1 EXHIBIT 5.3 ==================================== THIRD SUPPLEMENTAL INDENTURE Dated as of March 19, 1997 between MCN CORPORATION, AS ISSUER and NBD BANK AS TRUSTEE ===================================== 2 TABLE OF CONTENTS Page ---- ARTICLE I DEFINITIONS SECTION 1.1. Definition of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ARTICLE II GENERAL TERMS AND CONDITIONS OF THE DEBENTURES SECTION 2.1. Designation and Principal Amount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 SECTION 2.2. Maturity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 SECTION 2.3. Form and Payment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 SECTION 2.4. Global Debenture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 SECTION 2.5. Interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 SECTION 2.6. Sinking Fund . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 ARTICLE III EXTENSION OF INTEREST PAYMENT PERIOD SECTION 3.1. Extension of Interest Payment Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 SECTION 3.2. Notice of Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 SECTION 3.3. Limitation of Transactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 SECTION 3.4. Optional Repayment of Debentures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 SECTION 3.5. Repayment Procedure for Debentures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ARTICLE IV EXPENSES SECTION 4.1. Payment of Expenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 SECTION 4.2. Payment Upon Resignation or Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 ARTICLE V NOTICE SECTION 5.1. Notice by the Company . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 ARTICLE VI FORM OF DEBENTURE SECTION 6.1. Form of Debenture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 ARTICLE VII ORIGINAL ISSUE OF DEBENTURES SECTION 7.1. Original Issue of Debentures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 i 3 Page ---- ARTICLE VIII MISCELLANEOUS SECTION 8.1. Ratification of Indenture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 SECTION 8.2. Trustee Not Responsible for Recitals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 SECTION 8.3. Governing Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 SECTION 8.4. Separability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 SECTION 8.5. Counterparts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 ii 4 THIRD SUPPLEMENTAL INDENTURE, dated as of March 19, 1997 (the "Third Supplemental Indenture"), between MCN Corporation, a corporation duly organized and existing under the laws of the State of Michigan, having its principal office at 500 Griswold Street, Detroit, Michigan 48226 and doing business as MCN Energy Group Inc., (the "Company"), and NBD Bank, a Michigan banking corporation, as trustee (the "Trustee"). WHEREAS, the Company executed and delivered the indenture dated as of September 1, 1994 (the "Base Indenture") as supplemented by a first supplemental indenture, dated April 17, 1996 (the "First Supplemental Indenture") and the second supplemental indenture (the "Second Supplemental Indenture"), dated July 24, 1996, (the Base Indenture as so supplemented the "Indenture"), to the Trustee to provide for the future issuance of the Company's unsecured debentures, notes or other evidence of indebtedness (the "Securities"), to be issued from time to time in one or more series as might be determined by the Company under the Indenture; WHEREAS, pursuant to the terms of the Indenture, the Company desires to provide for the establishment of a new series of its Securities to be known as its 7-1/4% Junior Subordinated Debentures due 2002 (the "Debentures"), the form and substance of such Debentures and the terms, provisions and conditions thereof to be set forth as provided in the Indenture and this Third Supplemental Indenture; WHEREAS, MCN Financing III, a Delaware statutory business trust (the "Trust"), has offered to the public $132,250,000 million aggregate liquidation amount of its 7-1/4% Trust Originated Preferred Securities (the "Preferred Securities"), representing preferred undivided beneficial interests in the assets of the Trust and proposes to invest the proceeds from such offering, together with the proceeds of the issuance and sale by the Trust to the Company of $4,090,250 million aggregate liquidation amount of its 7-1/4% Trust Originated Common Securities, representing common undivided beneficial interests in the assets of the Trust (the "Common Securities" and together with the Preferred Securities, the "Trust Securities"), in $136,340,250 million aggregate principal amount of the Debentures; and WHEREAS, the Company has requested that the Trustee execute and deliver this Third Supplemental Indenture, 5 and all requirements necessary to make this Third Supplemental Indenture a valid instrument in accordance with its terms, and to make the Debentures, when executed by the Company and authenticated and delivered by the Trustee, the valid obligations of the Company, have been performed, and the execution and delivery of this Third Supplemental Indenture has been duly authorized in all respects: NOW THEREFORE, in consideration of the purchase and acceptance of the Debentures by the Holders thereof, and for the purpose of setting forth, as provided in the Indenture, the form and substance of the Debentures and the terms, provisions and conditions thereof, the Company covenants and agrees with the Trustee as follows: ARTICLE I DEFINITIONS SECTION 1.1. Definition of Terms. Unless the context otherwise requires: (a) a term defined in the Indenture has the same meaning when used in this Third Supplemental Indenture; (b) a term defined anywhere in this Third Supplemental Indenture has the same meaning throughout; (c) the singular includes the plural and vice versa; (d) headings are for convenience of reference only and do not affect interpretation; (e) the following terms have the meanings given to them in the Declaration: (i) Business Day; (ii) Clearing Agency; (iii) Delaware Trustee; (iv) Depositary; (v) Dissolution Tax Opinion; (vi) Preferred Security Certificate; (vii) Preferred Security Guaranty; (viii) Pricing Agreement; (ix) Institutional Trustee; (x) Regular Trustees; (xi) Special Event; (xii) Tax Event; (xiii) Investment Company Event; and (xiv) Underwriting Agreement; (f) the following terms have the meanings given to them in this Section 1.1(f): 2 6 "Additional Interest" shall have the meaning set forth in Section 2.5. "Compounded Interest" shall have the meaning set forth in Section 3.1. "Coupon Rate" shall have the meaning set forth in Section 2.5. "Debentures Repayment Price" shall have the meaning set forth in Section 3.5. "Declaration" means the Amended and Restated Declaration of Trust of MCN Financing III, a Delaware statutory business trust, dated as of March 19, 1997. "Deferred Interest" shall have the meaning set forth in Section 3.1. "Dissolution Event" means that, as a result of the occurrence and continuation of a Special Event, the Trust is to be dissolved in accordance with the Declaration, and the Debentures held by the Institutional Trustee are to be distributed to the holders of the Trust Securities issued by the Trust pro rata in accordance with the Declaration. "Extended Interest Payment Period" shall have the meaning set forth in Section 3.1. "Global Debenture" shall have the meaning set forth in Section 2.4. "Maturity Date" means the date on which the Debentures mature and on which the principal shall be due and payable together with all accrued and unpaid interest thereon including Compounded Interest and Additional Interest, if any. "Non Book-Entry Preferred Securities" shall have the meaning set forth in Section 2.4. "Put Option Exercise Date" shall have the meaning set forth in Section 3.4. "Purchase Contract Agreement" means the Purchase Contract Agreement, dated as of March 25, 1997 among the 3 7 Company and The First National Bank of Chicago, as purchase contract agent (the "Purchase Contract Agent"). (g) the following terms have the meaning given to them in the Purchase Contract Agreement: (i) Cash Settlement; (ii) Collateral Agent; (iii) Collateral Settlement; (iv) Early Settlement Date; (v) Pledge Agreement; (vi) Purchase Contract; and (vii) Purchase Contract Settlement Date. ARTICLE II GENERAL TERMS AND CONDITIONS OF THE DEBENTURES SECTION 2.1. Designation and Principal Amount. There is hereby authorized a series of Securities designated the "7-1/4% Junior Subordinated Debentures due 2002", limited in aggregate principal amount to $136,340,250 million, which amount shall be as set forth in any written order of the Company for the authentication and delivery of Debentures pursuant to Section 303 of the Indenture. SECTION 2.2. Maturity. The Maturity Date will be May 16, 2002. SECTION 2.3. Form and Payment. Except as provided in Section 2.4, the Debentures shall be issued in fully registered certificated form without interest coupons. Principal and interest on the Debentures will be payable, the transfer of such Debentures will be registrable and such Debentures will be exchangeable for Debentures bearing identical terms and provisions at the office or agency of the Institutional Trustee; provided, however, that payment of interest may be made at the option of the Company by check mailed to the Holder at such address as shall appear in the Security Register. Notwithstanding the foregoing, so long as the Holder of any Debentures is the Institutional Trustee or the Collateral Agent, the payment of the principal of and interest (including Compounded Interest and Additional Interest, if any) on such Debentures held by the Institutional Trustee or the Collateral Agent will be made at such place and to such account as may be designated in writing by the Institutional Trustee or the Collateral Agent, as the case may be, prior to such payment. 4 8 SECTION 2.4. Global Debenture. (a) In connection with a Dissolution Event, (i) the Debentures in certificated form may be presented to the Trustee by the Institutional Trustee in exchange for a global Debenture in an aggregate principal amount equal to the aggregate principal amount of all outstanding Debentures (a "Global Debenture"), to be registered in the name of the Depositary, or its nominee, and delivered by the Institutional Trustee to the Depositary for crediting to the accounts of its participants pursuant to the instructions of the Regular Trustees. The Company upon any such presentation shall execute a Global Debenture in such aggregate principal amount and deliver the same to the Trustee for authentication and delivery in accordance with the Indenture and this Third Supplemental Indenture. Payments on the Debentures issued as a Global Debenture will be made to the Depositary; and (ii) if any Preferred Securities are held in non book-entry certificated form, the Debentures in certificated form may be presented to the Trustee by the Institutional Trustee and any Preferred Security Certificate which represents Preferred Securities other than Preferred Securities held by the Clearing Agency or its nominee ("Non Book-Entry Preferred Securities") will be deemed to represent beneficial interests in Debentures presented to the Trustee by the Institutional Trustee having an aggregate principal amount equal to the aggregate liquidation amount of the Non Book-Entry Preferred Securities until such Preferred Security Certificates are presented to the Security Registrar for transfer or reissuance at which time such Preferred Security Certificates will be cancelled and a Debenture, registered in the name of the holder of the Preferred Security Certificate or the transferee of the holder of such Preferred Security Certificate, as the case may be, with an aggregate principal amount equal to the aggregate liquidation amount of the Preferred Security Certificate cancelled, will be executed by the Company and delivered to the Trustee for authentication and delivery in accordance with the Indenture and this Third Supplemental Indenture. On issue of such Debentures, Debentures with an equivalent aggregate principal amount that were presented by the Institutional 5 9 Trustee to the Trustee will be deemed to have been cancelled. (b) Unless and until it is exchanged for the Debentures in registered form, a Global Debenture may be transferred, in whole but not in part, only to another nominee of the Depositary, or to a successor Depositary selected or approved by the Company or to a nominee of such successor Depositary. (c) If at any time the Depositary notifies the Company that it is unwilling or unable to continue as Depositary or if at any time the Depositary for such series shall no longer be registered or in good standing under the Securities Exchange Act of 1934, as amended, or other applicable statute or regulation, and a successor Depositary for such series is not appointed by the Company within 90 days after the Company receives such notice or becomes aware of such condition, as the case may be, the Company will execute, and, subject to Article III of the Indenture, the Trustee, upon written notice from the Company, will authenticate and deliver the Debentures in definitive registered form without coupons, in authorized denominations, and in an aggregate principal amount equal to the principal amount of the Global Debenture in exchange for such Global Debenture. In addition, the Company may at any time determine that the Debentures shall no longer be represented by Global Debenture. In such event the Company will execute, and subject to Section 301 of the Indenture, the Trustee, upon receipt of an Officers Certificate evidencing such determination by the Company, will authenticate and deliver the Debentures in definitive registered form without coupons, in authorized denominations, and in an aggregate principal amount equal to the principal amount of the Global Debenture in exchange for such Global Debenture. Upon the exchange of the Global Debenture for such Debentures in definitive registered form without coupons, in authorized denominations, the Global Debenture shall be cancelled by the Trustee. Such Debentures in definitive registered form issued in exchange for the Global Debenture shall be registered in such names and in such authorized denominations as the Depositary, pursuant to instructions from its direct or indirect participants or otherwise, shall instruct the Trustee. The Trustee shall deliver such Securities to the Depositary for delivery to the Persons in whose names such Securities are so registered. 6 10 SECTION 2.5. Interest. (a) Each Debenture will bear interest at the rate of 7-1/4% per annum (the "Coupon Rate") from the original date of issuance until the principal thereof becomes due and payable, and on any overdue principal and (to the extent that payment of such interest is enforceable under applicable law) on any overdue installment of interest at the Coupon Rate, compounded quarterly, payable (subject to the provisions of Article IV) quarterly in arrears on March 31, June 30, September 30 and December 31 of each year (each, an "Interest Payment Date," commencing on June 30, 1997), to the Person in whose name such Debenture or any predecessor Debenture is registered, at the close of business on the regular record date for such interest installment, which, in respect of (i) Debentures of which the Institutional Trustee is the Holder and the Preferred Securities are in book-entry only form or (ii) a Global Debenture, shall be the close of business on the Business Day next preceding that Interest Payment Date. Notwithstanding the foregoing sentence, if (i) the Debentures are held by the Institutional Trustee and the Preferred Securities are no longer in book-entry only form or (ii) the Debentures are not represented by a Global Debenture, the Company may select a regular record date for such interest installment which shall be any date at least one Business Day before an Interest Payment Date. (b) The amount of interest payable for any period will be computed on the basis of a 360-day year of twelve 30-day months. Except as provided in the following sentence, the amount of interest payable for any period shorter than a full quarterly period for which interest is computed, will be computed on the basis of the actual number of days elapsed per 30-day month. In the event that any date on which interest is payable on the Debentures is not a Business Day, then payment of interest payable on such date will be made on the next succeeding day which is a Business Day (and without any interest or other payment in respect of any such delay), except that, if such Business Day is in the next succeeding calendar year, such payment shall be made on the immediately preceding Business Day, in each case with the same force and effect as if made on such date. (c) If, at any time while the Institutional Trustee or the Collateral Agent is the Holder of any Debentures, the Trust or the Institutional Trustee or the Collateral Agent is required to pay any taxes, duties, assessments 7 11 or governmental charges of whatever nature (other than withholding taxes) imposed by the United States, or any other taxing authority, then, in any case, the Company will pay as additional interest ("Additional Interest") on the Debentures held by the Institutional Trustee or the Collateral Agent, such additional amounts as shall be required so that the net amounts received and retained by the Trust and the Institutional Trustee or the Collateral Agent after paying such taxes, duties, assessments or other governmental charges will be equal to the amounts the Trust and the Institutional Trustee or the Collateral Agent would have received had no such taxes, duties, assessments or other government charges been imposed. SECTION 2.6. Sinking Fund. The Debentures are not entitled to the benefit of any sinking fund. ARTICLE III EXTENSION OF INTEREST PAYMENT PERIOD SECTION 3.1. Extension of Interest Payment Period. The Company shall have the right, at any time and from time to time during the term of the Debentures, to defer payments of interest by extending the interest payment period of such Debentures for a period not extending beyond the date of maturity of the Debentures (the "Extended Interest Payment Period"), during which Extended Interest Payment Period no interest shall be due and payable. To the extent permitted by applicable law, interest, the payment of which has been deferred because of the extension of the interest payment period pursuant to this Section 3.1, will bear interest thereon at the Coupon Rate compounded quarterly for each quarter of the Extended Interest Payment Period ("Compounded Interest"). At the end of the Extended Interest Payment Period, the Company shall pay all interest accrued and unpaid on the Debentures, including any Additional Interest and Compounded Interest (together, "Deferred Interest") that shall be payable to the Holders of the Debentures in whose names the Debentures are registered in the Security Register on the first record date after the end of the Extended Interest Payment Period. Before the termination of any Extended Interest Payment Period, the Company may further extend such period, provided that such period together 8 12 with all such previous and further extensions thereof shall not exceed 20 consecutive quarters or extend beyond the maturity date of the Debentures. Upon the termination of any Extended Interest Payment Period and upon the payment of all Deferred Interest then due, the Company may commence a new Extended Interest Payment Period, subject to the foregoing requirements. No interest shall be due and payable during an Extended Interest Payment Period, except at the end thereof, but the Company may prepay at any time all or any portion of the interest accrued during an Extended Interest Payment Period. SECTION 3.2. Notice of Extension. (a) If the Institutional Trustee or the Collateral Agent is the only registered Holder of the Debentures at the time the Company selects an Extended Interest Payment Period, the Company shall give written notice to the Regular Trustees, the Institutional Trustee, the Collateral Agent, and the Trustee of its selection of such Extended Interest Payment Period one Business Day before the earlier of (i) the next succeeding date on which Distributions on the Trust Securities issued by the Trust are payable, or (ii) the date the Trust is required to give notice of the record date, or the date such Distributions are payable, to the New York Stock Exchange or other applicable self-regulatory organization or to holders of the Preferred Securities issued by the Trust, but in any event at least one Business Day before such record date. (b) If the Institutional Trustee or the Collateral Agent is not the only Holder of the Debentures at the time the Company selects an Extended Interest Payment Period, the Company shall give the Holders of the Debentures and the Trustee written notice of its selection of such Extended Interest Payment Period at least 10 Business Days before the next succeeding Interest Payment Date. (c) The quarter in which any notice is given pursuant to paragraphs (a) or (b) of this Section 3.2 shall be counted as one of the 20 quarters permitted in the maximum Extended Interest Payment Period permitted under Section 3.1. 9 13 SECTION 3.3. Limitation of Transactions. If (i) the Company shall exercise its right to defer payment of interest as provided in Section 4.1, then (a) the Company shall not declare or pay any dividends on, make any distributions with respect to, or redeem, purchase, acquire or make a liquidation payment with respect to, any of its capital stock (other than (i) purchases or acquisitions of shares of its common stock in connection with the satisfaction by the Company of its obligations under any employee benefit plans or the satisfaction by the Company of its obligations pursuant to any contract or security outstanding on the date of such event requiring the Company to purchase shares of its common stock, (ii) as a result of a reclassification of its capital stock or the exchange or conversion of one class or series of its capital stock for another class or series of its capital stock or, (iii) the purchase of fractional interests in shares of its capital stock pursuant to the conversion or exchange provisions of such capital stock or security being converted or exchanged) or make any guarantee payment with respect thereto, (b) the Company shall not make any payment of interest, principal or premium, if any, on or repay, repurchase or redeem any debt securities issued by the Company which rank pari passu with or junior to the Debentures and (c) the Company shall not make any guarantee payments with respect to the foregoing (other than pursuant to the Preferred Security Guaranty). SECTION 3.4. Optional Repayment of Debentures. Each Holder of Debentures, including the Institutional Trustee and the Collateral Agent, shall have the right (the "Put Option") to require the Company to repay all or a portion (which portion must be $50 or any integral multiple thereof) of the Debentures held by such Holder, on May 16, 2000, the Purchase Contract Settlement Date (the "Put Option Exercise Date"), at a repayment price equal to 100% of the principal amount thereof plus any accrued and unpaid interest thereon, including Additional Interest, if any, to the date of such repayment (the "Debentures Repayment Price"). SECTION 3.5. Repayment Procedure for Debentures. (a) In order for the Debentures to be repaid on the Put Option Exercise Date, the Company must receive at the Corporate Trust Office of the Trustee in the City of 10 14 Detroit, Michigan, not less than 10 nor more than 30 days prior to the Put Option Exercise Date, the Debentures to be repaid with the form entitled "Option to Elect Repayment" on the reverse of or otherwise accompanying such Debentures duly completed. Any such notice received by the Company shall be irrevocable. All questions as to the validity, eligibility (including time of receipt) and acceptance of the Debentures for repayment shall be determined by the Company, whose determination shall be final and binding. Notwithstanding the foregoing, so long as the Holder is the Institutional Trustee or the Collateral Agent, and assuming prior notice to the Trustee, such Debentures may be received at the Corporate Trust Office (as defined in the Declaration) of the Institutional Trustee in the City of Wilmington, Delaware at any time prior to 11:00 a.m., New York City time, on the Put Option Exercise Date in the form and manner as may be designated by the Institutional Trustee or the Collateral Agent and acceptable to the Trustee. (b) Payment of the Debentures Repayment Price to Holders of Debentures shall be made through the Trustee, subject to the Trustee's receipt of payment from the Company in accordance with the terms of the Indenture. Notwithstanding the foregoing, so long as the Holder of any Debentures presented for repayment is the Institutional Trustee or the Collateral Agent, the payment of the Debentures Repayment Price in respect of such Debentures shall be made, either through the Trustee or the Company acting as Paying Agent, no later than 12:00 noon, New York City time, on the Put Option Exercise Date, by check or wire transfer, in immediately available funds, at such place and to such account as may be designated by the Institutional Trustee or the Collateral Agent, as the case may be. If the Trustee holds immediately available funds sufficient to pay the Debentures Repayment Price of the Debentures presented for repayment (or, if the Company is acting as Paying Agent or the Institutional Trustee has received the Debentures Repayment Price), then, immediately prior to the close of business on the Put Option Exercise Date, such Debentures will cease to be outstanding and interest thereon will cease to accrue, whether or not such Debentures have been received by the Company, and all other rights of the Holder in respect of the Debentures, including the Holder's right to require the Company to repay such Debentures, shall terminate and lapse (other than the right to receive the Debentures Repayment Price upon delivery of such Debentures but without interest on such Debentures Repayment Price). Neither the 11 15 Institutional Trustee nor the Company will be required to register or cause to be registered the transfer of any Debentures for which repayment has been elected. ARTICLE IV EXPENSES SECTION 4.1. Payment of Expenses. In connection with the offering, sale and issuance of the Debentures to the Institutional Trustee and in connection with the sale of the Trust Securities by the Trust, the Company, in its capacity as borrower with respect to the Debentures, shall: (a) pay all costs and expenses relating to the offering, sale and issuance of the Debentures, including commissions to the underwriters payable pursuant to the Underwriting Agreement and the Pricing Agreement and compensation of the Trustee under the Indenture in accordance with the provisions of Section 607 of the Indenture; (b) pay all costs and expenses of the Trust (including, but not limited to, costs and expenses relating to the organization of the Trust, the offering, sale and issuance of the Trust Securities (including commissions to the underwriters in connection therewith), the fees and expenses of the Institutional Trustee and the Delaware Trustee, the costs and expenses relating to the operation of the Trust, including without limitation, costs and expenses of accountants, attorneys, statistical or bookkeeping services, expenses for printing and engraving and computing or accounting equipment, paying agent(s), registrar(s), transfer agent(s), duplicating, travel and telephone and other telecommunications expenses and costs and expenses incurred in connection with the acquisition, financing, and disposition of Trust assets); (c) be primarily liable for any indemnification obligations arising with respect to the Declaration; and (d) pay any and all taxes (other than United States withholding taxes attributable to the Trust or its assets) and all liabilities, costs and expenses with respect to such taxes of the Trust. 12 16 SECTION 4.2. Payment Upon Resignation or Removal. Upon termination of this Third Supplemental Indenture or the Indenture or the removal or resignation of the Trustee pursuant to this Section 4.2, the Company shall pay to the Trustee all amounts accrued to the date of such termination, removal or resignation. Upon termination of the Declaration or the removal or resignation of the Delaware Trustee or the Institutional Trustee, as the case may be, pursuant to Section 5.6 of the Declaration, the Company shall pay to the Delaware Trustee or the Institutional Trustee, as the case may be, all amounts accrued to the date of such termination, removal or resignation. ARTICLE V NOTICE SECTION 5.1. Notice by the Company. The Company shall give prompt written notice to a Responsible Officer of the Trustee of any fact known to the Company that would prohibit the making of any payment of monies to or by the Trustee in respect of the Debentures pursuant to the provisions of this Article VI. Notwithstanding the provisions of Article Fourteen of the Indenture or any other provision of the Indenture and this Third Supplemental Indenture, the Trustee shall not be charged with knowledge of the existence of any facts that would prohibit the making of any payment of monies to or by the Trustee in respect of the Debentures pursuant to the provisions of Article Fourteen of the Indenture, unless and until a Responsible Officer of the Trustee shall have received written notice thereof from the Company or a holder or holders of Senior Indebtedness or from any trustee therefor; and before the receipt of any such written notice, the Trustee, subject to the provisions of Section 601 of the Indenture, shall be entitled in all respects to assume that no such facts exist; provided, however, that if the Trustee shall not have received the notice provided for in this Article 6 at least two Business Days prior to the date upon which by the terms hereof any money may become payable for any purpose (including, without limitation, the payment of the principal of (or premium, if any) or interest on any Debenture), then, anything herein contained to the contrary notwithstanding, the Trustee shall have full power and authority to receive such money and to apply the same to the purposes for which they 13 17 were received, and shall not be affected by any notice to the contrary that may be received by it within two Business Days prior to such date. The Trustee, subject to the provisions of Section 601 of the Indenture, shall be entitled to conclusively rely on the delivery to it of a written notice by a Person representing himself to be a holder of Senior Indebtedness of the Company, as the case may be (or a trustee on behalf of such holder), to establish that such notice has been given by a holder of such Senior Indebtedness or a trustee on behalf of any such holder or holders. In the event that the Trustee determines in good faith that further evidence is required with respect to the right of any Person as a holder of such Senior Indebtedness to participate in any payment or distribution pursuant to this Article VI, the Trustee may request such Person to furnish evidence to the reasonable satisfaction of the Trustee as to the amount of such Senior Indebtedness held by such Person, the extent to which such Person is entitled to participate in such payment or distribution and any other facts pertinent to the rights of such Person under this Article VI, and, if such evidence is not furnished, the Trustee may defer any payment to such Person pending judicial determination as to the right of such Person to receive such payment. ARTICLE VI FORM OF DEBENTURE SECTION 6.1. Form of Debenture. The Debentures and the Trustee's Certificate of Authentication to be endorsed thereon are to be substantially in the following forms: (FORM OF FACE OF DEBENTURE) [IF THE DEBENTURE IS TO BE A GLOBAL DEBENTURE, INSERT - This Debenture is a Global Debenture within the meaning of the Indenture hereinafter referred to and is registered in the name of a Depositary or a nominee of a Depositary. This Debenture is exchangeable for Debentures registered in the name of a person other than the Depositary or its nominee only in the limited circumstances described in the Indenture, and no transfer of this Debenture (other than a transfer of this Debenture as a whole by the Depositary to a nominee of the Deposi- 14 18 tary or by a nominee of the Depositary to the Depositary or another nominee of the Depositary) may be registered except in limited circumstances. Unless this Debenture is presented by an authorized representative of The Depository Trust Company (55 Water Street, New York, New York) to the issuer or its agent for registration of transfer, exchange or payment, and any Debenture issued is registered in the name of Cede & Co. or such other name as requested by an authorized representative of The Depository Trust Company and any payment hereon is made to Cede & Co., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY A PERSON IS WRONGFUL since the registered owner hereof, Cede & Co., has an interest herein.] No. __________________ $_____________________ CUSIP No. ____________ 15 19 MCN CORPORATION ___% JUNIOR SUBORDINATED DEBENTURE DUE 2002 MCN CORPORATION, a Michigan corporation (the "Company", doing business as MCN Energy Group Inc., which term includes any successor corporation under the Indenture hereinafter referred to), for value received, hereby promises to pay to ______________ or registered assigns, the principal sum of _____________ Dollars ($___________) on ________, 2002, and to pay interest on said principal sum from March __, 1997, or from the most recent interest payment date (each such date, an "Interest Payment Date") to which interest has been paid or duly provided for, quarterly (subject to deferral as set forth herein) in arrears on March 31, June 30, September 30 and December 31 of each year commencing June 30, 1997, at the rate of ___% per annum until the principal hereof shall have become due and payable, and on any overdue principal and premium, if any, and (without duplication and to the extent that payment of such interest is enforceable under applicable law) on any overdue installment of interest at the same rate per annum compounded quarterly. The amount of interest payable on any Interest Payment Date shall be computed on the basis of a 360-day year of twelve 30-day months. Except as provided in the following sentence, the amount of interest payable for any period shorter than a full quarterly period for which interest is computed, will be computed on the basis of the actual number of days elapsed per 30-day month. In the event that any date on which interest is payable on this Debenture is not a Business Day, then payment of interest payable on such date will be made on the next succeeding day that is a Business Day (and without any interest or other payment in respect of any such delay), except that, if such Business Day is in the next succeeding calendar year, such payment shall be made on the immediately preceding Business Day, in each case with the same force and effect as if made on such date. The interest installment 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 Debenture (or one or more Predecessor Securities, as defined in said Indenture) is registered at the close of business on the regular record date for such interest installment, which shall be the close of business on the business day next preceding such Interest Payment Date. [IF PURSUANT TO THE PROVISIONS OF THE INDENTURE THE DEBEN- 16 20 TURES ARE NO LONGER REPRESENTED BY A GLOBAL DEBENTURE -- which shall be the close of business on the ____ business day next preceding such Interest Payment Date.] Any such interest installment not punctually paid or duly provided for shall forthwith cease to be payable to the registered Holders on such regular record date and may be paid to the Person in whose name this Debenture (or one or more Predecessor Securities) is registered at the close of business on a special record date to be fixed by the Trustee for the payment of such defaulted interest, notice whereof shall be given to the registered Holders of this series of Debentures not less than 10 days prior to such special record date, or may be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Debentures may be listed, and upon such notice as may be required by such exchange, all as more fully provided in the Indenture. The principal of (and premium, if any) and the interest on this Debenture shall be payable at the office or agency of the Trustee maintained for that purpose in any coin or currency of the United States of America that at the time of payment is legal tender for payment of public and private debts; provided, however, that payment of interest may be made at the option of the Company by check mailed to the registered Holder at such address as shall appear in the Security Register. Notwithstanding the foregoing, so long as the Holder of this Debenture is the Institutional Trustee or, if applicable, the Collateral Agent, the payment of the principal of (and premium, if any) and interest on this Debenture will be made at such place and to such account as may be designated in writing by the Institutional Trustee or, if applicable, the Collateral Agent. The indebtedness evidenced by this Debenture is, to the extent provided in the Indenture, subordinate and junior in right of payment to the prior payment in full of all Senior Indebtedness and pari passu in right of payment with the Company's other junior subordinated debentures, and this Debenture is issued subject to the provisions of the Indenture with respect thereto. Each Holder of this Debenture, by accepting the same, (a) agrees to and shall be bound by such provisions, (b) authorizes and directs the Trustee on his or her behalf to take such action as may be necessary or appropriate to acknowledge or effectuate the subordination so provided and (c) appoints the Trustee his or her attorney-in-fact for any and all such purposes. Each Holder hereof, by his or her acceptance hereof, hereby 17 21 waives all notice of the acceptance of the subordination provisions contained herein and in the Indenture by each holder of Senior Indebtedness, whether now outstanding or hereafter incurred, and waives reliance by each such holder upon said provisions. This Debenture shall not be entitled to any benefit under the Indenture hereinafter referred to, be valid or become obligatory for any purpose until the Certificate of Authentication hereon shall have been signed by or on behalf of the Trustee. 18 22 The provisions of this Debenture are continued on the reverse side hereof and such continued provisions shall for all purposes have the same effect as though fully set forth at this place. IN WITNESS WHEREOF, the Company has caused this instrument to be executed. Dated ___________________ MCN CORPORATION By: ______________________________ Name: Title Attest: By: _____________________ Name: Title: CERTIFICATE OF AUTHENTICATION This is one of the Securities of the series of Securities described in the within-mentioned Indenture. Dated ___________________ NBD BANK as Trustee By ______________________________ Authorized Signatory 19 23 (FORM OF REVERSE OF DEBENTURE) This Debenture is one of a duly authorized series of Securities of the Company (herein sometimes referred to as the "Securities"), specified in the Indenture, all issued or to be issued in one or more series under and pursuant to an Indenture dated as of September 1, 1994, duly executed and delivered between the Company and NBD Bank, as Trustee (the "Trustee") (as supplemented by a First Supplemental Indenture, dated April 17, 1996, and a Second Supplemental Indenture, dated July 24, 1996, as so supplemented, the "Base Indenture"), as supplemented by a Third Supplemental Indenture dated as of March 19, 1997, between the Company and the Trustee (the Base Indenture as so supplemented, the "Indenture"), to which Indenture and all indentures supplemental thereto reference is hereby made for a description of the rights, limitations of rights, obligations, duties and immunities thereunder of the Trustee, the Company and the Holders of the Securities. By the terms of the Indenture, the Securities are issuable in series that may vary as to amount, date of maturity, rate of interest and in other respects as provided in the Indenture. This series of Securities is limited in aggregate principal amount as specified in said Third Supplemental Inden- ture. The Debentures are not entitled to the benefit of any sinking fund. The Holder of this Debenture, including the Institutional Trustee or, if applicable, the Collateral Agent, shall have the right (the "Put Option") to require the Company to repay all or a portion (which portion must be $50 or any integral multiple thereof) of this Debenture on May 16, 2000, the Purchase Contract Settlement Date (the "Put Option Exercise Date") at a repayment price equal to 100% of the principal amount thereof plus any accrued but unpaid interest, including Additional Interest, if any, to the date of such repayment (the "Debentures Repayment Price"). In order for the Debentures to be repaid on the Put Option Exercise Date, the Company must receive at the Corporate Trust Office of the Trustee in the City of Detroit, Michigan, not less than 10 nor more than 30 days prior to the Put Option Exercise Date, the Debentures to be repaid with the form entitled "Option to Elect repayment" hereon duly completed. Any such notice received by the Company shall be irrevocable. All questions as to the validity, eligibility (including time of receipt) and accep- 20 24 tance of the Debentures for repayment shall be determined by the Company, whose determination shall be final and binding. Notwithstanding the foregoing, so long as the Holder is the Institutional Trustee or the Collateral Agent, and assuming prior notice to the Trustee, this Debenture may be received at the Corporate Trust Office (as defined in the Declaration) of the Institutional Trustee at any time prior to 11:00 a.m., New York City time, on the Put Option Exercise Date in the form and manner as may be designated by the Institutional Trustee or the Collateral Agent and acceptable to the Trustee. In case an Event of Default, as defined in the Indenture, shall have occurred and be continuing, the principal of all of the Debentures may be declared, and upon such declaration shall become, due and payable, in the manner, with the effect and subject to the conditions provided in the Indenture. The Indenture contains provisions permitting the Company and the Trustee, with the consent of the Holders of not less than a majority in aggregate principal amount of the Debentures of each series affected at the time outstanding, as defined in the Indenture, to execute supplemental indentures for the purpose of adding any provisions to or changing in any manner or eliminating any of the provisions of the Indenture or of any supplemental indenture or of modifying in any manner the rights of the Holders of the Debentures; provided, however, that no such supplemental indenture shall (i) change the Stated Maturity of the principal of, or any installment of principal of or interest on, any Debentures of any series or reduce the principal amount thereof, or reduce the rate or extend the time of payment of interest thereon, or reduce any premium payable upon the redemption thereof, without the consent of the Holder of each Debenture so affected, or (ii) reduce the aforesaid percentage of Debentures, the Holders of which are required to consent to any such supplemental indenture, without the consent of the Holders of each Debenture then outstanding and affected thereby. The Indenture also contains provisions permitting the Holders of a majority in aggregate principal amount of the Securities of any series at the time outstanding affected thereby, on behalf of all of the Holders of the Debentures of such series, to waive any Default or Event of Default with respect to such series, and its consequences, except a Default or Event of Default in the payment of the principal of or premium, if any, or interest 21 25 on any of the Securities of such series. Any such consent or waiver by the registered Holder of this Debenture (unless revoked as provided in the Indenture) shall be conclusive and binding upon such Holder and upon all future Holders and owners of this Debenture and of any Debenture issued in exchange therefor or in place hereof (whether by registration of transfer or otherwise), irrespective of whether or not any notation of such consent or waiver is made upon this Debenture. No reference herein to the Indenture and no provision of this Debenture or of the Indenture shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay the principal of and premium, if any, and interest on this Debenture at the time and place and at the rate and in the money herein prescribed. So long as the Company is not in default in the payment of interest on the Debentures, the Company shall have the right at any time during the term of the Debentures and from time to time to extend the interest payment period of such Debentures for a period not exceeding beyond the maturity date of the Debentures (an "Extended Interest Payment Period"), at the end of which period the Company shall pay all interest then accrued and unpaid (together with the interest thereon at the rate specified for the Debentures to the extent that payment of such interest is enforceable under applicable law). In the event that the Company exercises this right, then (a) the Company shall not declare or pay dividends on, make distributions with respect to, or redeem, purchase or acquire, or make a liquidation payment with respect to, any of its capital stock (other than (i) purchases or acquisitions of shares of its Common Stock in connection with the satisfaction by the Company of its obligations under any employee benefit plans or the satisfaction by the Company of its obligations pursuant to any contract or security outstanding on the date of such event requiring the Company to purchase shares of the Company's Common Stock, (ii) as a result of a reclassification of the Company's capital stock or the exchange or conversion of one class or series of the Company's capital stock for another class or series of the Company's capital stock or (iii) the purchase of fractional interests in shares of the Company's capital stock pursuant to the conversion or exchange provisions of such capital stock or the security being converted or exchanged) or make any guarantee payments with respect to the foregoing), (b) the Company shall not make any payment 22 26 of interest, principal or premium, if any, on or repay, repurchase or redeem any debt securities (including guarantees) issued by the Company that rank pari passu with or junior to such Debentures and (c) the Company shall not make any guarantee payments with respect to the foregoing (other than pursuant to the Preferred Securities Guarantee). Prior to the termination of any such Extended Interest Payment Period, the Company may further extend the interest payment period; provided, however, that such Extended Interest Payment Period, together with all such previous and further extensions thereof, may not exceed beyond the maturity date of the Debentures. As provided in the Indenture and subject to certain limitations therein set forth, this Debenture is transferable by the registered Holder hereof on the Security Register of the Company, upon surrender of this Debenture for registration of transfer at the office or agency of the Trustee in the City of Detroit and State of Michigan accompanied by a written instrument or instruments of transfer in form satisfactory to the Company or the Trustee duly executed by the registered Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Debentures of authorized denominations and for the same aggregate principal amount and series will be issued to the designated transferee or transferees. No service charge will be made for any such transfer, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in relation thereto. Prior to due presentment for registration of transfer of this Debenture, the Company, the Trustee, any paying agent and the Security Registrar may deem and treat the registered holder hereof as the absolute owner hereof (whether or not this Debenture shall be overdue and notwithstanding any notice of ownership or writing hereon made by anyone other than the Security Registrar) for the purpose of receiving payment of or on account of the principal hereof and premium, if any, and interest due hereon and for all other purposes, and neither the Company nor the Trustee nor any paying agent nor any Security Registrar shall be affected by any notice to the contrary. No recourse shall be had for the payment of the principal of or the interest on this Debenture, or for any claim based hereon, or otherwise in respect hereof, or based on or in respect of the Indenture, against any incorporator, 23 27 stockholder, officer or director, past, present or future, as such, of the Company or of any predecessor or successor corporation, whether by virtue of any constitution, statute or rule of law, or by the enforcement of any assessment or penalty or otherwise, all such liability being, by the acceptance hereof and as part of the consideration for the issuance hereof, expressly waived and released. The Indenture imposes certain limitations on the ability of the Company to, among other things, merge or consolidate with any other Person or sell, assign, transfer or lease all or substantially all of its properties or assets. All such covenants and limitations are subject to a number of important qualifications and exceptions. The Company must report periodically to the Trustee on compliance with the covenants in the Indenture. The Debentures of this series are issuable only in registered form without coupons in denominations of $50 and any integral multiple thereof. This Global Debenture is exchangeable for Debentures in definitive form only under certain limited circumstances set forth in the Indenture. Debentures of this series so issued are issuable only in registered form without coupons in denominations of $50 and any integral multiple thereof. As provided in the Indenture and subject to certain limitations therein set forth, Debentures of this series so issued are exchangeable for a like aggregate principal amount of Debentures of this series of a different authorized denomination, as requested by the Holder surrendering the same. All terms used in this Debenture that are defined in the Indenture shall have the meanings assigned to them in the Indenture. ARTICLE VII ORIGINAL ISSUE OF DEBENTURES SECTION 7.1. Original Issue of Debentures. Debentures in the aggregate principal amount of $136,340,250 may, upon execution of this Third Supplemental Indenture, be executed by the Company and delivered to the Trustee for authentication, and the Trustee shall thereupon authenticate and deliver said Debentures to or upon the written order of the Company, signed by its Chairman, its 24 28 Vice Chairman, its President, or any Vice President and its Treasurer, Assistant Treasurer, Secretary or Assistant Secretary, without any further action by the Company. ARTICLE VIII MISCELLANEOUS SECTION 8.1. Ratification of Indenture. The Indenture, as supplemented by this Third Supplemental Indenture, is in all respects ratified and confirmed, and this Third Supplemental Indenture shall be deemed part of the Indenture in the manner and to the extent herein and therein provided. SECTION 8.2. Trustee Not Responsible for Recitals. The recitals herein contained are made by the Company and not by the Trustee, and the Trustee assumes no responsibility for the correctness thereof. The Trustee makes no representation as to the validity or sufficiency of this Third Supplemental Indenture. SECTION 8.3. Governing Law. This Third Supplemental Indenture and each Debenture shall be deemed to be a contract made under the internal laws of the State of New York, and for all purposes shall be construed in accordance with the laws of said State. SECTION 8.4. Separability. In case any one or more of the provisions contained in this Third Supplemental Indenture or in the Debentures shall for any reason be held to be invalid, illegal or unenforceable in any respect, such invalidity, illegality or unenforceability shall not affect any other provisions of this Third Supplemental Indenture or of the Debentures, but this Third Supplemental Indenture and the Debentures shall be construed as if such invalid or illegal or unenforceable provision had never been contained herein or therein. 25 29 SECTION 8.5. Counterparts. This Third Supplemental Indenture may be executed in any number of counterparts each of which shall be an original; but such counterparts shall together constitute but one and the same instrument. 26 30 IN WITNESS WHEREOF, the parties hereto have caused this Third Supplemental Indenture to be duly executed, and their respective corporate seals to be hereunto affixed and attested, on the date or dates indicated in the acknowledgements and as of the day and year first above written. MCN CORPORATION By /s/ Sebastian Coppola ---------------------------- Name: Sebastian Coppola Title: Senior Vice President and Treasurer Attest: By: /s/ Daniel L. Schiffer -------------------------- Daniel L. Schiffer Senior Vice President, General Counsel and Secretary NBD BANK as Trustee By /s/ James D. Khami --------------------------- Name: James D. Khami Title: Trust Officer Attest: By: /s/ Daniel T. Lis ------------------------ Daniel T. Lis