as custodian for The Depository Trust
Company (“DTC”), which shall act
as Depository with respect to the Notes constituting Global Securities) and
registered in the name of DTC or a nominee thereof.

     

    (2)  Regulation
S Global Notes. Notes offered and
sold in Offshore Transactions to Non-U.S. Persons (each such term to have the
meaning assigned to it in Regulation S under the Securities Act (“Regulation
S”)) in reliance on
Regulation S will initially be issued as permanent Global Securities (the
“Regulation
S Global Notes”), without
interest coupons, substantially in the form of Exhibit
A hereto. The
Regulation S Global Notes will be duly executed by the Company, authenticated by
the Trustee, deposited with the Trustee (as custodian for DTC) and registered in
the name of DTC or a nominee thereof.

     

    SECTION
2.09.   Transfer
and Exchange. 

     

    (1)  Transfer
and Exchange of Notes in Certificated Form. In addition to
the requirements set forth in Section 2.07 of the Original Indenture, the Notes
in certificated form that are Registrable Securities under the Registration
Rights Agreement (the “Transfer
Restricted Securities”) presented or
surrendered for registration of transfer or exchange pursuant to Section 2.07 of
the Original Indenture shall be accompanied by the following additional
information and documents, as applicable, upon which the Registrar may
conclusively rely:

     

    (a)  if such Transfer
Restricted Securities are being delivered to the Registrar by a Holder for
registration in the name of such Holder, without transfer, a certification from
such Holder to that effect (in substantially the form of the Exchange/Transfer
Certificate included in Exhibit
A hereto);
or

     

    (b)  if such Transfer
Restricted Securities are being transferred (1) to a QIB in accordance with Rule
144A under the Securities Act or (2) pursuant to an exemption from registration
in accordance with Rule 144 under the Securities Act (and based upon an opinion
of counsel if the Company or the Trustee so requests) or (3) pursuant to an
effective registration statement under the Securities Act, a certification to
that effect from such holder (in substantially the form of the Exchange/Transfer
Certificate included in Exhibit
A hereto);
or

     

    (c)  if such Transfer
Restricted Securities are being transferred pursuant to an exemption from
registration in accordance with Rule 904 of Regulation S under the Securities
Act, certifications to that effect from such Holder (in substantially the form
of both (i) the Exchange/Transfer Certificate included in Exhibit
A hereto and (ii)
the Regulation S Certificate included in Exhibit
A hereto) and an
opinion of counsel to that effect if the Company or the Trustee so requests;
or

     

    (d)  if such Transfer
Restricted Securities are being transferred in reliance on and in compliance
with another exemption from the registration requirements of the Securities Act,
a certification to that effect from such Holder (in substantially the form of
the Exchange/Transfer Certificate included in Exhibit
A hereto) and an
opinion of counsel to that effect if the Company or the Trustee so
requests.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    (2)  Transfer
and Exchange of Global Notes. The transfer and
exchange of the Global Notes (as defined below) or beneficial interests therein
shall be effected through the Depository, upon the terms and subject to the
conditions provided in Section 2.07 of the Original Indenture and Article 2 of
this Third Supplemental Indenture (including the restrictions on transfer set
forth therein and herein) and the rules and procedures of the Depository
therefor, which shall include restrictions on transfer comparable to those set
forth therein and herein to the extent required by the Securities
Act.

     

    SECTION
2.10.   Legends. 

     

    (1)  Except as permitted
by the following paragraphs (2) and (3) immediately below, each certificate
evidencing the Rule 144A Global Notes or Regulation S Global Notes (each a
“Global
Note”) or any other
Notes in certificated form (and all Notes issued in exchange therefor or
substitution thereof other than the Exchange Notes (as defined below)) shall
bear a legend in substantially the following form:

     

    THIS NOTE HAS NOT
BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE
“SECURITIES ACT”) AND, ACCORDINGLY, MAY NOT BE OFFERED, SOLD, PLEDGED OR
OTHERWISE TRANSFERRED WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
BENEFIT OF, U.S. PERSONS, EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS
ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE HOLDER (1) REPRESENTS
THAT (A) IT IS A “QUALIFIED INSTITUTIONAL BUYER” (AS DEFINED IN RULE 144A UNDER
THE SECURITIES ACT) (A “QIB”), (B) IT IS NOT A U.S. PERSON, IS NOT ACQUIRING
THIS NOTE FOR THE ACCOUNT OR BENEFIT OF A U.S. PERSON AND IS ACQUIRING THIS NOTE
IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH REGULATION S UNDER THE SECURITIES
ACT OR (C) IT IS AN INSTITUTIONAL “ACCREDITED INVESTOR” (AS DEFINED IN RULE
501(A)(1), (2), (3) OR (7) OF REGULATION D UNDER THE SECURITIES ACT) (AN “IAI”),
(2) AGREES THAT IT WILL NOT, WITHIN THE TIME PERIOD REFERRED TO UNDER RULE
144(k) (TAKING INTO ACCOUNT THE PROVISIONS OF RULE 144(d) UNDER THE SECURITIES
ACT, IF APPLICABLE) UNDER THE SECURITIES ACT AS IN EFFECT ON THE DATE OF THE
TRANSFER OF THIS NOTE, RESELL OR OTHERWISE TRANSFER THIS NOTE EXCEPT (A) TO THE
ISSUER OR ANY SUBSIDIARY THEREOF, (B) TO A PERSON WHOM THE HOLDER REASONABLY
BELIEVES IS A QIB PURCHASING FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QIB IN
COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (C) OUTSIDE THE UNITED
STATES IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH RULE 904 UNDER THE
SECURITIES ACT, (D) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY RULE
144 UNDER THE SECURITIES ACT (IF AVAILABLE), (E) TO AN IAI THAT, PRIOR TO SUCH
TRANSFER, FURNISHES TO THE TRUSTEE A SIGNED LETTER CONTAINING CERTAIN
REPRESENTATIONS AND AGREEMENTS RELATING TO THE REGISTRATION OF TRANSFER OF THIS
NOTE (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM THE TRUSTEE) AND, IF SUCH
TRANSFER IS IN RESPECT OF AN AGGREGATE PRINCIPAL AMOUNT OF NOTES AT THE TIME OF
TRANSFER OF LESS THAN $250,000, AN OPINION OF COUNSEL ACCEPTABLE TO THE ISSUER
THAT SUCH TRANSFER IS IN COMPLIANCE WITH THE SECURITIES ACT OR (F) PURSUANT TO
AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND, IN EACH CASE,
IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS, AND (3) AGREES THAT IT WILL
DELIVER TO EACH PERSON TO WHOM THIS NOTE OR AN INTEREST HEREIN IS TRANSFERRED A
NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY
TRANSFER OF THIS NOTE OR ANY INTEREST HEREIN WITHIN THE TIME PERIOD REFERRED TO
ABOVE, THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF
RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE
TRUSTEE. AS USED HEREIN, THE TERMS “OFFSHORE TRANSACTION,”“UNITED STATES” AND
“U.S. PERSON” HAVE THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S UNDER
THE SECURITIES ACT. THE INDENTURE CONTAINS A PROVISION REQUIRING THE TRUSTEE TO
REFUSE TO REGISTER ANY TRANSFER OF THIS NOTE IN VIOLATION OF THE FOREGOING
RESTRICTIONS.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    (2)  Upon any sale or
transfer of a Transfer Restricted Security (including any Transfer Restricted
Security represented by a Global Note) pursuant to Rule 144 under the Securities
Act or an effective registration statement under the Securities Act, which
effectiveness shall be certified by the Company to the Trustee and Registrar
upon which each may conclusively rely:

     

    (a)  in the case of any
Transfer Restricted Security in definitive form, the Registrar shall permit the
Holder thereof to exchange such Transfer Restricted Security for a Note in
definitive form that does not bear the legend set forth in (1) above and rescind
any restriction on the transfer of such Transfer Restricted Security;
and

     

    (b)  in the case of any
Transfer Restricted Security represented by a Global Note, such Transfer
Restricted Security shall not be required to bear the legend(s) set forth in (1)
above if all other interests in such Global Note have been or are concurrently
being sold or transferred pursuant to Rule 144 under the Securities Act or
pursuant to an effective registration statement under the Securities Act, but
such Transfer Restricted Security shall continue to be subject to the provisions
of Section 2.07 of the Original Indenture and this Section 2.10 of this Third
Supplemental Indenture.

     

    (3)  Notwithstanding the
foregoing, upon consummation of the Exchange Offer (as defined in the
Registration Rights Agreement), the Company shall issue and, upon receipt of a
Company Order in accordance with Section 2.03 of the Original Indenture, the
Trustee shall authenticate Notes (“Exchange
Notes”) in exchange for
Notes accepted for exchange in the Exchange Offer, which Exchange Notes shall
not bear the legend set forth in (1) above, and the Registrar shall rescind any
restriction on the transfer of the Exchange Notes, in each case unless the
Holder of Notes being transferred in the Exchange Offer is either (A) a
broker-dealer tendering Notes acquired directly from the Company, (B) a person
participating in the Exchange Offer for purposes of distributing the Exchange
Notes or (C) a person who is an “affiliate” (as defined in Rule 144 under the
Securities Act) of the Company. The Company shall identify to the Trustee such
Holders of the Notes in a written certification signed by an Officer of the
Company and, absent receipt of a certificate from the Company to such effect,
the Trustee shall assume that there are no such Holders.

     

    SECTION
2.11.   Registration
Rights Agreement. 

     

    Holders of the
Notes shall have the benefit of the Company’s registration obligations with
respect to the Notes, and such Holders shall also have certain obligations to
indemnify the Company under certain circumstances, all as more fully set forth
in the Registration Rights Agreement.

     

    ARTICLE
3

    Covenants;
Amendments to Indenture

     

    SECTION
3.01.   Additional
Covenant

     

    The covenant
contained in this Section 3.01 shall apply to the Notes only and not to any
other series of Securities issued under the Indenture, and is being included
solely for the benefit of the Notes and the Holders thereof. This covenant shall
be effective only for so long as there remain outstanding any
Notes.

     

    SEC
Reports; Financial Statements. In addition to
the requirements of Section 4.05 of the Original Indenture:

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    (1) whether or not the
Company is then subject to Section 13 or 15(d) of the Exchange Act, from and
after the Original Issue Date of the Notes, the Company shall electronically
file with the SEC, so long as the Notes are outstanding, the annual, quarterly
and other periodic reports that the Company is required to file (or would
otherwise be required to file) with the SEC pursuant to Sections 13 and 15(d) of
the Exchange Act, and such documents shall be filed with the SEC on or prior to
the respective dates (the “Required
Filing Dates”) by which the
Company is required to file (or would otherwise be required to file) such
documents, unless, in each case, such filings are not then permitted by the
SEC;

     

    (2) from and after the
Original Issue Date of the Notes, the Company shall provide the Trustee with,
and the Trustee will mail to any Holder of Notes requesting in writing to the
Trustee copies of, such annual, quarterly and other periodic reports specified
in Sections 13 and 15(d) of the Exchange Act within 15 days after its Required
Filing Date;

     

    (3) in addition, for so
long as the Notes are not freely transferable under the Securities Act, the
Company shall furnish to the Holders of Notes and to prospective investors in
the Notes, the information required to be delivered pursuant to Rule 144A(d)(4)
under the Securities Act;

     

    (4) the Company shall
provide the Trustee with a sufficient number of copies of all reports and other
documents and information that the Trustee may be required to deliver to Holders
of Notes under clause (2) of this Section 3.01; and

     

    (5) delivery of such
reports, information and documents to the Trustee is for informational purposes
only and the Trustee’s receipt of such shall not constitute constructive notice
of any information contained therein or determinable from information contained
therein, including the Company’s compliance with any of its covenants hereunder
(as to which the Trustee is entitled to rely exclusively on Officers’
Certificates).

     

    SECTION
3.02.   Amendments
to Indenture

     

    The amendments
contained in this Section 3.02 shall apply to the Notes only and not to any
other series of Securities issued under the Indenture. Such amendments shall be
effective only for so long as there remain outstanding any Notes.

     

    (a) Section 1.01 of the
Original Indenture is hereby amended, subject to the preamble of this Section
3.02 and with respect to the Notes only, by inserting the following definition
in the appropriate alphabetical position:

     

    “Permitted Liens”
means

     

    (1) Liens upon
rights-of-way for pipeline purposes;

     

    (2) any governmental
Lien, mechanics’, materialmen’s, carriers’ or similar Lien incurred in the
ordinary course of business which is not yet due or which is being contested in
good faith by appropriate proceedings and any undetermined Lien which is
incidental to construction;

     

    (3) the right reserved
to, or vested in, any municipality or public authority by the terms of any
right, power, franchise, grant, license, permit or by any provision of law, to
purchase or recapture or to designate a purchase of, any
property;

     

    (4) Liens of taxes and
assessments which are (A) for the then current year, (B) not at the time
delinquent or (C) delinquent but the validity of which is being contested at the
time by the Company or any Subsidiary in good faith;

     

    (5) Liens of, or to
secure performance of leases;

     

    (6) any Lien upon, or
deposits of, any assets in favor of any surety company or clerk of court for the
purposes of obtaining indemnity or stay of judicial
proceedings;

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    (7) any Lien upon
property or assets acquired or sold by the Company or any Subsidiary resulting
from the exercise of any rights arising out of defaults on
receivables;

     

    (8) any Lien incurred
in the ordinary course of business in connection with workmen’s compensation,
unemployment insurance, temporary disability, social security, retiree health or
similar laws or regulations or to secure obligations imposed by statute or
governmental regulations;

     

    (9) any Lien upon any
property or assets in accordance with customary banking practice to secure any
Indebtedness incurred by the Company or any Subsidiary in connection with the
exporting of goods to, or between, or the marketing of goods in, or the
importing of goods from, foreign countries;

     

    (10) any Lien securing
industrial development, pollution control, or similar revenue
bonds;

     

    (11) Liens to secure
Indebtedness owing to the Company or its Subsidiaries;

     

    (12) Liens contemplated
by the Indenture relating to compensation and other payments to the Trustee;
and

     

    (13) Liens deemed to
exist by reason of negative pledges in respect of
Indebtedness.

     

    (b) Section 2.03 of the
Original Indenture is hereby amended, subject to the preamble of this Section
3.02 and with respect to the Notes only, by deleting the second sentence of the
first paragraph of such Section 2.03.

     

    (c) Section 4.08 of the
Original Indenture is hereby amended, subject to the preamble of this Section
3.02 and with respect to the Notes only, by:

     

    (i) deleting the word
“and” immediately following the semicolon appearing in clause (5) of such
Section 4.08;

     

    (ii) inserting the
following new clause (6) immediately below clause (5) of such Section
4.08:

     

    (6) Permitted Liens;
and

     

    ; and

     

    (iii) renumbering and
restating the former clause (6) of such Section 4.08 to read in its entirety as
follows:

     

    (7) any extension,
renewal or replacement (or successive extensions, renewals or replacements), as
a whole or in part, of any Lien referred to in the foregoing clauses (1) through
(6) inclusive; provided that such extension, renewal or replacement of such Lien
is limited to all or any part of the same property, shares of stock or
Indebtedness that secured the Lien extended, renewed or replaced (plus
improvements on such property), and that such secured Indebtedness at such time
is not increased.

     

    ARTICLE
4

    Miscellaneous

     

    SECTION
4.01.   Certain
Trustee Matters. 

     

    The recitals
contained herein shall be taken as the statements of the Company, and the
Trustee assumes no responsibility for their correctness.

     

    The Trustee makes
no representations as to the validity or sufficiency of this Third Supplemental
Indenture or the Notes or the proper authorization or the due execution hereof
or thereof by the Company.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    SECTION
4.02.   Continued
Effect. 

     

    Except as expressly
supplemented and amended by this Third Supplemental Indenture, the Original
Indenture (as supplemented and amended by the First Supplemental Indenture)
shall continue in full force and effect in accordance with the provisions
thereof, and the Original Indenture (as supplemented and amended by the First
Supplemental Indenture and by this Third Supplemental Indenture) is in all
respects hereby ratified and confirmed. This Third Supplemental Indenture and
all its provisions shall be deemed a part of the Original Indenture in the
manner and to the extent herein and therein provided.

     

    SECTION
4.03.   Governing
Law. 

     

    This Third
Supplemental Indenture and the Notes shall be governed by and construed in
accordance with the laws of the State of New York without regard to principles
of conflicts of law.

     

    SECTION
4.04.   Counterparts. 

     

    This instrument may
be executed in any number of counterparts, each of which shall be deemed to be
an original, but all such counterparts shall together constitute but one and the
same instrument.

     

    (Signature
Pages Follow)

     

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     


    IN WITNESS WHEREOF,
the parties hereto have caused this Third Supplemental Indenture to be duly
executed and delivered, all as of the day and year first above
written.

     

    COLORADO INTERSTATE
GAS COMPANY

     

     

    By:/s/
Daniel B. Martin       

    Name: Daniel B.
Martin

    Title: Senior Vice
President

     

     

    ATTEST:

     

    By:/s/
Stacy J. James           

    Name: Stacy J.
James

    Title: Corporate
Secretary

     

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    



    THE BANK OF NEW
YORK TRUST COMPANY, N.A.

    as
Trustee

     

     

    By: /s/John
Stohlmann       

    Authorized
Signatory

     

     

    ATTEST:

     

    By: /s/
Patrick T. Giordano       

    Name: Patrick
T. Giordano    

    Title:
Vice President       

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    EXHIBIT
A

     

    [FORM
OF FACE OF NOTE]

     

    [If
a Global Security, insert—UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (“DTC”) (55 WATER STREET, NEW
YORK, NEW YORK) TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER,
EXCHANGE OR PAYMENT AND ANY NOTE ISSUED IS REGISTERED IN THE NAME OF CEDE &
CO., OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC,
AND ANY PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC, ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL, INASMUCH AS
THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST
HEREIN.]

     

    [If
a Global Security, insert—UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART
FOR THE INDIVIDUAL NOTES REGISTERED HEREBY, THIS GLOBAL NOTE MAY NOT BE
TRANSFERRED EXCEPT AS A WHOLE BY DTC TO A NOMINEE OF DTC OR BY A NOMINEE OF DTC
TO DTC OR ANOTHER NOMINEE OF DTC OR BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR OF
DTC OR A NOMINEE OF SUCH SUCCESSOR.]

     

    [If
a Transfer Restricted Security, insert—THIS NOTE HAS NOT BEEN REGISTERED UNDER
THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”) AND,
ACCORDINGLY, MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED WITHIN
THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S. PERSONS, EXCEPT
AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF OR OF A
BENEFICIAL INTEREST HEREIN, THE HOLDER (1) REPRESENTS THAT (A) IT IS A
“QUALIFIED INSTITUTIONAL BUYER” (AS DEFINED IN RULE 144A UNDER THE SECURITIES
ACT) (A “QIB”), (B) IT IS NOT A U.S. PERSON, IS NOT ACQUIRING THIS NOTE FOR THE
ACCOUNT OR BENEFIT OF A U.S. PERSON AND IS ACQUIRING THIS NOTE IN AN OFFSHORE
TRANSACTION IN COMPLIANCE WITH REGULATION S UNDER THE SECURITIES ACT OR (C) IT
IS AN INSTITUTIONAL “ACCREDITED INVESTOR” (AS DEFINED IN RULE 501(A)(1), (2),
(3) OR (7) OF REGULATION D UNDER THE SECURITIES ACT) (AN “IAI”), (2) AGREES THAT
IT WILL NOT, WITHIN THE TIME PERIOD REFERRED TO UNDER RULE 144(k) (TAKING INTO
ACCOUNT THE PROVISIONS OF RULE 144(d) UNDER THE SECURITIES ACT, IF APPLICABLE)
UNDER THE SECURITIES ACT AS IN EFFECT ON THE DATE OF THE TRANSFER OF THIS NOTE,
RESELL OR OTHERWISE TRANSFER THIS NOTE EXCEPT (A) TO THE ISSUER OR ANY
SUBSIDIARY THEREOF, (B) TO A PERSON WHOM THE HOLDER REASONABLY BELIEVES IS A QIB
PURCHASING FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QIB IN COMPLIANCE WITH
RULE 144A UNDER THE SECURITIES ACT, (C) OUTSIDE THE UNITED STATES IN AN OFFSHORE
TRANSACTION IN COMPLIANCE WITH RULE 904 UNDER THE SECURITIES ACT, (D) PURSUANT
TO THE EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT
(IF AVAILABLE), (E) TO AN IAI THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE
TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE REGISTRATION OF TRANSFER OF THIS NOTE (THE FORM OF WHICH LETTER
CAN BE OBTAINED FROM THE TRUSTEE) AND, IF SUCH TRANSFER IS IN RESPECT OF AN
AGGREGATE PRINCIPAL AMOUNT OF NOTES AT THE TIME OF TRANSFER OF LESS THAN
$250,000, AN OPINION OF COUNSEL ACCEPTABLE TO THE ISSUER THAT SUCH TRANSFER IS
IN COMPLIANCE WITH THE SECURITIES ACT OR (F) PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND, IN EACH CASE, IN ACCORDANCE
WITH APPLICABLE STATE SECURITIES LAWS, AND (3) AGREES THAT IT WILL DELIVER TO
EACH PERSON TO WHOM THIS NOTE OR AN INTEREST HEREIN IS TRANSFERRED A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF
THIS NOTE OR ANY INTEREST HEREIN WITHIN THE TIME PERIOD REFERRED TO ABOVE, THE
HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING
TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE TRUSTEE. AS
USED HEREIN, THE TERMS “OFFSHORE TRANSACTION,”“UNITED STATES” AND “U.S. PERSON”
HAVE THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S UNDER THE SECURITIES
ACT. THE INDENTURE CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO
REGISTER ANY TRANSFER OF THIS NOTE IN VIOLATION OF THE FOREGOING
RESTRICTIONS.]

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    COLORADO
INTERSTATE GAS COMPANY

     

    6.80%
Senior Note due 2015

     

    
      	
              Rate
      of Interest

               

            	
              Maturity
      Date

               

            	
              Original
      Issue Date

               

            
	
              6.80%

               

            	
              November 15,
      2015

               

            	
              ________ __,
      20__

               

            


    

     

     

    
      	
              No.
      _________

               

            	
              U.S.$_____________

               

            
	
              CUSIP No.
      ___________

               

            	 


    

    Colorado Interstate
Gas Company, a corporation duly organized and existing under the laws of the
State of Delaware (herein called the “Company”), for value
received, hereby promises to pay to ___________________________________ or
registered assigns, the principal sum of __________________________ on the
maturity date shown above, and to pay interest thereon, at the annual rate of
interest shown above, from the Original Issue Date shown above or from the most
recent Interest Payment Date (as hereinafter defined) to which interest has been
paid or duly provided for, payable semi-annually on May 15 and November 15 of
each year (each, an “Interest
Payment Date”) and at such
maturity date, commencing on the first such date after the Original Issue Date,
except that if the Original Issue Date is on or after a Regular Record Date (as
defined below) but before the next Interest Payment Date, interest payments will
commence on the second Interest Payment Date following the Original Issue
Date.

     

    The interest so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture, be paid to the person in whose name this
Note is registered at the close of business on the “Regular
Record Date” for any such
Interest Payment Date, which shall be the fifteenth calendar day (whether or not
a Business Day) preceding the applicable Interest Payment Date. Any such
interest not so punctually paid or duly provided for, and any interest payable
on such defaulted interest (to the extent lawful), will forthwith cease to be
payable to the Holder on such Regular Record Date and shall be paid to the
person in whose name this Note is registered at the close of business on a
special record date for the payment of such defaulted interest to be fixed by
the Company, notice of which shall be given to Holders of Notes not less than 15
days prior to such special record date. Payment of the principal of and interest
on this Note will be made at the agency of the Company maintained for that
purpose in New York, New York and at any other office or agency maintained by
the Company for such purpose, in United States dollars; provided, however, that at the
option of the Company payment of interest, other than interest due on the
maturity date shown above, may be made by check mailed to the address of the
person entitled thereto as such address shall appear in the Security
Register.

     

    Reference is hereby
made to the further provisions of this Note set forth on the reverse hereof,
which further provisions shall for all purposes have the same effect as if set
forth at this place.

     

    Unless the
certificate of authentication hereon has been executed by the Trustee referred
to on the reverse hereof by manual signature, this Note shall not be entitled to
any benefit under the Indenture or be valid or obligatory for any
purpose.

     

    (Signature
Page Follows)

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


        IN WITNESS WHEREOF,
COLORADO INTERSTATE GAS COMPANY has caused this
instrument to be executed in its corporate name by the signature of its duly
authorized officers.

     

    COLORADO INTERSTATE
GAS COMPANY

     

     

     

    By: /s/
Daniel B. Martin                

                       Name:  Daniel
B. Martin 

                       Title:    
Senior Vice President      

     

    ATTEST:

     

     

    By: /s/
Stacy J. James      

    Name:  Stacy
J. James

    Title:    
Corporate Secretary

     

     

     

     

    DATED:      

     

     

     

    TRUSTEE’S
CERTIFICATE OF AUTHENTICATION

     

    This is one of the
6.80% Senior Notes due 2015 referred to in the within-mentioned
Indenture.

     

    THE BANK OF NEW
YORK TRUST COMPANY, N.A.

     

    as
Trustee

     

     

     

    By:       

     

    Authorized
Signatory

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    [REVERSE
OF NOTE]

     

    
       

    


     

    COLORADO
INTERSTATE GAS COMPANY

     

    6.80%
Senior Note due 2015

     

    This Note is one of
a duly authorized issue of securities of the Company (which term includes any
successor corporation under the Indenture hereinafter referred to) designated as
its 6.80% Senior Notes due 2015 (the “Notes”), issued or to be
issued pursuant to an Indenture, dated as of June 27, 1997, between the Company
and The Bank of New York Trust Company, N.A. (successor-in-interest to Harris
Trust and Savings Bank), as Trustee (the “Trustee,” which term
includes any successor trustee under such Indenture), as amended and
supplemented by the First Supplemental Indenture thereto dated as of June 27,
1997 and the Second Supplemental Indenture thereto dated as of March 9, 2005 and
as further amended and supplemented by the Third Supplemental Indenture thereto
dated as of November 1, 2005 (such Indenture, as so amended and supplemented
being referred to herein as the “Indenture”). The terms of
this Note include those stated in the Indenture and those made part of the
Indenture by reference to the Trust Indenture Act of 1939, as amended. Reference
is hereby made to the Indenture and all further supplemental indentures thereto
for a statement of the respective rights, limitation of rights, duties and
immunities thereunder of the Company, the Trustee and the Holders and of the
terms upon which the Notes are, and are to be, authenticated and delivered.


     

    This Note is a
Series of Securities issued or to be issued by the Company under the Indenture.
The Indenture provides that the Securities of the Company referred to therein
(“Securities”), including the
Notes, may be issued in one or more Series, which different Series may be issued
in such aggregate principal amounts and on such terms (including, but not
limited to, terms relating to interest rate or rates, provisions for determining
such interest rate or rates and adjustments thereto, maturity, redemption
(optional and mandatory), sinking fund, covenants and Events of Default) as may
be provided in or pursuant to the Authorizing Resolutions and/or supplemental
indenture (if any) relating to the several Series.

     

    This Note is
redeemable, in whole or in part, at the Company’s option at any time prior to
its Stated Maturity at a redemption price equal to the greater of (a) 100% of
the principal amount of this Note, and (b) as determined by the Quotation Agent
(as defined below), the sum of the present values of the remaining scheduled
payments of principal and interest (not including any portion of those payments
of interest accrued as of the date of redemption) discounted to the date of
redemption on a semi-annual basis (assuming 360-day years, each consisting of
twelve 30-day months), at the Adjusted Treasury Rate (as defined below) plus 45
basis points plus, in each case, accrued interest to the date of
redemption.

     

    For purposes of
determining any redemption price, the following definitions shall
apply:

     

    “Adjusted
Treasury Rate” means, with
respect to any date of redemption, the rate per annum equal to the semi-annual
equivalent yield to maturity of the Comparable Treasury Issue, assuming a price
for the Comparable Treasury Issue (expressed as a percentage of its principal
amount) equal to the Comparable Treasury Price for the date of
redemption.

     

    “Comparable
Treasury Issue” means the United
States Treasury security selected by the Quotation Agent as having a maturity
comparable to the remaining term of this Note that would be utilized, at the
time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt securities of comparable maturity to the
remaining term of this Note.

     

    “Comparable
Treasury Price” means, with
respect to any date of redemption, (a) the average of the Reference Treasury
Dealer Quotations for the date of redemption, after excluding the highest and
lowest Reference Treasury Dealer Quotations, or (b) if the Trustee obtains fewer
than three Reference Treasury Dealer Quotations, the average of all such
Reference Treasury Dealer Quotations.

     

    “Quotation
Agent” means Citigroup
Global Markets Inc. or another Reference Treasury Dealer appointed by the
Company.

     

    “Reference
Treasury Dealer” means (a)
Citigroup Global Markets Inc. and its respective successors; provided, however, that if the
foregoing shall cease to be a primary U.S. Government securities dealer in New
York City (a “Primary
Treasury Dealer”), the Company
shall substitute another Primary Treasury Dealer; and (b) any other Primary
Treasury Dealers selected by the Company.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    “Reference
Treasury Dealer Quotations” means, with
respect to each Reference Treasury Dealer and any date of redemption, the
average, as determined by the Trustee, of the bid and asked prices for the
Comparable Treasury Issue (expressed in each case as a percentage of its
principal amount) quoted in writing to the Trustee by that Reference Treasury
Dealer at 5:00 p.m., New York City time, on the third business day preceding
that date of redemption.

     

    Unless the Company
defaults in payment of the redemption price, on and after the date of
redemption, interest will cease to accrue on this Note or the portions hereof
called for redemption.

     

    In the event of
redemption of this Note in part only, a new Note or Notes for the unredeemed
portion hereof shall be issued in the name of the Holder hereof upon the
surrender hereof.

     

    If an Event of
Default, as defined in the Indenture and in the Authorizing Resolution and/or
supplemental indenture (if any) relating to the Notes (if there shall be any
additional Events of Default specified in respect of the Notes), shall occur and
be continuing, the principal of all the Notes may be declared due and payable in
the manner and with the effect provided in the Indenture.

     

    The Indenture
permits, with certain exceptions as therein provided, the amendment thereof and
the modification of the rights and obligations of the Company and the rights of
the Holders of the Notes under the Indenture at any time by the Company and the
Trustee with the consent of the Holders of a majority in aggregate principal
amount of the Securities affected thereby, voting as a single class (which may
include the Notes), at the time outstanding. The Indenture also contains
provisions permitting the Holders of specified percentages in aggregate
principal amount of the Securities at the time outstanding to waive compliance
by the Company with certain provisions of the Indenture and certain past
defaults under the Indenture and their consequences. Any such consent or waiver
by the Holder of this Note shall be conclusive and binding upon such Holder and
upon all future Holders of this Note and of any Note issued upon the
registration of transfer hereof or in exchange herefor in lieu hereof, whether
or not notation of such consent or waiver is made upon this Note.

     

    The Indenture
provides that no Holder may pursue any remedy under the Indenture unless the
Trustee shall have failed to act after notice of an Event of Default and written
request by Holders of at least 25% in principal amount of the Securities of the
applicable Series and the offer to the Trustee of indemnity satisfactory to it;
however, such provision does not affect the right to sue for enforcement of any
overdue payment on any Security.

     

    No reference herein
to the Indenture and no provision of this Note or of the Indenture shall alter
or impair the obligation of the Company, which is absolute and unconditional, to
pay the principal of and interest on this Note at the times, places and rates,
and in the coin or currency, herein prescribed.

     

    As provided in the
Indenture and subject to certain limitations therein set forth, the transfer of
this Note is registrable in the Security Register upon surrender of this Note
for registration of transfer at the agency of the Company provided for that
purpose duly endorsed by, or accompanied by a written instrument of transfer in
substantially the form accompanying this Note duly executed by, the Holder
hereof or his attorney duly authorized in writing, and thereupon one or more new
Notes, of authorized denominations and for the same aggregate principal amount,
will be issued to the designated transferee or transferees.

     

    The Notes are
issuable only in registered form without coupons in denominations of $1,000 and
any integral multiple thereof. As provided in the Indenture and subject to
certain limitations therein set forth, the Notes are exchangeable for a like
aggregate principal amount of Notes of a different authorized denomination, as
requested by the Holder surrendering the same.

     

    No service charge
shall be made for any such registration of transfer or exchange, but the Company
may require payment of a sum sufficient to cover any transfer tax or similar
governmental charge payable in connection therewith (other than any such
transfer taxes or similar governmental charge payable upon exchanges pursuant to
Sections 2.11, 3A.08 or 9.05 of the Indenture, in which case such transfer taxes
or similar governmental charges shall be paid by the Company).

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    Prior to due
presentment of this Note for registration of transfer, the Company, the Trustee
and any agent of the Company or the Trustee may treat the person in whose name
this Note is registered as the owner hereof for all purposes, whether or not
this Note be overdue, and neither the Company, the Trustee nor any such agent
shall be affected by notice to the contrary.

     

    All terms used in
this Note which are defined in the Indenture shall have the meanings assigned to
them in the Indenture.

     

    Customary
abbreviations may be used in the name of a Note holder or any assignee, such as:
TEN COM ( = tenants in common), TEN ENT ( = tenants by the entireties), JT TEN (
= joint tenants with right of survivorship and not as tenants in common), CUST (
= Custodian) and U/G/M/A ( = Uniform Gifts to Minors Act).

     

    The Company will
furnish to any Note holder of record, upon written request, without charge, a
copy of the Indenture. Requests may be made to: Colorado Interstate Gas Company,
El Paso Building, 1001 Louisiana Street, Houston, Texas 77002, Attention:
Corporate Secretary.

     

    [If a Transfer
Restricted Security, insert—The Holder of this Note is entitled to the benefits
of the Registration Rights Agreement dated as of November 1, 2005 (the
“Registration
Rights Agreement”) by and among the
Company and the Initial Purchasers named therein, and such Holders shall also
have certain obligations to indemnify the Company under certain circumstances,
all as more fully set forth in the Registration Rights Agreement. In certain
events, the Company shall be required to pay to the Holder of this Note
liquidated damages on this Note, on the terms and subject to the conditions of
the Registration Rights Agreement.]

     

    This Note shall be
governed by and construed in accordance with the laws of the State of New York
without regard to principles of conflicts of law.

     

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    
       

    


    ASSIGNMENT
FORM

     

    FOR VALUE RECEIVED,
the undersigned hereby sell(s), assign(s) and transfer(s) unto
_____________________________________ (Please Print or Typewrite Name and
Address of Assignee) the within instrument of COLORADO INTERSTATE GAS COMPANY
and does hereby irrevocably constitute and appoint ________________________
Attorney to transfer said instrument on the books of the within-named Company,
with full power of substitution in the premises.

     

    Please Insert
Social Security or 

     

    Other Identifying
Number of Assignee: 

     

     

    Dated:      
               
 

                                               (Signature)


     

     

     

    Signature
Guarantee:
____________________________________________________________________________

    (Participant in a Recognized
Signature

    Guaranty Medallion
Program)

     

    NOTICE: The
signature to this assignment must correspond with the name as written upon the
face of the within instrument in every particular, without alteration or
enlargement or any change whatever.

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    EXCHANGE/TRANSFER
CERTIFICATE

     

    Re: 6.80% Senior Notes
due 2015 of Colorado Interstate Gas Company (the “Notes”).

     

    This
Exchange/Transfer Certificate relates to $____ principal amount of Notes held by
_____________________ (the “Transferor”).

     

    The Transferor has
requested the Trustee by written order to exchange or register the transfer of a
Note or Notes.

     

    In connection with
such request and in respect of each such Note, the Transferor does hereby
certify that the Transferor is familiar with the Indenture relating to the
above-captioned Notes and that the transfer of this Note does not require
registration under the Securities Act (as defined below) because:**

     

    ‪ Such Note is being
acquired for the Transferor’s own account without transfer.

     

    ‪ Such Note is being
transferred (i) to a “qualified institutional buyer” (as defined in Rule 144A
under the Securities Act of 1933, as amended (the “Securities
Act”)), in accordance
with Rule 144A under the Securities Act or (ii) pursuant to an exemption from
registration in accordance with Rule 904 of Regulation S under the Securities
Act (and in the case of clause (ii), based upon an opinion of counsel if the
Company or the Trustee so requests, together with a certification in
substantially the form of the Regulation S Certificate included in such
Note).

     

    ‪ Such Note is being
transferred (i) pursuant to an exemption from registration in accordance with
Rule 144 under the Securities Act (and based upon an opinion of counsel if the
Company or the Trustee so requests) or (ii) pursuant to an effective
registration statement under the Securities Act.

     

    ‪ Such Note is being
transferred in reliance on and in compliance with another exemption from the
registration requirements of the Securities Act (and based upon an opinion of
counsel if the Company or the Trustee so requests).

     

    [INSERT NAME OF
TRANSFEROR]

     

    By: 

    Name:

    Title:

    Address:

     

    Date:  

     

    **Check appropriate
box.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    REGULATION
S CERTIFICATE

     

    _________________,
_____

     

    The Bank of New
York Trust Company, N.A., as Registrar

    600 North Pearl
Street, Suite 420

    Dallas, TX
75201

     

    Attention:
Corporate Trust Administration

     

    Ladies and
Gentlemen:

     

    In connection with
our proposed sale of $_______________ principal amount of 6.80% Senior Notes due
2015 (the “Notes”) of Colorado
Interstate Gas Company (the “Company”), we confirm that
such sale has been effected pursuant to and in accordance with Regulation S
under the United States Securities Act of 1933, as amended (the “Securities
Act”), and,
accordingly, we represent that:

     

    (i) the offer of the
Notes was not made to a person in the United States of
America;

     

    
      	 	
              (ii)

            	
              at the time
      the buy order was originated, the transferee was outside the United States
      of America or we and any person acting on our behalf reasonably believed
      that the transferee was outside the United States of
    America;

            


    

     

    
      	 	
              (iii)

            	
              no directed
      selling efforts have been made by us in contravention of Rule 903 or Rule
      904 of Regulation S under the Securities Act, as
    applicable;

            


    

     

    
      	 	
              (iv)

            	
              the
      transaction is not part of a plan or scheme to evade the registration
      requirements of the Securities Act;
and

            


    

     

    
      	 	
              (v)

            	
              if the
      proposed transfer is being made prior to the expiration of the 40-day
      distribution compliance period as set forth in Regulation S, the transfer
      is not being made to, or for the benefit or account of, a U.S. Person
      (other than a distributor).

            


    

     

    You and the Company
are entitled to rely upon this Regulation S Certificate and you are irrevocably
authorized to produce this Regulation S Certificate or a copy hereof to any
interested party in any administrative or legal proceedings or official inquiry
with respect to the matters covered hereby. Terms used but not defined in this
Regulation S Certificate have the meanings set forth in Regulation S under the
Securities Act.

     

    Very truly
yours,

     

     

    [Name]

     

    By: 

    Name:

    Title:

    Address:

     

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    
 

    [If a Global
Security, insert as a separate page—

     

    SCHEDULE
OF INCREASES OR DECREASES

     

    IN
GLOBAL SECURITY

     

    The following
increases or decreases in this Global Security have been made:

     

    
      	
               

               

               

               

               

               

               

               

              Date
      of Exchange

               

            	
              Amount
      of Decrease in Principal Amount of this Global
      Security

               

            	
              Amount
      of Increase in Principal Amount of this 

               

              Global
      Security

               

            	
              Principal
      Amount of this Global Security following such decrease


               

              (or
      increase)

               

            	
               

               

              Signature
      of authorized signatory of Trustee or Depository]