DESCRIPTION OF DEBT SECURITIES

General

The senior debt securities and the subordinated debt securities, which we refer to collectively as the “debt securities”, will be issued under one of two separate indentures, as each may be amended or supplemented from time to time. We will issue the senior debt securities in one or more series under our indenture dated as of December 1, 2001, as amended and supplemented, which we refer to as the “senior indenture”, between us and The Bank of New York Mellon Trust Company, N.A., as successor senior trustee. We will issue the subordinated debt securities in one or more series under a subordinated indenture between us and a trustee. The senior indenture, the form of the subordinated indenture and the form of supplemental indenture or other instrument establishing the debt securities of a particular series are exhibits to, or will be subsequently incorporated by reference into, the registration statement of which this prospectus is a part. Each indenture will be qualified under the Trust Indenture Act of 1939. The following summaries of certain provisions of the senior indenture, the subordinated indenture and the applicable debt securities do not purport to be complete and are subject to, and qualified in their entirety by, all provisions of the senior indenture or the subordinated indenture, as the case may be, and the applicable debt securities. We may also sell hybrid or novel securities now existing or developed in the future that combine certain features of the debt securities and other securities described in this prospectus.

Ranking

The senior debt securities will be our direct unsecured general obligations and will rank equally in right of payment with all of our other unsecured and unsubordinated debt. The subordinated debt securities will be our direct unsecured general obligations and will be junior in right of payment to our Senior Indebtedness, as described under the heading “—Subordination of Subordinated Debt Securities.”

Ameren is a holding company that derives substantially all of its income from its operating subsidiaries. As a result, our cash flows and consequent ability to service our debt, including the debt securities, are dependent upon the earnings of our subsidiaries and distribution of those earnings to us and other payments or distributions of funds by our subsidiaries to us, including payments of principal and interest under intercompany indebtedness. Our operating subsidiaries are separate and distinct legal entities and will have no obligation, contingent or otherwise, to pay any dividends or make any other distributions (except for payments required pursuant to the terms of intercompany borrowing arrangements) to us or to otherwise pay amounts due with respect to the debt securities or to make specific funds available for such payments. Various financing arrangements, charter provisions and regulatory requirements may impose certain restrictions on the ability of our subsidiaries to transfer funds to us in the form of cash dividends, loans or advances. Furthermore, except to the extent we have a priority or equal claim against our subsidiaries as a creditor, the debt securities will be effectively subordinated to debt and preferred stock at the subsidiary level because, as the common shareholder of our subsidiaries, we will be subject to the prior claims of creditors and preferred stockholders of our subsidiaries. Unless otherwise described in the applicable prospectus supplement, neither indenture described above limits or will limit the aggregate amount of debt, including secured debt, we or our subsidiaries may incur.

The senior indenture provides, and the subordinated indenture will provide, that our obligations to compensate the applicable trustee and reimburse the applicable trustee for expenses, disbursements and advances will constitute indebtedness which will be secured by a lien generally prior to that of the debt securities upon all property and funds held or collected by the applicable trustee as such.

Subordination of Subordinated Debt Securities

The subordinated debt securities will be subordinate and junior in right of payment to all of our Senior Indebtedness. The term “Senior Indebtedness” will be defined in the applicable prospectus supplement.

No payment of principal of (including redemption and sinking fund payments), premium, if any, or interest on the subordinated debt securities may be made if any Senior Indebtedness is not paid when due, any applicable

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grace period with respect to such default has ended and such default has not been cured or waived, or the maturity of any Senior Indebtedness has been accelerated because of a default and such acceleration has not been rescinded or annulled. If provided in the applicable prospectus supplement, limited subordination periods may apply in the event of non-payment defaults relating to Senior Indebtedness in situations where there has not been an acceleration of Senior Indebtedness.

Upon any distribution of our assets to creditors upon any dissolution, winding-up, liquidation or reorganization, whether voluntary or involuntary, or in bankruptcy, insolvency, receivership or other proceedings, all principal of, and premium, if any, and interest due or to become due on, all Senior Indebtedness must be paid in full before the holders of the subordinated debt securities are entitled to receive or retain any payment. The rights of the holders of the subordinated debt securities will be subrogated to the rights of the holders of Senior Indebtedness to receive payments or distributions applicable to Senior Indebtedness until all amounts owing on the subordinated debt securities are paid in full.

Issuance of Additional Debt Securities

The senior indenture provides, and the subordinated indenture will provide, that additional debt securities may be issued thereunder without limitation as to aggregate principal amount. We may issue one or more series of debt securities directly to the public or as part of a stock purchase unit from time to time.

Provisions of a Particular Series

The prospectus supplement applicable to each series of debt securities will specify:

Unless otherwise indicated in the applicable prospectus supplement, the debt securities will be denominated in United States currency in minimum denominations of $1,000 and integral multiples thereof.

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There is no requirement under the senior indenture, nor will there be any requirement under our subordinated indenture, that our future issuances of debt securities be issued exclusively under the senior indenture or the subordinated indenture, and we will be free to employ other indentures or documentation containing provisions different from those included in the senior indenture or the subordinated indenture applicable to one or more issuances of debt securities, in connection with future issuances of other debt securities.

The senior indenture provides, and the subordinated indenture will provide, that the applicable debt securities will be issued in one or more series, may be issued at various times, may have differing maturity dates, may have differing redemption provisions and may bear interest at differing rates. We need not issue all debt securities of one series at the same time and, unless otherwise provided in the applicable prospectus supplement, we may reopen a series, without the consent of the holders of the debt securities of that series, for issuances of additional debt securities of that series.

Unless otherwise provided in the applicable prospectus supplement, there will be no provisions in either indenture or the related debt securities that require us to redeem, or permit the holders to cause a redemption of, the debt securities or that otherwise protect the holders in the event that we incur substantial additional indebtedness, whether or not in connection with a change in control, or grant security for other of our indebtedness.

Registration, Transfer and Exchange

Unless otherwise indicated in the applicable prospectus supplement, each series of debt securities, will initially be issued in the form of one or more global securities, in registered form, without coupons, as described under “Book-Entry System.” The global securities will be registered in the name of a nominee of The Depository Trust Company, as depository, which we refer to as “DTC,” and deposited with, or on behalf of, the depository. Except as set forth under “Book-Entry System,” owners of beneficial interests in a global security will not be entitled to have debt securities registered in their names, will not receive or be entitled to receive physical delivery of any debt securities and will not be considered the registered holders thereof under the applicable indenture.

Debt securities of any series will be exchangeable for other debt securities of the same series of any authorized denominations and of a like aggregate principal amount and tenor.

Unless otherwise indicated in the applicable prospectus supplement, debt securities may be presented for exchange or registration of transfer—duly endorsed or accompanied by a duly executed written instrument of transfer—at the office of the applicable trustee maintained for such purpose with respect to any series of debt securities, without service charge but upon payment of any taxes and other governmental charges as described in the applicable indenture. Such transfer or exchange will be effected upon the applicable trustee and us being satisfied with the endorsements or instruments of transfer and the identity or authorization of the person making the request. In the case of any debt securities that have been mutilated, destroyed, lost or stolen, new debt securities of a like aggregate principal amount and tenor will be issued upon the applicable trustee and us being satisfied with the evidence of ownership and loss and with the security or indemnity provided.

In the event of any redemption of debt securities of any series, the applicable trustee will not be required to exchange or register a transfer of any debt securities of such series selected, called or being called for redemption except, in the case of any debt security to be redeemed in part, the portion thereof not to be so redeemed.

Payment and Paying Agents

Payments with respect to principal of, premium, if any, and interest on debt securities issued in the form of global securities will be paid in the manner described below under “Book-Entry System.”

Unless otherwise indicated in the applicable prospectus supplement, interest on debt securities, other than interest at maturity, that are in the form of certificated securities will be paid by check payable in clearinghouse

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funds mailed to the person entitled thereto at such person’s address as it appears in the register for the debt securities maintained by the applicable trustee; provided, however, a holder of debt securities in the aggregate principal amount of $10,000,000 or more having the same interest payment dates will be entitled to receive payments of interest on such series by wire transfer of immediately available funds to a bank within the continental United States if the trustee has received appropriate wire transfer instructions on or prior to the applicable regular record date for such interest payment date. Unless otherwise indicated in the applicable prospectus supplement, the principal of, premium, if any, and interest at maturity on, debt securities in the form of certificated securities will be payable in immediately available funds at the office of the applicable trustee or at the authorized office of any paying agent or paying agents upon presentation and surrender of such debt securities. We may appoint additional paying agents from time to time, including ourselves or our affiliates.

All monies we pay to a trustee or a paying agent for the payment of principal of, premium, if any, and interest on any debt security which remain unclaimed at the end of two years after such principal, premium or interest shall have become due and payable will be repaid to us, subject to applicable abandoned property laws, and the holder of such debt security thereafter may look only to us for payment thereof.

In any case where the date on which the principal of, premium, if any, or interest on any debt security is due or the date fixed for redemption of any debt security is not a business day (as defined in the applicable indenture), then payment of that principal, premium or interest need not be made on such date but may be made on the next succeeding business day with the same force and effect as if made on the due date or the date fixed for redemption, and, in the case of timely payment on such business day, no additional interest shall accrue for the period from and after such principal, premium or interest is stated to be due to such business day.

Redemption Provisions

Any terms for the optional or mandatory redemption of the debt securities will be indicated in the applicable prospectus supplement. Unless otherwise indicated in the applicable prospectus supplement, the debt securities will be redeemable only upon notice by mail not less than 30 nor more than 60 days prior to the date fixed for redemption, and, if less than all the debt securities of a series are to be redeemed, the particular debt securities to be redeemed will be selected by the applicable trustee in such manner as it shall deem appropriate and fair.

Any notice of redemption at our option may state that such redemption will be conditional upon receipt by the trustee or the paying agent or agents, on or prior to the date fixed for such redemption, of money sufficient to pay the principal of, premium, if any, and interest on such debt securities and that if such money has not been so received, such notice will be of no force and effect and we will not be required to redeem such debt securities.

Events of Default

The following constitute or will constitute events of default under the applicable indenture with respect to the debt securities of any series:

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No event of default with respect to the debt securities of a particular series necessarily constitutes an event of default with respect to the debt securities of any other series issued under the applicable indenture. If provided in the applicable prospectus supplement, an event of default similar to the event of default described in the fourth bullet above may be applicable to a series of subordinated debt securities.

If an event of default with respect to any series of debt securities occurs and is continuing, either the trustee for such series or the holders of a majority in aggregate principal amount of the outstanding debt securities of such series may declare, by notice in writing, the principal amount of and interest on all debt securities of such series to be due and payable immediately; provided, however, that if an event of default occurs and is continuing with respect to more than one series of debt securities under a particular indenture, the trustee for such series or the holders of a majority in aggregate principal amount of the outstanding debt securities of all such series, considered as one class, may make such declaration of acceleration and not the holders of the debt securities of any one of such series.

At any time after an acceleration of the debt securities of any series has been declared, but before a judgment or decree for the payment of the principal amount of the debt securities has been obtained, if we pay or deposit with the applicable trustee a sum sufficient to pay all matured installments of interest and the principal and premium, if any, which has become due otherwise than by acceleration and any amounts due to the applicable trustee, and all defaults shall have been cured or waived, then such payment or deposit will cause an automatic rescission and annulment of the acceleration of the debt securities.

The senior indenture provides, and the subordinated indenture will provide that the applicable trustee generally will be under no obligation to exercise any of its rights or powers under the indenture at the request or direction of any of the holders of debt securities unless such holders have offered to the applicable trustee reasonable security or indemnity. Subject to such provisions for indemnity and certain other limitations contained in the applicable indenture, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or of exercising any trust or power conferred on the trustee, with respect to the debt securities of that series; provided, however, that if an event of default occurs and is continuing with respect to more than one series of debt securities, the holders of a majority in aggregate principal amount of the outstanding debt securities of all those series, considered as one class, will have the right to make such direction, and not the holders of the debt securities of any one series.

The holders of a majority in principal amount of the outstanding debt securities of any series generally will have the right to waive any past default or event of default under the applicable indenture on behalf of all holders

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of debt securities of that series with respect to the debt securities of that series, except a default in the payment of principal of, premium, if any, or interest on such debt securities. The applicable indenture provides or will provide that no holder of debt securities of any series may institute any action against us under the applicable indenture except as described in the next paragraph or unless such holder previously shall have given to the trustee for such series written notice of default and continuance thereof with respect to the debt securities of such series and unless the holders of not less than a majority in aggregate principal amount of the debt securities of all series in respect of which an event of default has occurred and is continuing, considered as one class, shall have requested the trustee for such series to institute such action and shall have offered that trustee reasonable indemnity, and the trustee for such series shall not have instituted such action within 60 days of such request. Furthermore, no holder of debt securities of any series will be entitled to institute any such action if and to the extent that such action would disturb or prejudice the rights of other holders of those debt securities.

Notwithstanding the foregoing, each holder of debt securities of any series has the right, which is absolute and unconditional, to receive payment of the principal of, premium, if any, and interest on such debt securities when due and to institute suit for the enforcement of any such payment, and such rights may not be impaired without the consent of that holder of debt securities.

The senior indenture provides, and the subordinated indenture will provide, that the applicable trustee, within 90 days after the occurrence of a default with respect to the debt securities of any series actually known to the applicable trustee, is required to give the holders of the debt securities of that series notice of such default, unless cured or waived, but, except in the case of default in the payment of principal of, premium or interest on any debt securities of that series, the trustee may withhold such notice if it determines in good faith that it is in the interest of such holders to do so. We are and will be required to deliver to the senior trustee and the subordinated trustee each year a certificate as to whether or not, to the knowledge of the officer signing such certificate, we are in compliance with the conditions and covenants under the applicable indenture.

Modification

The applicable trustee and we may modify and amend the indenture with the consent of the holders of a majority in principal amount of the debt securities of all series under that indenture directly affected by such modification or amendment, considered as one class, provided that no such modification or amendment may, without the consent of the holder of each outstanding debt security affected thereby:

The applicable trustee and we may modify and amend the indenture without the consent of the holders:

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A supplemental indenture which changes or eliminates any covenant or other provision of the applicable indenture (or any supplemental indenture) which has expressly been included solely for the benefit of one or more series of debt securities, or which modifies the rights of the holders of debt securities of such series with respect to such covenant or provision, will be deemed not to affect the rights under the applicable indenture of the holders of debt securities of any other series.

Defeasance and Discharge

The senior indenture provides, and the subordinated indenture will provide, that we will

In the case of either (1) or (2), we are required to deposit, in trust, with the applicable trustee money or U.S. government obligations, which through the payment of interest on those obligations and principal of those obligations in accordance with their terms will provide money, in an amount sufficient, without reinvestment, to pay all the principal of, premium, if any, and interest on the debt securities of such series on the dates payments are due (which may include one or more redemption dates designated by us). This trust may only be established if, among other things, (A) no event of default or event which with the giving of notice or lapse of time, or both, would become an event of default under the applicable indenture has occurred and is continuing on the date of the deposit, (B) the deposit will not cause the trustee to have any conflicting interest with respect to our other securities and (C) we have delivered an opinion of counsel to the effect that the holders will not recognize income, gain or loss for federal income tax purposes (and, in the case of paragraph (1) above, such opinion of

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counsel is based on a ruling of the Internal Revenue Service or other change in applicable federal income tax law) as a result of the deposit or defeasance and will be subject to federal income tax in the same amounts, in the same manner and at the same times as if the deposit and defeasance had not occurred.

We may be discharged under paragraph (1) with respect to debt securities of any series notwithstanding our prior release under paragraph (2). If we exercise our discharge option for debt securities of any series, payment of the debt securities of such series may not be accelerated because of a subsequent event of default. If we exercise our release option for debt securities of any series, payment of the debt securities of such series may not be accelerated by reference to a subsequent breach of any of the covenants noted under clause (2) in the preceding paragraph. In the event we omit to comply with our remaining obligations with respect to the debt securities of any series under the applicable indenture after exercising our release option and the debt securities of such series are declared due and payable because of the subsequent occurrence of any event of default, the amount of money and U.S. government obligations on deposit with the trustee may be insufficient to pay amounts due on the debt securities of such series at the time of the acceleration resulting from that event of default. However, we will remain liable for those payments.

Consolidation, Merger and Sale or Disposition of Assets

We have agreed not to consolidate with or merge into any other corporation or sell or otherwise dispose of our properties substantially as an entirety to any person unless:

Upon any such consolidation, merger, sale or other disposition of our properties substantially as an entirety, the successor corporation formed by such consolidation or into which we are merged or the person to which such sale or other disposition is made shall succeed to, and be substituted for, and may exercise every right and power of, us under the applicable indenture with the same effect as if such successor corporation or person had been named as us therein and we will be released from all obligations under the applicable indenture.

Resignation or Removal of Trustees

A trustee may resign at any time upon written notice to us specifying the day upon which the resignation is to take effect and such resignation will take effect immediately upon the later of the appointment of a successor trustee and such specified day. The trustee may be removed at any time with respect to debt securities of any series by an instrument or concurrent instruments in writing filed with the trustee and signed by the holders, or their attorneys-in-fact, of a majority in principal amount of such series of debt securities then outstanding. In addition, so long as no event of default or event which, with the giving of notice or lapse of time or both, would become an event of default has occurred and is continuing, we may remove a trustee upon notice to the holder of each debt security outstanding under the applicable indenture and the trustee, and appointment of a successor trustee.

Concerning the Senior Trustee

We and our affiliates maintain corporate trust and other banking relationships with The Bank of New York Mellon Trust Company, N.A. and its affiliates.

Governing Law

The senior indenture is, and the subordinated indenture and the related debt securities will be, governed by New York law.

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DESCRIPTION OF COMMON STOCK

General

The following statements describing common stock of Ameren are not intended to be a complete description but rather are a summary of certain rights and distinguishing characteristics relating to the common stock currently authorized by our Restated Articles of Incorporation, as amended (“articles of incorporation”). For additional information, please see our articles of incorporation and bylaws. Each of these documents has been previously filed with the SEC and each is an exhibit to the registration statement filed with the SEC of which this prospectus is a part. Reference is also made to the laws of the state of Missouri.

Under our articles of incorporation, we are authorized to issue 400,000,000 shares of common stock, $0.01 par value per share, and 100,000,000 shares of preferred stock, $0.01 par value per share.

Dividend Rights and Limitations

The holders of our common stock are entitled to receive such dividends as our board of directors may from time to time declare, subject to any rights of the holders of our preferred stock, if any is issued. Our ability to pay dividends depends primarily upon the ability of our subsidiaries to pay dividends or otherwise transfer funds to us. Various financing arrangements, charter provisions and regulatory requirements may impose certain restrictions on the ability of our subsidiaries to transfer funds to us in the form of cash dividends, loans or advances.

Voting Rights

Except as otherwise provided by law and subject to the voting rights of holders of our preferred stock, if any is issued, the holders of our common stock have the exclusive right to vote for the election of directors and for all other purposes. Each holder of our common stock is entitled to one vote per share on all matters submitted to a vote at a meeting of shareholders, including the election of directors, which means that the holders of more than 50% of the shares voting for the election of directors can elect 100% of the directors and the holders of the remaining shares voting for the election of directors will not be able to elect any directors. The common stock shall vote together as a single class. The holders of our common stock are not entitled to cumulate votes for the election of directors. At annual and special meetings of shareholders, a majority of the outstanding shares of common stock constitutes a quorum.

Liquidation Rights

In the event of any liquidation, dissolution or winding up of our affairs, voluntarily or involuntarily, the holders of our common stock will be entitled to receive the remainder, if any, of our assets after the payment of all our debts and liabilities and after the payment in full of any preferential amounts to which holders of any preferred stock may be entitled.

Uncertificated Shares and Certificates of Stock

The interest of each shareholder of any class of our stock shall not be evidenced by certificates for shares and all shares of all classes of stock shall be uncertificated shares; provided, however, that (a) any shares of our stock represented by a certificate shall continue to be represented by such certificate until such certificate is surrendered to us and (b) we may, at our option but without obligation, issue certificates for some or all of any shares of some or all of any classes of stock as we determine from time to time.

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Miscellaneous

The outstanding shares of common stock are, and any shares of common stock sold hereunder will be, upon payment for them, fully paid and nonassessable. The holders of our common stock are not entitled to any preemptive or preferential rights to subscribe for or purchase any part of any new or additional issue of stock or securities convertible into stock. Our common stock does not contain any redemption provisions or conversion rights.

DESCRIPTION OF PREFERRED STOCK

General

The following statements describing preferred stock of Ameren are not intended to be a complete description but rather are a summary of certain preferences, privileges, restrictions and distinguishing characteristics relating to the preferred stock currently authorized by our articles of incorporation. For additional information, please see our articles of incorporation and bylaws. Each of these documents has been previously filed with the SEC and each is an exhibit to the registration statement filed with the SEC of which this prospectus is a part. Reference is also made to the laws of the state of Missouri. The other terms and provisions of each series of preferred stock (as defined below) will be set forth in the resolution adopted by our board of directors establishing such series of preferred stock and will be described in the prospectus supplement relating to such offering.

Our authorized preferred stock consists of 100,000,000 shares of preferred stock, $0.01 par value per share. When used in this prospectus, the term “preferred stock,” unless the context indicates otherwise, means all the authorized shares of our preferred stock, whether currently outstanding or hereafter issued.

The following terms and other information with respect to any series of preferred stock will be contained in a prospectus supplement:

Issuance in Series; Rank

The authorized but unissued shares of preferred stock may be issued in one or more series from time to time upon such terms and in such manner, with such variations as to dividend rates (which may be fixed or variable), dividend periods and payment dates, the prices at which, and the terms and conditions on which, shares may be redeemed or repurchased, and sinking fund provisions, if any, as may be determined by our board of directors. Except for such characteristics, as to which our board of directors has discretion, and as otherwise provided in the applicable prospectus supplement, all series of the preferred stock rank equally and are alike in all respects.

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Unless otherwise provided in the applicable prospectus supplement, our preferred stock will rank senior with respect to dividends and liquidation rights to our common stock, $0.01 par value (“common stock”).

Dividend Rights

Each series of preferred stock will have the dividend rights described in the applicable prospectus supplement.

Optional Redemption Provisions

Each series of preferred stock will have the redemption provisions described in the applicable prospectus supplement.

Voting Rights

Except as provided by law or in the applicable prospectus supplement, holders of preferred stock will not be entitled to vote for the election of directors or for any other purpose. Under Missouri law holders of the preferred stock have the right to vote as a class on any amendment to our articles of incorporation that would increase or decrease the number of authorized shares of the preferred stock, increase or decrease the par value of the preferred stock, create a new class of shares senior to the preferred stock, increase the rights and preferences or the number of authorized shares of any class of shares senior to the preferred stock, or adversely affect the preferred stock’s preferences or special or relative rights, but if less than all series of a class are adversely affected, then the affected series have the right to vote as a class on such amendment.

Liquidation Rights

Each series of preferred stock will have the liquidation rights described in the applicable prospectus supplement.

Restrictions on Certain Corporate Actions

Our articles of incorporation and by-laws include a number of provisions that may have the effect of discouraging persons from acquiring large blocks of our stock or delaying or preventing a change in our control. See “Description of Common Stock—Certain Anti-Takeover Matters.”

Preemptive Rights

Holders of the preferred stock have no preemptive rights to subscribe for or purchase any securities issued by us.

Miscellaneous

Shares of preferred stock, when issued by us upon receipt of the consideration therefor, will be fully paid and non-assessable.

Transfer Agent and Registrar

Ameren Services Company serves as transfer agent and registrar for our preferred stock.

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DESCRIPTION OF STOCK PURCHASE CONTRACTS AND STOCK PURCHASE UNITS

We may issue stock purchase contracts, including contracts obligating holders to purchase from us, and us to sell to the holders, a specified number of shares of our common stock at a future date or dates. The price per share of common stock and the number of shares of common stock may be fixed at the time the stock purchase contracts are issued or may be determined by reference to a specific formula set forth in the stock purchase contracts. The stock purchase contracts may be issued separately or as part of units, often known as stock purchase units, consisting of a stock purchase contract and beneficial interests in:

securing the holders’ obligations to purchase the common stock under the stock purchase contracts. The stock purchase contracts may require us to make periodic payments to the holders of the stock purchase units or vice versa, and these payments may be unsecured or prefunded on some basis. The stock purchase contracts may require holders to secure their obligations under those contracts in a specified manner.

The applicable prospectus supplement will describe the terms of the stock purchase contracts or stock purchase units, including, if applicable, collateral or depositary arrangements.

BOOK-ENTRY SYSTEM

Unless otherwise indicated in the applicable prospectus supplement, the securities will initially be issued in the form of one or more global securities, in registered form, without coupons. The global security will be deposited with, or on behalf of, the depository, and registered in the name of the depository or a nominee of the depository. Unless otherwise indicated in the applicable prospectus supplement, the depository for any global securities will be DTC. Global debt securities registered in the name of Cede & Co. may be held by the applicable trustee as custodian for DTC.

So long as the depository, or its nominee, is the registered owner of a global security, such depository or such nominee, as the case may be, will be considered the owner of such global security for all purposes under the applicable indenture, including for any notices and voting. Except in limited circumstances, the owners of beneficial interests in a global security will not be entitled to have securities registered in their names, will not receive or be entitled to receive physical delivery of any such securities and will not be considered the registered holder thereof under the applicable indenture. Accordingly, each person holding a beneficial interest in a global security must rely on the procedures of the depository and, if such person is not a direct participant, on procedures of the direct participant through which such person holds its interest, to exercise any of the rights of a registered owner of such security.

Global securities may be exchanged in whole for certificated securities only if:

In any such case, we have agreed to notify the applicable trustee or agent in writing that, upon surrender by the direct participants and indirect participants of their interest in such global securities, certificated securities representing the applicable securities will be issued to each person that such direct participants and indirect participants and the depository identify as being the beneficial owner of such securities.

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The following is based solely on information furnished by DTC:

DTC is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code, and a “clearing agency” registered pursuant to the provisions of Section 17A of the Securities Exchange Act of 1934. DTC holds and provides asset servicing for U.S. and non-U.S. equity issues, corporate and municipal debt issues and money market instruments that DTC’s participants (“Direct Participants”) deposit with DTC. DTC also facilitates the post-trade settlement among Direct Participants of sales and other securities transactions in deposited securities, through electronic computerized book-entry transfers and pledges between Direct Participants’ accounts. This eliminates the need for physical movement of securities certificates. Direct Participants include both U.S. and non-U.S. securities brokers and dealers, banks, trust companies, clearing corporations, and certain other organizations. DTC is a wholly owned subsidiary of The Depository Trust & Clearing Corporation (“DTCC”). DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others such as both U.S. and non-U.S. securities brokers and dealers, banks, trust companies, and clearing corporations that clear through or maintain a custodial relationship with a Direct Participant, either directly or indirectly (“Indirect Participants”). The DTC Rules applicable to its Participants are on file with the SEC.

Purchases of global securities under the DTC system must be made by or through Direct Participants, which will receive a credit for the global securities on DTC’s records. The ownership interest of each actual purchaser of each security (“Beneficial Owner”) is in turn to be recorded on the Direct and Indirect Participants’ records. Beneficial Owners will not receive written confirmation from DTC of their purchase, but Beneficial Owners are expected to receive written confirmations providing details of the transaction, as well as periodic statements of their holdings, from the Direct or Indirect Participant through which the Beneficial Owner entered into the transaction. Transfers of ownership interests in the securities are to be accomplished by entries made on the books of Direct and Indirect Participants acting on behalf of Beneficial Owners. Beneficial Owners will not receive certificates representing their ownership interests in the global securities except in the event that use of the book-entry system for the global securities is discontinued.

To facilitate subsequent transfers, all global securities deposited by Direct Participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co. or such other name as may be requested by an authorized representative of DTC. The deposit of global securities with DTC and their registration in the name of Cede & Co. or such other nominee will effect no change in beneficial ownership. DTC will have no knowledge of the actual Beneficial Owners of the global securities; DTC’s records will reflect only the identity of the Direct Participants to whose accounts such securities are credited, which may or may not be the Beneficial Owners. The Direct and Indirect Participants will remain responsible for keeping account of their holdings on behalf of their customers.

Conveyance of notices and other communications by DTC to Direct Participants, by Direct Participants to Indirect Participants, and by Direct Participants and Indirect Participants to Beneficial Owners will be governed by arrangements among them, subject to any statutory or regulatory requirements as may be in effect from time to time. Beneficial Owners may wish to take certain steps to augment transmission to them of notices of significant events with respect to the global securities, such as redemptions, tenders, defaults and proposed amendments to the Indenture. Beneficial Owners may wish to ascertain that the nominee holding the global securities for their benefit has agreed to obtain and transmit notices to the Beneficial Owners. In the alternative, Beneficial Owners may wish to provide their names and addresses to the registrar and request that copies of notices be provided directly to them.

Any redemption notices will be sent to DTC. If less than all of a series of global securities are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each Direct Participant to be redeemed.

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Neither DTC nor Cede & Co. (nor any other DTC nominee) will consent or vote with respect to securities unless authorized by a Direct Participant in accordance with DTC’s procedures. Under its usual procedures, DTC mails an Omnibus Proxy (the “Omnibus Proxy”) to us as soon as possible after the record date. The Omnibus Proxy assigns Cede & Co.’s consenting or voting rights to those Direct Participants to whose accounts the securities are credited on the record date (identified in a listing attached to the Omnibus Proxy).

Principal and interest payments, distributions and dividend payments and redemption proceeds, if any, on the global securities will be made to Cede & Co. or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit Direct Participants’ accounts upon DTC’s receipt of funds and corresponding detail information from the trustee or agent on the payment date in accordance with their respective holdings shown on DTC’s records. Payments by Direct and Indirect Participants to Beneficial Owners will be governed by standing instructions and customary practices, as is the case with securities held for the accounts of customers in bearer form or registered in “street-name,” and will be the responsibility of such Participants and not of DTC, the trustee or agent for such securities or us, subject to any statutory or regulatory requirements as may be in effect from time to time. Payment of principal, premium, if any, interest, distributions and dividend payments and redemption proceeds, if any, to Cede & Co. (or such other nominee as may be requested by an authorized representative of DTC) is the responsibility of the appropriate trustee or agent and us, disbursement of such payments to Direct Participants is the responsibility of DTC, and disbursement of such payments to the Beneficial Owners is the responsibility of Direct and Indirect Participants.

The information in this section concerning DTC and DTC’s book-entry system has been obtained from sources, including DTC, that we believe to be reliable, but we take no responsibility for the accuracy thereof.

The underwriters, dealers or agents of any of the securities may be direct participants of DTC.

None of the trustees, us or any agent for payment on or registration of transfer or exchange of any global security will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial interests in such global security or for maintaining, supervising or reviewing any records relating to such beneficial interests.

DESCRIPTION OF SENIOR SECURED DEBT SECURITIES

General

The senior secured debt securities will be issued under, and secured by, our senior secured indenture dated as of August 15, 2002, as amended and supplemented, which we refer to collectively as the “senior secured indenture,” between The Bank of New York Mellon, as senior secured trustee, and us. The senior secured indenture and the form of supplemental indenture or other instrument establishing the senior secured debt securities of a particular series are exhibits to, or will be subsequently incorporated by reference into, the registration statement of which this prospectus is a part. The senior secured indenture has been qualified under the Trust Indenture Act of 1939. The senior secured debt securities of all series that may be issued under the senior secured indenture are referred to under this caption as “senior secured debt securities.” The following summaries of certain provisions of the senior secured indenture do not purport to be complete and are subject to, and qualified in their entirety by, all provisions of the senior secured indenture and the senior secured debt securities.

Priority and Security; Release Date

Until the release date (as defined below), all of the senior secured debt securities outstanding under the senior secured indenture will be secured by one or more series of our first mortgage bonds, which we refer to as the “senior note mortgage bonds,” issued under the mortgage indenture described under “Description of First Mortgage Bonds and Mortgage Indenture” and delivered by us to the senior secured trustee. On the date of original issuance of a series of senior secured debt securities before the release date, we will simultaneously issue and deliver to the senior secured trustee under the senior secured indenture, as security for such senior secured debt securities, a corresponding series of our senior note mortgage bonds. Each series of senior note mortgage bonds will be in the same aggregate principal amount, will have the same stated maturity date and redemption provisions, and if they bear interest, will have the same interest rate and interest payment dates, as the series of such senior secured debt securities to which they relate. These senior note mortgage bonds will secure the related series of senior secured debt securities. Until the release date, the senior secured debt securities will be secured ratably with our first mortgage bonds in the collateral pledged to secure such bonds.

When we pay the principal of, premium, if any, and interest on the senior secured debt securities, senior note mortgage bonds of the related series in a principal amount equal to the principal amount of such senior secured debt securities so paid will be deemed fully paid and our obligation to make such payment shall be discharged. Any payment of principal of, premium, if any, and interest on each series of senior note mortgage bonds will generally be applied by the senior secured trustee to satisfy our obligations with respect to principal of, premium, if any, and interest on the related series of senior secured debt securities.

The release date will be the date that all of our first mortgage bonds issued and outstanding under the mortgage indenture, other than the senior note mortgage bonds, have been retired—at, before or after the maturity thereof—through payment, redemption or otherwise, including those first mortgage bonds deemed to be paid within the meaning of the mortgage indenture. On the release date, the senior secured trustee will deliver to us for cancellation all the senior note mortgage bonds and, not later than 30 days thereafter, will provide notice to all holders of senior secured debt securities of the occurrence of the release date. As a result, on the release date, the senior note mortgage bonds shall cease to secure the senior secured debt securities, and the senior secured debt securities will become our unsecured general obligations and will rank equally with all of our other unsecured and unsubordinated debt from time to time outstanding, unless otherwise secured as described in this prospectus or any prospectus supplement.

We have agreed that so long as any of our 8.45% Senior Secured Notes due 2039, 6.70% Senior Secured Notes due 2019 and 6.00% Senior Secured Notes due 2018 are outstanding, we will not optionally redeem, purchase or otherwise retire in full our outstanding first mortgage bonds not subject to release provisions. We have one outstanding series of first mortgage bonds which is not subject to release

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provisions, a 5.45% series in the principal amount of $44 million due in October 2028 (securing environmental improvement indebtedness) that may be redeemed at any time at a redemption price of 100% of the principal amount. We have four other outstanding series of first mortgage bonds maturing in 2022 and 2033 (securing environmental improvement indebtedness) that will cease to secure such indebtedness on the release date. We have also agreed that so long as any of our 6.40% Senior Secured Notes due 2017 are outstanding, we will not, prior to June 15, 2012, optionally redeem, purchase or otherwise retire in full our outstanding first mortgage bonds not subject to release provisions. We may at any time redeem our 8.45% Senior Secured Notes due 2039, 6.70% Senior Secured Notes due 2019, 6.00% Senior Secured Notes due 2018 or 6.40% Senior Secured Notes due 2017 at a make-whole redemption price.

Until the release date, the senior secured debt securities will rank equally with all of our other current and future secured debt that is directly or indirectly secured by the lien of the mortgage indenture, will be effectively senior to our unsecured and unsubordinated debt (with respect to the mortgaged property under the mortgage indenture as defined below under “Description of First Mortgage Bonds and Mortgage Indenture—Priority and Security”) and will rank senior in right of payment to our subordinated debt.

Each series of senior note mortgage bonds will be a series of our first mortgage bonds, all of which are secured by a lien on the mortgaged property. Upon the payment or cancellation of any outstanding senior secured debt securities, the senior secured trustee shall surrender to us for cancellation an equal principal amount of the related series of senior note mortgage bonds. We have agreed not to permit, at any time prior to the release date, the aggregate principal amount of senior note mortgage bonds held by the senior secured trustee to be less than the aggregate principal amount of senior secured debt securities then outstanding under the senior secured indenture. Prior to the release date, we may continue to issue first mortgage bonds under the mortgage indenture and such first mortgage bonds may not be subject to release provisions. Following the release date, we have agreed to cause the mortgage indenture to be discharged and we have agreed not to issue any additional first mortgage bonds under the mortgage indenture. While we have agreed to be precluded after the release date from issuing additional first mortgage bonds under the mortgage indenture, we have not agreed to be precluded under the senior secured indenture from issuing or assuming other secured or unsecured debt, or incurring liens on our property, except to the extent indicated under “—Certain Covenants—Limitation on Liens” and “—Certain Covenants—Limitation on Sale and Lease-Back Transactions,” and except as may otherwise be indicated in the applicable prospectus supplement. The senior secured debt securities can become secured by certain of our property from and after the release date as explained below under “—Certain Covenants—Limitation on Liens.”

The senior secured indenture provides that our obligations to compensate the senior secured trustee and reimburse the senior secured trustee for expenses, disbursements and advances will constitute indebtedness which will be secured by a lien generally prior to that of the senior secured debt securities upon all property and funds held or collected by the senior secured trustee as such.

Issuance of Additional Senior Secured Debt Securities

The senior secured indenture provides that senior secured debt securities may be issued thereunder, without limitation as to aggregate principal amount, provided that, prior to the release date, the principal amount of senior secured debt securities that may be issued and outstanding under the senior secured indenture cannot exceed the principal amount of senior note mortgage bonds then held by the senior secured trustee under the senior secured indenture.

Provisions of a Particular Series

The prospectus supplement applicable to each series of senior secured debt securities will specify:

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Unless otherwise indicated in the applicable prospectus supplement, the senior secured debt securities will be denominated in United States currency in minimum denominations of $1,000 and integral multiples thereof.

There is no requirement under the senior secured indenture that our future issuances of debt securities be issued exclusively under the senior secured indenture, and we will be free to employ other indentures or documentation containing provisions different from those included in the senior secured indenture or applicable to one or more issuances of senior secured debt securities, in connection with future issuances of other debt securities, including as described in this prospectus under “Description of Senior Unsecured Debt Securities.”

The senior secured indenture provides that the senior secured debt securities will be issued in one or more series, may be issued at various times, may have differing maturity dates, may have differing redemption provisions and may bear interest at differing rates. We need not issue all senior secured debt securities of one series at the same time, and, unless otherwise provided in the applicable prospectus supplement, we may reopen a series without the consent of the holders of the senior secured debt securities of that series, for issuances of additional senior secured debt securities of that series.

Unless otherwise provided in the applicable prospectus supplement, there are no provisions in the senior secured indenture or the senior secured debt securities that require us to redeem, or permit the holders to cause a redemption of, the senior secured debt securities or, except for the requirement that existing and additional senior secured debt securities be secured by an equal principal amount of senior note mortgage bonds until a release date occurs as described under “—Priority and Security; Release Date” and “—Issuance of Additional Senior Secured Debt Securities,” that otherwise protect the holders in the event that we incur substantial additional indebtedness, whether or not in connection with a change in control.

Registration, Transfer and Exchange

Unless otherwise indicated in the applicable prospectus supplement, each series of senior secured debt securities will initially be issued in the form of one or more global securities, in registered form, without coupons, as described under “Book-Entry System.” The global securities will be registered in the name of a nominee of The Depository Trust Company, as depository, which we refer to as “DTC,” and deposited with, or on behalf of, the depository. Except as set forth under “Book-Entry System,” owners of beneficial interests in a global security will not be entitled to have senior secured debt securities registered in their names, will not receive or be entitled to receive physical delivery of any senior secured debt securities and will not be considered the registered holders thereof under the senior secured indenture.

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Senior secured debt securities of any series will be exchangeable for other senior secured debt securities of the same series of any authorized denominations and of a like aggregate principal amount and tenor. Unless otherwise indicated in the applicable prospectus supplement, senior secured debt securities may be presented for exchange or registration of transfer—duly endorsed or accompanied by a duly executed written instrument of transfer—at the office of the senior secured trustee maintained for such purpose with respect to any series of senior secured debt securities, without service charge but upon payment of any taxes and other governmental charges as described in the senior secured indenture. Such transfer or exchange will be effected upon the senior secured trustee and us being satisfied with the endorsements or instruments of transfer and the identity or authorization of the person making the request. In the case of any senior secured debt securities that have been mutilated, destroyed, lost or stolen, new senior secured debt securities of a like aggregate principal amount and tenor will be issued upon the senior secured trustee and us being satisfied with the evidence of ownership and loss and with the security or indemnity provided.

In the event of any redemption of senior secured debt securities of any series, the senior secured trustee will not be required to exchange or register a transfer of any senior secured debt securities of such series selected, called or being called for redemption except, in the case of any senior secured debt security to be redeemed in part, the portion thereof not to be so redeemed.

Payment and Paying Agents

Payments with respect to principal of, premium, if any, and interest on senior secured debt securities issued in the form of global securities will be paid in the manner described below under “Book-Entry System.”

Unless otherwise indicated in the applicable prospectus supplement, interest on senior secured debt securities, other than interest at maturity, that are in the form of certificated securities will be paid by check payable in clearinghouse funds mailed to the person entitled thereto at such person’s address as it appears in the register for the senior secured debt securities maintained by the senior secured trustee; provided, however, a holder of senior secured debt securities of one or more series under the senior secured indenture in the aggregate principal amount of $10,000,000 or more having the same interest payment dates will be entitled to receive payments of interest on such series by wire transfer of immediately available funds to a bank within the continental United States if the senior secured trustee has received appropriate wire transfer instructions on or prior to the applicable regular record date for such interest payment date. Unless otherwise indicated in the applicable prospectus supplement, the principal of, premium, if any, and interest at maturity on, senior secured debt securities in the form of certificated securities will be payable in immediately available funds at the office of the senior secured trustee or at the authorized office of any paying agent upon presentation and surrender of such senior secured debt securities. We may appoint additional paying agents from time to time, including ourselves or our affiliates.

All monies we pay to the senior secured trustee for the payment of principal of, premium, if any, and interest on any senior secured debt security which remain unclaimed at the end of two years after such principal, premium or interest shall have become due and payable will be repaid to us, subject to applicable abandoned property laws, and the holder of such senior secured debt security thereafter may look only to us for payment thereof.

In any case where the date on which the principal of, premium, if any, or interest on any senior secured debt security is due or the date fixed for redemption of any senior secured debt security is not a business day (as defined in the senior secured indenture), then payment of that principal, premium or interest need not be made on such date but may be made on the next succeeding business day with the same force and effect as if made on the due date or the date fixed for redemption, and, in the case of timely payment on such business day, no additional interest shall accrue for the period from and after such principal, premium or interest is stated to be due to such business day.

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Redemption Provisions

Any terms for the optional or mandatory redemption of the senior secured debt securities will be indicated in the applicable prospectus supplement. Unless otherwise indicated in the applicable prospectus supplement, the senior secured debt securities will be redeemable only upon notice by mail not less than 30 nor more than 60 days prior to the date fixed for redemption, and, if less than all the senior secured debt securities of a series are to be redeemed, the particular senior secured debt securities to be redeemed will be selected by the senior secured trustee in such manner as it shall deem appropriate and fair.

Any notice of redemption at our option may state that such redemption will be conditional upon receipt by the senior secured trustee, on or prior to the date fixed for such redemption, of money sufficient to pay the principal of, premium, if any, and interest on such senior secured debt securities and that if such money has not been so received, such notice will be of no force and effect and we will not be required to redeem such senior secured debt securities.

Events of Default

The following constitute events of default under the senior secured indenture with respect to the senior secured debt securities:

If an event of default under the senior secured indenture occurs and is continuing, either the senior secured trustee or the holders of not less than 33% in aggregate principal amount of the outstanding senior secured debt securities may declare, by notice in writing, the principal amount of and interest on all senior secured debt securities to be due and payable immediately. Upon such acceleration of the senior secured debt securities, the senior note mortgage bonds shall be immediately redeemable upon demand of the senior secured trustee, and surrender thereof to the mortgage trustee, at a redemption price of 100% of the principal amount thereof, together with accrued interest to the redemption date. At any time after an acceleration of the senior secured debt securities has been declared, but before a judgment or decree for the payment of the principal amount of the senior secured debt securities has been obtained, and provided the acceleration of all senior note mortgage bonds has not occurred, if we pay or deposit with the senior secured trustee a sum sufficient to pay all matured

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installments of interest and the principal and premium, if any, which has become due otherwise than by acceleration and any amounts due to the senior secured trustee, and all defaults shall have been cured or waived, then such payment or deposit will cause an automatic rescission and annulment of the acceleration of the senior secured debt securities.

The senior secured indenture provides that the senior secured trustee generally will be under no obligation to exercise any of its rights or powers under the senior secured indenture at the request or direction of any of the holders of senior secured debt securities unless such holders have offered to the senior secured trustee reasonable security or indemnity. Subject to such provisions for indemnity and certain other limitations contained in the senior secured indenture, the holders of a majority in principal amount of the outstanding senior secured debt securities generally will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the senior secured trustee, or of exercising any trust or power conferred on the senior secured trustee. The holders of a majority in principal amount of the outstanding senior secured debt securities generally will have the right to waive any past default or event of default under the senior secured indenture, except a default in the payment of principal, premium or interest on the senior secured debt securities. The senior secured indenture provides that no holder of senior secured debt securities may institute any action against us under the senior secured indenture except as described in the next paragraph or unless such holder previously shall have given to the senior secured trustee written notice of default and continuance thereof and unless the holders of not less than a majority in aggregate principal amount of senior secured debt securities shall have requested the senior secured trustee to institute such action and shall have offered the senior secured trustee reasonable indemnity, and the senior secured trustee shall not have instituted such action within 60 days of such request. Furthermore, no holder of senior secured debt securities will be entitled to institute any such action if and to the extent that such action would disturb or prejudice the rights of other holders of senior secured debt securities.

Notwithstanding the foregoing, each holder of senior secured debt securities has the right, which is absolute and unconditional, to receive payment of the principal of, premium, if any, and interest on such senior secured debt securities when due and to institute suit for the enforcement of any such payment, and such rights may not be impaired without the consent of that holder of senior secured debt securities.

The senior secured indenture provides that the senior secured trustee, within 90 days after the occurrence of a default with respect to the senior secured debt securities actually known to the senior secured trustee, is required to give the holders of the senior secured debt securities notice of such default, unless cured or waived, but, except in the case of default in the payment of principal of, premium or interest on any senior secured debt securities, the senior secured trustee may withhold such notice if it determines in good faith that it is in the interest of such holders to do so. We are required to deliver to the senior secured trustee each year a certificate as to whether or not, to the knowledge of the officer signing such certificate, we are in compliance with the conditions and covenants under the senior secured indenture.

Modification

The senior secured trustee and we may modify and amend the senior secured indenture with the consent of the holders of a majority in principal amount of the outstanding senior secured debt securities, considered as one class, provided that no such modification or amendment may, without the consent of the holder of each outstanding senior secured debt security affected thereby:

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The senior secured trustee and we may modify and amend the senior secured indenture without the consent of the holders:

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A supplemental indenture which changes or eliminates any covenant or other provision of the senior secured indenture (or any supplemental indenture) which has expressly been included solely for the benefit of one or more series of senior secured debt securities, or which modifies the rights of the holders of senior secured debt securities of such series with respect to such covenant or provision, will be deemed not to affect the rights under the senior secured indenture of the holders of senior secured debt securities of any other series.

Defeasance and Discharge

The senior secured indenture provides that we will be discharged from any and all obligations in respect of the senior secured debt securities and the senior secured indenture, except for certain obligations such as obligations to register the transfer or exchange of senior secured debt securities, replace stolen, lost or mutilated senior secured debt securities and maintain paying agencies, if, among other things, we irrevocably deposit with the senior secured trustee, in trust for the benefit of holders of senior secured debt securities, money or certain United States government obligations, or any combination thereof, which through the payment of interest thereon and principal thereof in accordance with their terms will provide money in an amount sufficient, without reinvestment, to make all payments of principal of, premium, if any, and interest on the senior secured debt securities on the dates such payments are due in accordance with the terms of the senior secured indenture and the senior secured debt securities; provided that, unless all of the senior secured debt securities are to be due within 90 days of such deposit by redemption or otherwise, we shall also have delivered to the senior secured trustee an opinion of counsel expert in federal tax matters to the effect that we have received from, or there has been published by, the Internal Revenue Service a ruling or similar pronouncement by the Internal Revenue Service or that there has been a change in law, in either case to the effect that the holders of the senior secured debt securities will not recognize income, gain or loss for federal income tax purposes as a result of such defeasance or discharge of the senior secured indenture and will be subject to federal income tax on the same amounts, in the same manner and at the same times as would have been the case absent such defeasance or discharge of the senior secured indenture. Thereafter, the holders of senior secured debt securities must look only to such deposit for payment of the principal of, premium, if any, and interest on the senior secured debt securities.

Consolidation, Merger and Sale or Disposition of Assets

We have agreed not to consolidate with or merge into any other corporation or sell or otherwise dispose of our properties substantially as an entirety to any person unless:

Upon any such consolidation, merger, sale or other disposition of our properties substantially as an entirety, the successor corporation formed by such consolidation or into which we are merged or the person to which such sale or other disposition is made shall succeed to, and be substituted for, and may exercise every right and power

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of, us under the senior secured indenture with the same effect as if such successor corporation or person had been named as us therein and we will be released from all obligations under the senior secured indenture. For purposes of the senior secured indenture, the conveyance or other transfer by us of:

in each case considered alone or in any combination with properties described in any other clause, shall in no event be deemed to constitute a conveyance or other transfer of all our properties as or substantially as an entirety.

Certain Covenants

Limitation on Liens

The senior secured indenture provides that we may not issue, assume, guarantee or permit to exist after the release date any Debt (as defined herein) that is secured by any mortgage, security interest, pledge, lien or other encumbrance (“Lien”) of or upon any of our Operating Property (as defined herein), whether owned at the date of the senior secured indenture or thereafter acquired, without in any such case effectively securing the senior secured debt securities (together with, if we shall so determine, any of our other indebtedness ranking equally with the senior secured debt securities) equally and ratably with such Debt (but only so long as such Debt is so secured).

The foregoing restriction will not apply to:

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Also, the foregoing restriction will not apply to the issuance, assumption or guarantee by us of Debt secured by a Lien that would otherwise be subject to the foregoing restrictions up to an aggregate principal amount which, together with all our other secured Debt (not including secured Debt permitted under any of the foregoing exceptions) and the Value (as defined below) of Sale and Lease-Back Transactions (as defined below) existing at such time (other than Sale and Lease-Back Transactions the proceeds of which have been applied to the retirement of certain indebtedness, Sale and Lease-Back Transactions in which the property involved would have been permitted to be mortgaged under any of the foregoing exceptions in clauses (1) to (5) and Sale and Lease-Back Transactions that are permitted by the first sentence of “—Limitation on Sale and Lease-Back Transactions”), does not exceed 15% of Capitalization (as defined herein).

Limitation on Sale and Lease-Back Transactions

The senior secured indenture provides that we may not enter into or permit to exist after the release date any Sale and Lease-Back Transaction (as defined herein) with respect to any Operating Property (except for transactions involving leases for a term, including renewals, of not more than 48 months), if the purchaser’s commitment is obtained more than 18 months after the later of (i) the completion of the acquisition and (ii) the placing in operation of such Operating Property or of such Operating Property as constructed or developed or substantially repaired, altered or improved. This restriction will not apply if:

Certain Definitions

“Capitalization” means the total of all the following items appearing on, or included in, our consolidated balance sheet:

Subject to the foregoing, Capitalization shall be determined in accordance with generally accepted accounting principles and practices applicable to the type of business in which we are engaged and that are approved by independent accountants regularly retained by us, and may be determined as of a date not more than 60 days prior to the happening of an event for which such determination is being made.

“Debt” means any of our outstanding debt for money borrowed evidenced by notes, debentures, bonds, or other securities, or guarantees of any thereof.

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“Operating Property” means:

“Sale and Lease-Back Transaction” means any arrangement with any person providing for the leasing to us of any Operating Property (except for leases for a term, including any renewals thereof, of not more than 48 months), which Operating Property has been or is to be sold or transferred by us to such person; provided, however, Sale and Lease-Back Transaction does not include any arrangement first entered into prior to the date of the senior secured indenture.

“Value” means, with respect to a Sale and Lease-Back Transaction, as of any particular time, the amount equal to the greater of:

Voting of Senior Note Mortgage Bonds Held by Senior Secured Trustee

The senior secured trustee, as the holder of the senior note mortgage bonds, will attend any meeting of bondholders under the mortgage indenture, or, at its option, will deliver its proxy in connection therewith relating to matters with respect to which it is entitled to vote or consent. So long as no event of default under the senior secured indenture shall have occurred and be continuing, the senior secured trustee shall vote all senior note mortgage bonds then held by it, or consent with respect thereto, proportionately with the vote or consent of the holders of all other first mortgage bonds outstanding under the mortgage indenture, the holders of which are eligible to vote or consent; provided, however, that the senior secured trustee shall not so vote in favor of, or so consent to, any amendment or modification of the mortgage indenture which, if it were an amendment or modification of the senior secured indenture, would require the consent of holders of senior secured debt securities as described under “—Modification,” without the prior consent of holders of senior secured debt securities that would be required for such an amendment or modification of the senior secured indenture. If there are no holders of other first mortgage bonds outstanding under the mortgage indenture who are eligible to vote or consent with respect to any amendment or modification of the mortgage indenture, the senior secured trustee shall vote the senior note mortgage bonds then held by it, or consent with respect thereto, in accordance with the consent of the holders of senior secured debt securities that would be required for such an amendment or modification of the senior secured indenture. Each initial and future holder of senior secured notes of every series issued after May 15, 2012, by its acquisition of an interest in such senior secured notes, irrevocably (a) consents to each of the amendments to the mortgage indenture described under “Description of First Mortgage Bonds and Mortgage Indenture” entitled: “—Priority and Security,” “—Issuance of Additional First Mortgage Bonds,” “—Release of Property,” “—Withdrawal of Cash,” “—Consolidation, Merger, Sale or Lease,” “—Modification of the Mortgage Indenture” and “—Mortgage Events of Default” without any other or further action by any holder of such senior secured notes, and (b) designates the senior secured trustee, and its successors, as its proxy with irrevocable instructions to vote and deliver written consents on behalf of such holder in favor of such amendments at any meeting of noteholders or bondholders, in lieu of any meeting of noteholders or bondholders, in response to any consent solicitation or otherwise.

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Resignation or Removal of Senior Secured Trustee

The senior secured trustee may resign at any time upon written notice to us specifying the day upon which the resignation is to take effect and such resignation will take effect immediately upon the later of the appointment of a successor trustee and such specified day. The senior secured trustee may be removed at any time by an instrument or concurrent instruments in writing filed with the senior secured trustee and signed by the holders, or their attorneys-in-fact, of at least a majority in principal amount of the then outstanding senior secured debt securities. In addition, so long as no event of default or event which, with the giving of notice or lapse of time or both, would become an event of default has occurred and is continuing, we may remove the senior secured trustee upon notice to the holder of each senior secured debt security outstanding and the senior secured trustee, and appointment of a successor trustee.

Concerning the Senior Secured Trustee

We and our affiliates maintain corporate trust and other banking relationships with The Bank of New York Mellon and its affiliates.

The Bank of New York Mellon is also acting as trustee under the mortgage indenture. As trustee under the senior secured indenture, The Bank of New York Mellon could have a conflicting interest for purposes of the Trust Indenture Act of 1939 if an event of default were to occur under the senior secured indenture. In that case, the senior secured trustee may be required to eliminate such conflicting interest by resigning as senior secured trustee. There are other instances under the Trust Indenture Act of 1939 which would require the resignation of the senior secured trustee if a senior secured indenture event of default were to occur, such as an affiliate of the senior secured trustee acting as underwriter with respect to any of the senior secured debt securities.

Governing Law

The senior secured indenture is, and the senior secured debt securities will be, governed by New York law.

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DESCRIPTION OF FIRST MORTGAGE BONDS AND MORTGAGE INDENTURE

General

Each series of first mortgage bonds will be a new series of first mortgage bonds issued under our Mortgage and Deed of Trust dated June 15, 1937 between us and The Bank of New York Mellon, as successor mortgage trustee, as supplemented, modified and amended by various supplemental indentures, which we collectively refer to as the “mortgage indenture.” The mortgage indenture and the form of supplemental indenture establishing the first mortgage bonds of a particular series are exhibits to, or will be subsequently incorporated by reference into, the registration statement of which this prospectus is a part. The mortgage indenture has been qualified under the Trust Indenture Act of 1939. The first mortgage bonds of all series that may be issued under the mortgage indenture are referred to under this caption as “first mortgage bonds.” The following summaries of certain provisions of the mortgage indenture do not purport to be complete and are subject to, and qualified in their entirety by, all of the provisions of the mortgage indenture and the first mortgage bonds.

The first mortgage bonds will be issued directly or as security for our obligations under the senior secured indenture and the senior secured debt securities issued thereunder. We refer to first mortgage bonds issued to secure our obligations under the senior secured indenture and the senior secured debt securities issued thereunder as “senior note mortgage bonds”.

Reserved Rights to Amend the Mortgage Indenture

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds, including any senior note mortgage bonds, issued after the date of this prospectus to amend the mortgage indenture as described under “Description of First Mortgage Bonds and Mortgage Indenture” entitled: “—Priority and Security,” “—Issuance of Additional First Mortgage Bonds,” “—Release of Property,” “—Withdrawal of Cash,” “—Consolidation, Merger, Sale or Lease,” “—Modification of the Mortgage Indenture” and “—Mortgage Events of Default.” Unless otherwise indicated in the applicable prospectus supplement, each initial and future holder of the first mortgage bonds, including the senior note mortgage bonds, issued after the date of this prospectus will, by its acquisition of an interest in the first mortgage bonds, irrevocably consent to the amendments to the mortgage indenture that we have reserved the right to make.

Priority and Security

The first mortgage bonds, including the senior note mortgage bonds, will be secured by the lien of the mortgage indenture, which, subject to certain exceptions, is a first lien on substantially all of our properties. The mortgage indenture also contains provisions subjecting property we acquire in the future (with certain exceptions) to the lien of the mortgage indenture.

The lien of the mortgage indenture on our properties may be subject to permitted liens which include tax liens and other assessments which are not delinquent or which are being contested, undetermined liens and charges incidental to construction, easements, reservations and rights of others (including governmental entities) in, and defects of title in, certain property of ours, certain liens on rights of way for transmission or distribution line purposes, and certain liens in favor of the mortgage trustee. We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to amend the definition of permitted liens to include, among other things,

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In addition, there are excepted from the lien of the mortgage indenture, among other things, the following:

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We sometimes refer to property of ours not covered by the lien of the mortgage indenture as “excepted property.” We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to exclude from the lien of the mortgage indenture, among other things, the following types of property, whether then owned or acquired in the future:

The mortgage indenture contains provisions subjecting certain after-acquired property to the lien thereof. These provisions are limited in the case of consolidation or merger (whether or not we are the surviving entity) or sale of substantially all of our assets. In the event of consolidation or merger or the sale of all or substantially all of our property as an entirety, the mortgage indenture will not be required to be a lien upon any of the properties then owned or thereafter acquired by the successor entity except properties acquired from us in or as a result of such transaction and improvements, extensions and additions to such properties and replacements and substitutions of or for any part or parts of such properties. See “—Consolidation, Merger, Sale or Lease.”

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We may acquire mortgaged property that is subject to vendors’ liens, purchase money liens and other prior liens with two limitations if such prior lien is not a permitted lien, i.e. (a) at the time of acquisition, the principal amount of outstanding indebtedness secured by such prior lien may not exceed 60% of the lesser of the cost or fair value of the property of the nature of property additions subject to such lien and (b) the net earnings of such property available for interest and property retirement appropriations for 12 consecutive calendar months during the 15 calendar months preceding such acquisition have been at least the greater of twice the amount of annual interest charges on, or 10% of the principal amount of, all outstanding indebtedness secured by such lien. In addition, so long as any first mortgage bonds issued before the date of this prospectus remain outstanding, we have agreed that the net earnings of such property available for interest after property retirement appropriations for 12 consecutive calendar months during the 15 calendar months preceding such acquisition have been at least equal to twice the annual interest on all outstanding indebtedness secured by such lien. We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to permit us to acquire mortgaged property that is subject to vendors’ liens, purchase money liens and other prior liens without the foregoing limitations but with the following limitation: if the prior lien constitutes a lien (other than a permitted lien) on any property additions owned by us immediately before such acquisition that ranks prior to or on a parity with the lien of the mortgage indenture on such property additions, the principal amount of outstanding indebtedness secured by such prior lien may not exceed the bonding ratio multiplied by the fair value of the property so acquired.

The mortgage indenture provides that the mortgage trustee will have a lien, prior to the lien on behalf of the holders of mortgage bonds, upon the mortgaged property for the payment of its reasonable compensation and certain expenses and taxes and for indemnity against certain liabilities.

Issuance of Additional First Mortgage Bonds

The maximum principal amount of first mortgage bonds which may be issued under the mortgage indenture is unlimited. First mortgage bonds of any series may be issued from time to time under the mortgage indenture on the basis of, and in an aggregate principal amount not exceeding:

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to increase the bonding ratio up to 70%.

“Bondable property” and “property additions” generally include any property which is owned by us, is subject to the lien of the mortgage indenture, is used or useful for our electric or steam business and is chargeable to our fixed property accounts, except goodwill and going concern value, separate franchises and governmental permits, gas properties, transportation properties, and certain leasehold estates, rights of way and easements. Bondable property and property additions include construction work in progress on nuclear facilities and nuclear fuel. We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to provide that bondable property and property additions generally include any property which is owned by us and is subject to the lien of the mortgage

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indenture except (with certain exceptions) goodwill and going concern value rights, and property the cost of acquisition or construction of which is properly chargeable to an operating expense account of ours.

The “net bondable value of property additions” is generally (a) the lesser of cost or fair value to us of all property additions not subject to an unfunded prior lien, subject to certain adjustments for releases and other retirements, less (b) 10/6ths of the aggregate principal amount of first mortgage bonds authenticated and delivered on the basis of property additions. We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to change the 10/6ths in the preceding sentence to the reciprocal of the bonding ratio. (For example, the reciprocal of the current bonding ratio of 60% is 10/6ths. If the bonding ratio were increased to 70%, then the reciprocal would be 10/7ths.)

“Unfunded prior liens” are liens (other than permitted liens) on the mortgaged property that are prior to the lien of the mortgage, secure obligations other than first mortgage bonds, and are not secured by a deposit of moneys sufficient to pay those obligations.

In general, the issuance of additional first mortgage bonds is also subject to:

We do not need to satisfy these earnings tests in order to issue first mortgage bonds to refund first mortgage bonds previously issued, or to refund a prior lien which simultaneously becomes a funded prior lien upon the property additions made on the basis of such application, if we make the application to issue additional first mortgage bonds for either of these two purposes at any time after a date two years prior to the maturity of the first mortgage bonds or prior lien bonds being refunded. We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to delete the test set forth under (A) above with respect to the issuance of additional Bonds.

Our “net earnings available for interest and property retirement appropriations” is defined as total operating revenues and net non-operating revenues, less operating expenses (other than income taxes). Our “net earnings available for interest after property retirement appropriations” is defined as total operating revenues and net non-operating revenues, less operating expenses (other than income taxes) and less the greater of (1) the provisions for depreciation and expenditures for maintenance and repairs for the period in question or (2) 15% of gross operating revenues (as defined) for the period in question.

Prior lien bonds secured by an unfunded prior lien may be issued under the circumstances and subject to the conditions and limitations contained in the mortgage indenture referred to above. We have no plans to issue any such bonds.

Provisions of a Particular Series

The prospectus supplement applicable to each series of first mortgage bonds, other than senior note mortgage bonds, will specify, among other things:

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Unless otherwise indicated in the applicable prospectus supplement, the first mortgage bonds will be denominated in United States currency in minimum denominations of $1,000 and integral multiples thereof.

The senior note mortgage bonds will have the same aggregate principal amount, interest rate and maturity date as the related series of senior secured debt securities and will be redeemable when the related series of senior secured debt securities is redeemable or when payment of the related series of senior secured debt securities has been accelerated after an event of default. Upon payment of the principal of, premium, if any, or interest on the senior secured debt securities, senior note mortgage bonds of the corresponding series in a principal amount equal to the principal amount of such senior secured debt securities so paid will be deemed fully paid and our obligation to make such payment shall be discharged.

Unless otherwise provided in the applicable prospectus supplement, there are no provisions in the mortgage indenture or the first mortgage bonds that require us to redeem, or permit the holders to cause a redemption of, the first mortgage bonds or, except as described under “—Priority and Security” and “—Issuance of Additional First Mortgage Bonds,” that otherwise protect the holders in the event that we incur substantial additional indebtedness, whether or not in connection with a change in control.

Registration, Transfer and Exchange

Unless otherwise indicated in the applicable prospectus supplement, other than senior note mortgage bonds, each series of first mortgage bonds will initially be issued in the form of one or more global securities, in registered form, without coupons, as described under “Book-Entry System.” The global securities will be registered in the name of a nominee of DTC, as depository, and deposited with, or on behalf of, the depository. Except as set forth under “Book-Entry System,” owners of beneficial interests in a global security will not be entitled to have first mortgage bonds registered in their names, will not receive or be entitled to receive physical delivery of any first mortgage bonds and will not be considered the registered holders thereof under the mortgage indenture.

First mortgage bonds may be exchanged for other first mortgage bonds of any authorized denominations of a like aggregate principal amount and tenor. Unless otherwise indicated in the applicable prospectus supplement, subject to the terms of the mortgage indenture, first mortgage bonds may be presented for exchange or registration of transfer—duly endorsed or accompanied by a duly executed written instrument of transfer—at the office of the transfer agent we may designate for such purpose with respect to any series of first mortgage bonds, without service charge but upon payment of any stamp taxes and other governmental charges as described in the mortgage indenture. Such transfer and exchange will be effected upon the mortgage trustee and us being satisfied with the endorsements or instruments of transfer and the identity or authorization of the person making the request. In the case of any first mortgage bonds that have been mutilated, destroyed, lost or stolen, new first mortgage bonds of a like aggregate principal amount and tenor will be issued upon the mortgage trustee and us being satisfied with the evidence of ownership and loss and with the indemnity provided.

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Notwithstanding the foregoing, we will not be required to transfer or exchange any first mortgage bonds for a period of 5 days before an interest payment date for such first mortgage bonds or the redemption date of such first mortgage bonds.

The senior note mortgage bonds will be immediately delivered to, and registered in the name of, the senior secured trustee. The senior secured indenture provides that the senior secured trustee shall not transfer any senior note mortgage bonds except to a successor trustee, to us, as provided in the senior secured indenture, or in compliance with a court order in connection with a bankruptcy or reorganization proceeding of us. The senior secured trustee shall generally vote the senior note mortgage bonds proportionately with what it believes to be the vote of all other first mortgage bonds then outstanding, as described under “Description of Senior Secured Debt Securities—Voting of Senior Note Mortgage Bonds Held by Senior Secured Trustee.”

Payment and Paying Agents

Payments with respect to principal of, premium, if any, and interest on first mortgage bonds, issued in the form of global securities will be paid in the manner described below under “Book-Entry System.”

Unless otherwise indicated in the applicable prospectus supplement, interest on first mortgage bonds, other than interest at maturity, that are in the form of certificated securities will be paid by check payable in clearinghouse funds mailed to the person entitled thereto at such person’s address as it appears in the register for the first mortgage bonds; provided, however, a holder of first mortgage bonds of one or more series under the mortgage indenture in the aggregate principal amount of $10,000,000 or more having the same interest payment dates will be entitled to receive payments of interest on such series by wire transfer of immediately available funds to a bank within the continental United States if the mortgage trustee has received appropriate wire transfer instructions on or prior to the applicable regular record date for such interest payment date. Unless otherwise indicated in the applicable prospectus supplement, the principal of, premium, if any, and interest at maturity on, first mortgage bonds in the form of certificated securities will be payable in immediately available funds at the office of the mortgage trustee or at the authorized office of any paying agent upon presentation and surrender of such first mortgage bonds. We may appoint additional paying agents from time to time, including ourselves or our affiliates.

All monies we pay to the mortgage trustee for the payment of principal of, premium, if any, and interest on any first mortgage bonds which remain unclaimed at the end of six years after such principal, premium or interest shall have become due and payable will be repaid to us, subject to applicable abandoned property laws, and the holder of such first mortgage bonds thereafter may look only to us for payment thereof.

In any case where the date on which the principal of, premium, if any, or interest on any first mortgage bond is due or the date fixed for redemption of any first mortgage bond is not a business day (as defined in the mortgage indenture), then payment of that principal, premium or interest need not be made on such date but may be made on the next succeeding business day with the same force and effect as if made on the due date or the date fixed for redemption, and, in the case of timely payment on such business day, no additional interest shall accrue for the period from and after such principal, premium or interest is stated to be due to such business day.

Redemption Provisions

The senior note mortgage bonds will be redeemed on the respective dates and in the respective principal amounts that correspond to the redemption dates for, and the principal amounts to be redeemed of, the corresponding series of senior secured debt securities. The senior note mortgage bonds will not be entitled to any covenant providing for the retirement or amortization of senior note mortgage bonds outstanding or for the certification of expenditures for bondable property in lieu of such retirement.

In the event of an event of default under the senior secured indenture and acceleration of the senior secured debt securities, the senior note mortgage bonds will be immediately redeemable in whole, upon demand of the

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senior secured trustee, and surrender thereof to the mortgage trustee, at a redemption price of 100% of the principal amount thereof, together with accrued interest to the redemption date.

With respect to any first mortgage bonds that are not senior note mortgage bonds, any terms for the optional or mandatory redemption of such first mortgage bonds will be indicated in the applicable prospectus supplement. Unless otherwise indicated in the applicable prospectus supplement, such first mortgage bonds will be redeemable only upon notice by mail not less than 30 nor more than 60 days prior to the date fixed for redemption, and, if less than all the first mortgage bonds of a series are to be redeemed, the particular first mortgage bonds to be redeemed will be selected by the mortgage trustee in such manner as it shall deem appropriate and fair. Any notice of redemption at our option may state that such redemption will be conditional upon receipt by the mortgage trustee, on or prior to the date fixed for such redemption, of money sufficient to pay the principal of, premium, if any, and interest on such first mortgage bonds and that if such money has not been so received, such notice will be of no force and effect and we will not be required to redeem such first mortgage bonds.

Mortgage Events of Default

Each of the following events constitutes an event of default under the mortgage indenture, referred to in this prospectus as a “mortgage event of default”:

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to delete the defaults described in the last two bullets above.

Remedies

If a mortgage event of default occurs and is continuing, then the mortgage trustee or the holders of not less than 25% in principal amount of the first mortgage bonds then outstanding may declare the principal amount of all of the first mortgage bonds to be immediately due and payable. At any time after such declaration, but before the sale of any of the mortgaged property, the holders of a majority of outstanding first mortgage bonds may rescind such declaration if all defaults (other than the payment of principal which has been so declared due and payable) have been cured. The mortgage trustee is required to enforce the lien of the mortgage indenture upon request of the holders of a majority in amount of the outstanding first mortgage bonds on default. The mortgage trustee has no obligations to exercise any of its trusts or powers at the request of any of the bondholders unless indemnified to its satisfaction, but the mortgage trustee is not relieved of its obligation to act upon the occurrence of a mortgage event of default.

The mortgage indenture provides that, under certain circumstances and to the extent permitted by law, if a mortgage event of default occurs and is continuing, the mortgage trustee has the power to take possession of, and

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to hold, operate and manage, the mortgaged property, or with or without entry, to sell the mortgaged property. If the mortgaged property is sold, whether by the mortgage trustee or pursuant to judicial proceedings, the principal of the outstanding mortgage bonds, if not previously due, will become immediately due, together with any accrued interest.

The holders of a majority in principal amount of the first mortgage bonds then outstanding will have the right to direct the time, method and place of conducting any proceedings for any remedy available to the mortgage trustee or exercising any trust or power conferred on the mortgage trustee, provided that:

The mortgage indenture provides that no holder of any first mortgage bond will have any right to institute any proceeding, judicial or otherwise, with respect to the mortgage indenture or the appointment of a receiver or trustee, or for any other remedy thereunder except as described in the next paragraph or unless, at the option of the mortgage trustee:

Furthermore, no holder will be entitled to institute any such action if and to the extent that such action would affect, disturb or prejudice the lien of the mortgage indenture or would not be for the ratable benefit of all holders.

Notwithstanding the foregoing, each holder of a first mortgage bond has the right, which is absolute and unconditional, to receive payment of the principal of, premium, if any, and interest on such first mortgage bond when due and to institute suit for the enforcement of any such payment, and such rights may not be impaired without the consent of such holder.

The mortgage indenture provides that the mortgage trustee must give the holders notice of any mortgage event of default (not including the periods of grace provided in the second and fourth bullet points under “—Mortgage Events of Default”) under the mortgage indenture within 90 days after the occurrence thereof, unless such mortgage event of default shall have been cured, except that no such notice to holders of a mortgage event of default of the character described in the fourth bullet point under “—Mortgage Events of Default” may be given until at least 60 days after the occurrence thereof. The mortgage indenture and Trust Indenture Act of 1939 currently permits the mortgage trustee to withhold notices of default (except for notices of certain payment defaults) if the mortgage trustee in good faith determines the withholding of such notice to be in the interest of the holders. We are required to deliver to the mortgage trustee each year a certificate as to whether or not, to the knowledge of the officer signing such certificate, we are in compliance with the conditions and covenants under the mortgage indenture.

As a condition precedent to certain actions by the mortgage trustee at the request or direction of bondholders, the mortgage trustee may require indemnity reasonably satisfactory to it against costs, expenses and liabilities to be incurred in connection therewith.

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Modification of the Mortgage Indenture

Without the consent of any holders of the first mortgage bonds, we and the mortgage trustee may enter into one or more supplemental indentures for any of the following purposes:

Except as provided above, the consent of the holders of 60% of the principal amount of first mortgage bonds, and 60% in principal amount of first mortgage bonds of each affected series if less than all are affected, is required for the purpose of modifying or altering any of the provisions of, the mortgage indenture pursuant to one or more supplemental indentures.

Furthermore, no such amendment or modification of the mortgage indenture may, without the consent of each holder of the outstanding first mortgage bonds affected thereby:

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to provide that, without the consent of any holders of the mortgage bonds, we and the mortgage trustee may enter into one or more supplemental indentures for any of the following purposes:

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We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to provide that, without limiting the generality of the foregoing, if the Trust Indenture Act of 1939 is amended after the date of this prospectus in such a way as to require changes to the mortgage indenture or the incorporation therein of additional provisions or so as to permit changes to, or the elimination of, provisions which, at the date of the mortgage indenture or at any time thereafter, were required by the Trust Indenture Act of 1939 to be contained in the mortgage indenture, we and the mortgage trustee may, without the consent of any holders of first mortgage bonds, enter into one or more supplemental indentures to evidence or effect such amendment.

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to provide that, except as provided above, the consent of the holders of a majority in aggregate principal amount of the mortgage bonds of all series then outstanding, considered as one class, is required for the purpose of adding any provisions to, or changing in any manner, or eliminating any of the provisions of, the mortgage indenture or waiving any default, mortgage event of default or other rights of the bondholders or the mortgage trustee pursuant to one or more supplemental indentures or instruments. However, if less than all of the series of first mortgage bonds outstanding are directly affected by a proposed supplemental indenture or instrument, then the consent only of the holders of a majority in aggregate principal amount of outstanding mortgage bonds of all series so directly affected, considered as one

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class, will be required. However, no such waiver, amendment or modification of the mortgage indenture may, without the consent of the holder of each outstanding first mortgage bond directly affected thereby:

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to provide that a supplemental indenture which waives, changes or eliminates any covenant or other provision of the mortgage indenture which has expressly been included solely for the benefit of the holders of, or which is to remain in effect only so long as there shall be outstanding first mortgage bonds of one or more specified series, or waives or modifies the rights of the holders of first mortgage bonds of such series with respect to such covenant or other provision, will be deemed not to affect the rights under the mortgage indenture of the holders of the first mortgage bonds of any other series.

Waiver

The holders of 60% in aggregate principal amount of all first mortgage bonds, and, and 60% in principal amount of first mortgage bonds of each affected series if less than all are affected, may consent to any modifications or alterations to the rights of bondholders that may be effected at a meeting of bondholders with the vote of the holders of the same percentage in aggregate principal amount of first mortgage bonds.

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to provide that the consent of the holders of a majority in aggregate principal amount of the mortgage bonds of all series then outstanding, considered as one class, may waive any default, mortgage event of default or any of our covenants. However, if less than all of the series of first mortgage bonds outstanding are directly affected by a proposed waiver, then the holders of a majority in aggregate principal amount of all first mortgage bonds directly affected, considered as one class, may waive any default, mortgage event of default or any of our covenants, provided that no such waiver may, without the consent of the holder of each outstanding first mortgage bond directly affected thereby:

Defeasance and Discharge

Upon the payment of, or the deposit of money with the mortgage trustee sufficient to pay, the principal of, premium, if any, and interest, if any, when due on all outstanding first mortgage bonds to the maturity date or a specified redemption date of those bonds, the mortgage indenture will cease to be in effect and we may require the mortgage trustee to discharge the lien of the mortgage indenture.

Consolidation, Merger, Sale or Lease

We have agreed not to merge or consolidate into or with any other corporation, voluntary association, joint stock company or business trust or sell or lease all or substantially all of our property as an entirety (including a sale in connection with our liquidation) to any such entity unless:

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In the case of a consolidation, merger, or a sale of all or substantially all of our property as an entirety to any other entity, upon the satisfaction of all the conditions described above and the recording of the supplemental indenture, the successor entity would succeed to and be substituted for us under the mortgage indenture.

Although the successor entity may, in its sole discretion, subject to the lien of the mortgage indenture property then owned or thereafter acquired by the successor entity, the lien of the mortgage indenture generally will not cover the property of the successor entity other than the mortgaged property it acquires from us and improvements, extensions and additions to such mortgaged property and replacements and substitutions thereof, within the meaning of the mortgage indenture.

We have reserved the right to amend the mortgage indenture without any consent or other action of the holders of any first mortgage bonds issued after the date of this prospectus to restate the provisions described above under “—Consolidation, Merger, Sale or Lease” to provide the following:

We have agreed not to consolidate with or merge into any other entity or convey, transfer or lease the mortgaged property as or substantially as an entirety to any entity unless:

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In the case of the conveyance or other transfer of the mortgaged property as or substantially as an entirety to any other entity, upon the satisfaction of all the conditions described above, we would be released and discharged from all our obligations and covenants under the mortgage indenture and on the mortgage bonds then outstanding unless we elect to waive such release and discharge.

As so amended, the mortgage indenture will not prevent or restrict:

As so amended, the successor entity may, in its sole discretion, subject to the lien of the mortgage indenture any property then owned or thereafter acquired by the successor entity, but the lien of the mortgage indenture generally will not cover the property of the successor entity other than (i) the mortgaged property owned by us immediately prior to such transaction that is allocated or transferred to the successor entity in or as a result of such transaction and (ii) improvements, extensions and additions to such mortgaged property and renewals, replacements and substitutions thereof, within the meaning of the mortgage indenture.

DESCRIPTION OF SENIOR UNSECURED DEBT SECURITIES

General

The senior unsecured debt securities will represent our unsecured obligations. We may issue one or more series of senior unsecured debt securities directly to the public from time to time. We will issue the senior unsecured debt securities in one or more series under a senior unsecured indenture between us and a trustee. The form of the senior unsecured indenture or other instrument establishing the senior unsecured debt securities of a particular series are exhibits to, or will be subsequently incorporated by reference into, the registration statement of which this prospectus is a part. The senior unsecured indenture will be qualified under the Trust Indenture Act of 1939. The senior unsecured debt securities of all series that may be issued under the senior unsecured indenture are referred to under this caption as “senior unsecured debt securities.” The following summaries of certain provisions of the senior unsecured indenture do not purport to be complete and are subject to, and qualified in their entirety by, all provisions of the senior unsecured indenture and the senior unsecured debt securities.

Ranking

The senior unsecured debt securities will be our direct unsecured general obligations and will rank equally with all of our other unsecured and unsubordinated debt and will be effectively junior to all of our secured debt, including our first mortgage bonds (and the related senior secured debt securities), as to the collateral pledged to secure this debt. Unless otherwise indicated in a subsequent prospectus supplement, the senior unsecured indenture will not limit the aggregate amount of debt we may incur.

The senior unsecured indenture provides that our obligations to compensate the trustee and reimburse the trustee for expenses, disbursements and advances will constitute indebtedness which will be secured by a lien generally prior to that of the senior unsecured debt securities upon all property and funds held or collected by the trustee as such.

Issuance of Additional Senior Unsecured Debt Securities

The senior unsecured indenture will provide that additional senior unsecured debt securities may be issued thereunder without limitation as to aggregate principal amount.

Provisions of a Particular Series

The prospectus supplement applicable to each series of senior unsecured debt securities will specify:

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Unless otherwise indicated in the applicable prospectus supplement, the senior unsecured debt securities will be denominated in United States currency in minimum denominations of $1,000 and integral multiples thereof.

There will be no requirement under the senior unsecured indenture that our future issuances of debt securities be issued exclusively under the senior unsecured indenture, and we will be free to employ other indentures or documentation, containing provisions different from those included in the senior unsecured indenture or applicable to one or more issuances of senior unsecured debt securities, in connection with future issuances of other debt securities, including as described in this prospectus under “Description of Senior Secured Debt Securities.”

The senior unsecured indenture will provide that the senior unsecured debt securities will be issued in one or more series, may be issued at various times, may have differing maturity dates, may have differing redemption provisions and may bear interest at differing rates. We need not issue all senior unsecured debt securities of one series at the same time, and, unless otherwise provided in the applicable prospectus supplement, we may reopen a series, without the consent of the holders of the senior unsecured debt securities of that series, for issuances of additional senior unsecured debt securities of that series.

Unless otherwise provided in the applicable prospectus supplement, there will be no provisions in the senior unsecured indenture or the senior unsecured debt securities that require us to redeem, or permit the holders to cause a redemption of, the senior unsecured debt securities or that otherwise protect the holders in the event that we incur substantial additional indebtedness, whether or not in connection with a change in control.

Registration, Transfer and Exchange

Unless otherwise indicated in the applicable prospectus supplement, each series of senior unsecured debt securities will initially be issued in the form of one or more global securities, in registered form, without coupons, as described under “Book-Entry System.” The global securities will be registered in the name of a nominee of DTC, and deposited with, or on behalf of, the depository. Except as set forth under “Book-Entry System,” owners of beneficial interests in a global security will not be entitled to have senior unsecured debt securities registered in their names, will not receive or be entitled to receive physical delivery of any senior unsecured debt securities and will not be considered the registered holders thereof under the senior unsecured indenture.

Senior unsecured debt securities of any series will be exchangeable for other senior unsecured debt securities of the same series of any authorized denominations and of a like aggregate principal amount and tenor.

Unless otherwise indicated in the applicable prospectus supplement, senior unsecured debt securities may be presented for exchange or registration of transfer—duly endorsed or accompanied by a duly executed written instrument of transfer—at the office of the senior unsecured trustee maintained for such purpose with respect to any series of senior unsecured debt securities, without service charge but upon payment of any taxes and other governmental charges as described in the senior unsecured indenture. Such transfer or exchange will be effected upon the senior unsecured trustee and us being satisfied with the endorsements or instruments of transfer and the identity or authorization of the person making the request. In the case of any senior unsecured debt securities that have been mutilated, destroyed, lost or stolen, new senior unsecured debt securities of a like aggregate principal amount and tenor will be issued upon the senior unsecured trustee and us being satisfied with the evidence of ownership and loss and with the security or indemnity provided.

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In the event of any redemption of senior unsecured debt securities of any series, the senior unsecured trustee will not be required to exchange or register a transfer of any senior unsecured debt securities of such series selected, called or being called for redemption except, in the case of any senior unsecured debt security to be redeemed in part, the portion thereof not to be so redeemed.

Payment and Paying Agents

Payments with respect to principal of, premium, if any, and interest on senior unsecured debt securities issued in the form of global securities will be paid in the manner described below under “Book-Entry System.”

Unless otherwise indicated in the applicable prospectus supplement, interest on senior unsecured debt securities, other than interest at maturity, that are in the form of certificated securities will be paid by check payable in clearinghouse funds mailed to the person entitled thereto at such person’s address as it appears in the register for the senior unsecured debt securities maintained by the senior unsecured trustee; provided, however, a holder of senior unsecured debt securities of one or more series under the senior unsecured indenture in the aggregate principal amount of $10,000,000 or more having the same interest payment dates will be entitled to receive payments of interest on such series by wire transfer of immediately available funds to a bank within the continental United States if the senior unsecured trustee has received appropriate wire transfer instructions on or prior to the applicable regular record date for such interest payment date. Unless otherwise indicated in the applicable prospectus supplement, the principal of, premium, if any, and interest at maturity on, senior unsecured debt securities in the form of certificated securities will be payable in immediately available funds at the office of the senior unsecured trustee or at the authorized office of any paying agent upon presentation and surrender of such senior unsecured debt securities. We may appoint additional paying agents from time to time, including ourselves or our affiliates.

All monies we pay to the senior unsecured trustee for the payment of principal of, premium, if any, and interest on any senior unsecured debt security which remain unclaimed at the end of two years after such principal, premium or interest shall have become due and payable will be repaid to us, subject to applicable abandoned property laws, and the holder of such senior unsecured debt security thereafter may look only to us for payment thereof.

In any case where the date on which the principal of, premium, if any, or interest on any senior unsecured debt security is due or the date fixed for redemption of any senior unsecured debt security is not a business day (as defined in the senior unsecured indenture), then payment of that principal, premium or interest need not be made on such date but may be made on the next succeeding business day with the same force and effect as if made on the due date or the date fixed for redemption, and, in the case of timely payment on such business day, no additional interest shall accrue for the period from and after such principal, premium or interest is stated to be due to such business day.

Redemption Provisions

Any terms for the optional or mandatory redemption of the senior unsecured debt securities will be indicated in the applicable prospectus supplement. Unless otherwise indicated in the applicable prospectus supplement, the senior unsecured debt securities will be redeemable only upon notice by mail not less than 30 nor more than 60 days prior to the date fixed for redemption, and, if less than all the senior unsecured debt securities of a series are to be redeemed, the particular senior unsecured debt securities to be redeemed will be selected by the senior unsecured trustee in such manner as it shall deem appropriate and fair.

Any notice of redemption at our option may state that such redemption will be conditional upon receipt by the senior unsecured trustee, on or prior to the date fixed for such redemption, of money sufficient to pay the principal of, premium, if any, and interest on such senior unsecured debt securities and that if such money has not been so received, such notice will be of no force and effect and we will not be required to redeem such senior unsecured debt securities.

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Events of Default

The following constitute events of default under the senior unsecured indenture with respect to the senior unsecured debt securities:

If an event of default under the senior unsecured indenture occurs and is continuing, either the senior unsecured trustee or the holders of not less than 33% in aggregate principal amount of the outstanding senior unsecured debt securities may declare, by notice in writing, the principal amount of and interest on all senior unsecured debt securities to be due and payable immediately. At any time after an acceleration of the senior unsecured debt securities has been declared, but before a judgment or decree for the payment of the principal amount of the senior unsecured debt securities has been obtained, if we pay or deposit with the senior unsecured trustee a sum sufficient to pay all matured installments of interest and the principal and premium, if any, which has become due otherwise than by acceleration and any amounts due to the senior unsecured trustee, and all defaults shall have been cured or waived, then such payment or deposit will cause an automatic rescission and annulment of the acceleration of the senior unsecured debt securities.

The senior unsecured indenture provides that the senior unsecured trustee generally will be under no obligation to exercise any of its rights or powers under the senior unsecured indenture at the request or direction of any of the holders of senior unsecured debt securities unless such holders have offered to the senior unsecured trustee reasonable security or indemnity. Subject to such provisions for indemnity and certain other limitations contained in the senior unsecured indenture, the holders of a majority in principal amount of the outstanding senior unsecured debt securities generally will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the senior unsecured trustee, or of exercising any trust or power conferred on the senior unsecured trustee. The holders of a majority in principal amount of the outstanding senior unsecured debt securities generally will have the right to waive any past default or event of default under the senior unsecured indenture, except a default in the payment of principal, premium or interest on the senior unsecured debt securities. The senior unsecured indenture provides that no holder of senior unsecured debt securities may institute any action against us under the senior unsecured indenture except as described in the next paragraph or unless such holder previously shall have given to the senior unsecured trustee written notice of default and continuance thereof and unless the holders of not less than a majority in aggregate principal amount of senior unsecured debt securities shall have requested the senior unsecured trustee to institute such action and shall have offered the senior unsecured trustee reasonable indemnity, and the senior unsecured trustee shall not have instituted such action within 60 days of such request. Furthermore, no holder of senior unsecured debt securities will be entitled to institute any such action if and to the extent that such action would disturb or prejudice the rights of other holders of senior unsecured debt securities.

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Notwithstanding the foregoing, each holder of senior unsecured debt securities has the right, which is absolute and unconditional, to receive payment of the principal of, premium, if any, and interest on such senior unsecured debt securities when due and to institute suit for the enforcement of any such payment, and such rights may not be impaired without the consent of that holder of senior unsecured debt securities.

The senior unsecured indenture provides that the senior unsecured trustee, within 90 days after the occurrence of a default with respect to the senior unsecured debt securities actually known to the senior unsecured trustee, is required to give the holders of the senior unsecured debt securities notice of such default, unless cured or waived, but, except in the case of default in the payment of principal of, premium or interest on any senior unsecured debt securities, the senior unsecured trustee may withhold such notice if it determines in good faith that it is in the interest of such holders to do so. We are required to deliver to the senior unsecured trustee each year a certificate as to whether or not, to the knowledge of the officer signing such certificate, we are in compliance with the conditions and covenants under the senior unsecured indenture.

Modification

The senior unsecured trustee and we may modify and amend the senior unsecured indenture with the consent of the holders of a majority in principal amount of the outstanding senior unsecured debt securities, considered as one class, provided that no such modification or amendment may, without the consent of the holder of each outstanding senior unsecured debt security affected thereby:

The senior unsecured trustee and we may modify and amend the senior unsecured indenture without the consent of the holders:

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A supplemental indenture which changes or eliminates any covenant or other provision of the senior unsecured indenture (or any supplemental indenture) which has expressly been included solely for the benefit of one or more series of senior unsecured debt securities, or which modifies the rights of the holders of senior unsecured debt securities of such series with respect to such covenant or provision, will be deemed not to affect the rights under the senior unsecured indenture of the holders of senior unsecured debt securities of any other series.

Defeasance and Discharge

The senior unsecured indenture will provide that we will be discharged from any and all obligations in respect of the senior unsecured debt securities and the senior unsecured indenture, except for certain obligations such as obligations to register the transfer or exchange of senior unsecured debt securities, replace stolen, lost or mutilated senior unsecured debt securities and maintain paying agencies, if, among other things, we irrevocably deposit with the senior unsecured trustee, in trust for the benefit of holders of senior unsecured debt securities, money or certain United States government obligations, or any combination thereof, which through the payment of interest thereon and principal thereof in accordance with their terms will provide money in an amount sufficient, without reinvestment, to make all payments of principal of, premium, if any, and interest on the senior unsecured debt securities on the dates such payments are due in accordance with the terms of the senior unsecured indenture and the senior unsecured debt securities; provided that, unless all of the senior unsecured debt securities are to be due within 90 days of such deposit by redemption or otherwise, we shall also have delivered to the senior unsecured trustee an opinion of counsel expert in federal tax matters to the effect that we have received from, or there has been published by, the Internal Revenue Service a ruling or similar pronouncement by the Internal Revenue Service or that there has been a change in law, in either case to the effect that the holders of the senior unsecured debt securities will not recognize income, gain or loss for federal income tax purposes as a result of such defeasance or discharge of the senior unsecured indenture and will be subject to federal income tax on the same amounts, in the same manner and at the same times as would have been the case absent such defeasance or discharge of the senior unsecured indenture. Thereafter, the holders of senior unsecured debt securities must look only to such deposit for payment of the principal of, premium, if any, and interest on the senior unsecured debt securities.

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Consolidation, Merger and Sale or Disposition of Assets

We have agreed not to consolidate with or merge into any other corporation or sell or otherwise dispose of our properties substantially as an entirety to any person unless:

Upon any such consolidation, merger, sale, transfer or other disposition of our properties substantially as an entirety, the successor corporation formed by such consolidation or into which we are merged or the person to which such sale or other disposition is made shall succeed to, and be substituted for, and may exercise every right and power of, us under the senior unsecured indenture with the same effect as if such successor corporation or person had been named as us therein and we will be released from all obligations under the senior unsecured indenture. For purposes of the senior unsecured indenture, the conveyance or other transfer by us of:

in each case considered alone or in any combination with properties described in any other clause, shall in no event be deemed to constitute a conveyance or other transfer of all our properties, as or substantially as an entirety.

Resignation or Removal of Senior Unsecured Trustee

The senior unsecured trustee may resign at any time upon written notice to us specifying the day upon which the resignation is to take effect and such resignation will take effect immediately upon the later of the appointment of a successor trustee and such specified day. The senior unsecured trustee may be removed at any time by an instrument or concurrent instruments in writing filed with the senior unsecured trustee and signed by the holders, or their attorneys-in-fact, of at least a majority in principal amount of the then outstanding senior unsecured debt securities. In addition, so long as no event of default or event which, with the giving of notice or lapse of time or both, would become an event of default has occurred and is continuing, we may remove the senior unsecured trustee upon notice to the holder of each senior unsecured debt security outstanding and the senior unsecured trustee, and appointment of a successor trustee.

Governing Law

The senior unsecured indenture is, and the senior unsecured debt securities will be, governed by New York law.

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DESCRIPTION OF PREFERRED STOCK

General

The following statements describing preferred stock of Ameren Missouri are not intended to be a complete description but rather are a summary of certain preferences, privileges, restrictions and distinguishing characteristics relating to the preferred stock currently authorized by our Restated Articles of Incorporation (“articles of incorporation”). For additional information, please see our articles of incorporation and bylaws. Each of these documents has been previously filed with the SEC and each is an exhibit to the registration statement filed with the SEC of which this prospectus is a part. Reference is also made to the laws of the state of Missouri. The other terms and provisions of each series of preferred stock (as defined below) will be set forth in the resolution adopted by our board of directors establishing such series of preferred stock and will be described in the prospectus supplement relating to such offering.

Our authorized preferred stock consists of 25,000,000 shares of preferred stock without par value, issuable in series. When used in this prospectus, the term “preferred stock,” unless the context indicates otherwise, means all the authorized shares of our preferred stock, whether currently outstanding or hereafter issued.

The following terms and other information with respect to any series of preferred stock will be contained in a prospectus supplement:

Issuance in Series; Rank

The authorized but unissued shares of preferred stock may be issued in one or more series from time to time upon such terms and in such manner, with such variations as to dividend rates, the cumulative dates, the prices at which shares may be redeemed, the liquidation prices, the prices at which, and the terms upon which, shares may be converted into or exchanged for shares of any other class, sinking fund or purchase fund provisions, if any, and any other characteristics or restrictive or other provisions as may be determined by our board of directors. Except for such characteristics, as to which our board of directors has discretion, all series of the preferred stock rank equally and are alike in all respects. Our articles of incorporation provide that the redemption price and the liquidation price of our preferred stock shall not exceed $120 per share and the annual dividend rate shall not exceed $8 per share.

Our preferred stock ranks senior with respect to dividends and assets to our $1 par value preference stock (“preference stock”), if any, and our $5 par value common stock (“common stock”).

Dividend Rights

Holders of preferred stock are entitled to receive in respect of each share held, from the cumulative date applicable thereto, cumulative dividends at the rate applicable thereto, and no more, in preference to our common stock and to our preference stock, if any, payable quarterly on the fifteenth of February, May, August, and November in each year, when and as declared by our board of directors out of any funds legally available for such purpose.

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Unless otherwise specified in the accompanying prospectus supplement, dividends and distributions on our common stock may be declared and paid, provided all dividends for past periods and the dividend for the current quarter on our outstanding preferred stock and preference stock have been paid or provided for.

Optional Redemption Provisions

Subject to restrictions, if any, on redemptions set forth in the applicable prospectus supplement, shares of preferred stock will be redeemable, at our option, in whole at any time or in part from time to time, on not less than 30 days’ and not more than 60 days’ notice at the prices indicated in the applicable prospectus supplement. Redemption notices will be published in a daily newspaper printed in the English language and published and of general circulation in Manhattan, New York, and in a similar newspaper published and of general circulation in St. Louis, Missouri. Redemption notices will also be mailed to holders of record at their addresses appearing on our books, but failure to mail redemption notices will not affect the validity of any redemption.

Voting Rights

Each share of preferred stock, common stock and preference stock, if any, is entitled to one vote on each matter voted on at all meetings of shareholders, with the right of cumulative voting in the election of directors and the right to vote as a class on certain questions. Whenever four quarterly dividends on the preferred stock shall be in default, in whole or in part, and during the continuance of such default, the common stock, as a class, will be entitled to elect the same number of directors as was authorized by our articles of incorporation immediately prior to such default, and the preferred stock, as a class, will be entitled to elect two additional directors; and provided further, that whenever four quarterly dividends on the preference stock shall be in default, in whole or in part, and during the continuance of such default, the common stock and the preferred stock, voting together as a single class, will be entitled to elect the same number of directors as was authorized by our articles of incorporation immediately prior to such default, and the preference stock, as a class, will be entitled to elect two additional directors. The articles of incorporation give holders of the preferred stock certain special voting rights with respect to specified corporate actions, including certain amendments to the articles of incorporation, the issuance of preferred stock ranking senior to, or equally with, existing preferred shares, and certain distributions to holders of junior stock. See “—Restrictions on Certain Corporate Actions” below.

In addition, under Missouri law holders of the preferred stock have the right to vote as a class on any amendment to our articles of incorporation that would adversely affect such stock’s preferences or special or relative rights, but if less than all series of a class are adversely affected, then the affected series have the right to vote as a class on such amendment.

Liquidation Rights

In the event of any liquidation, dissolution or winding up (voluntary or involuntary) of Ameren Missouri, holders of preferred stock are entitled to receive an amount equal to the aggregate applicable liquidation price of their shares and any unpaid accrued dividends thereon, before any payment or distribution is made to the holder of our common stock and our preference stock, if any.

Common Stock of Ameren Missouri

Our board of directors may not declare or pay dividends or distributions on our common stock unless all accrued and unpaid dividends on all series of preferred stock have been paid or declared.

Restrictions on Certain Corporate Actions

The articles of incorporation provide that no amendment to the articles of incorporation:

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We may not, without the consent of the holders of at least two-thirds of the preferred stock:

Preemptive Rights

Holders of the preferred stock have no preemptive rights to subscribe for or purchase any securities issued by us.

Miscellaneous

The preferred stock have no conversion rights. There is no restriction on the repurchase or redemption by us of our common stock or preferred stock while there is any arrearage in the payment of dividends or sinking fund installments in respect of our preferred stock, except in circumstances when the repurchase or redemption of our common stock or preferred stock is otherwise prohibited or restricted by statute or common law or, as summarized with respect to distributions in “—Restrictions on Certain Corporate Actions” above, by the articles of incorporation. There is a restriction on the redemption by us of our preference stock, if any, while there is any arrearage in the payment of dividends or sinking fund installments in respect of our preferred stock or preference stock.

We reserve the right to increase, decrease or reclassify our authorized stock of any class or series thereof, and to amend or repeal any provision in the articles of incorporation or any amendment thereto, in the manner prescribed by law, subject to the conditions and limitations prescribed in the articles of incorporation; and all rights conferred on shareholders in the articles of incorporation are subject to this reservation.

Shares of preferred stock, when issued by us upon receipt of the consideration therefor, will be fully paid and non-assessable.

Transfer Agent and Registrar

Ameren Services Company serves as transfer agent and registrar for our preferred stock.

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BOOK-ENTRY SYSTEM

Unless otherwise indicated in the applicable prospectus supplement, the securities will initially be issued in the form of one or more global securities, in registered form, without coupons. The global security will be deposited with, or on behalf of, the depository, and registered in the name of the depository or a nominee of the depository. Unless otherwise indicated in the applicable prospectus supplement, the depository for any global securities will be DTC. Global debt securities registered in the name of Cede & Co. may be held by the applicable trustee as custodian for DTC.

So long as the depository, or its nominee, is the registered owner of a global security, such depository or such nominee, as the case may be, will be considered the owner of such global security for all purposes under the applicable indenture, including for any notices and voting. Except in limited circumstances, the owners of beneficial interests in a global security will not be entitled to have securities registered in their names, will not receive or be entitled to receive physical delivery of any such securities and will not be considered the registered holder thereof under the applicable indenture. Accordingly, each person holding a beneficial interest in a global security must rely on the procedures of the depository and, if such person is not a direct participant, on procedures of the direct participant through which such person holds its interest, to exercise any of the rights of a registered owner of such security.

Global securities may be exchanged in whole for certificated securities only if:

In any such case, we have agreed to notify the applicable trustee or agent in writing that, upon surrender by the direct participants and indirect participants of their interest in such global securities, certificated securities representing the applicable securities will be issued to each person that such direct participants and indirect participants and the depository identify as being the beneficial owner of such securities.

The following is based solely on information furnished by DTC:

DTC is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code, and a “clearing agency” registered pursuant to the provisions of Section 17A of the Securities Exchange Act of 1934. DTC holds and provides asset servicing for U.S. and non-U.S. equity issues, corporate and municipal debt issues and money market instruments that DTC’s participants (“Direct Participants”) deposit with DTC. DTC also facilitates the post-trade settlement among Direct Participants of sales and other securities transactions in deposited securities, through electronic computerized book-entry transfers and pledges between Direct Participants’ accounts. This eliminates the need for physical movement of securities certificates. Direct Participants include both U.S. and non-U.S. securities brokers and dealers, banks, trust companies, clearing corporations, and certain other organizations. DTC is a wholly owned subsidiary of The Depository Trust & Clearing Corporation (“DTCC”). DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others such as both U.S. and non-U.S. securities brokers and dealers, banks, trust companies, and clearing corporations that clear through or maintain a custodial relationship with a Direct Participant, either directly or indirectly (“Indirect Participants”). The DTC Rules applicable to its Participants are on file with the SEC.

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Purchases of global securities under the DTC system must be made by or through Direct Participants, which will receive a credit for the global securities on DTC’s records. The ownership interest of each actual purchaser of each security (“Beneficial Owner”) is in turn to be recorded on the Direct and Indirect Participants’ records. Beneficial Owners will not receive written confirmation from DTC of their purchase, but Beneficial Owners are expected to receive written confirmations providing details of the transaction, as well as periodic statements of their holdings, from the Direct or Indirect Participant through which the Beneficial Owner entered into the transaction. Transfers of ownership interests in the securities are to be accomplished by entries made on the books of Direct and Indirect Participants acting on behalf of Beneficial Owners. Beneficial Owners will not receive certificates representing their ownership interests in the global securities except in the event that use of the book-entry system for the global securities is discontinued.

To facilitate subsequent transfers, all global securities deposited by Direct Participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co. or such other name as may be requested by an authorized representative of DTC. The deposit of global securities with DTC and their registration in the name of Cede & Co. or such other nominee will effect no change in beneficial ownership. DTC will have no knowledge of the actual Beneficial Owners of the global securities; DTC’s records will reflect only the identity of the Direct Participants to whose accounts such securities are credited, which may or may not be the Beneficial Owners. The Direct and Indirect Participants will remain responsible for keeping account of their holdings on behalf of their customers.

Conveyance of notices and other communications by DTC to Direct Participants, by Direct Participants to Indirect Participants, and by Direct Participants and Indirect Participants to Beneficial Owners will be governed by arrangements among them, subject to any statutory or regulatory requirements as may be in effect from time to time. Beneficial Owners may wish to take certain steps to augment transmission to them of notices of significant events with respect to the global securities, such as redemptions, tenders, defaults and proposed amendments to the Indenture. Beneficial Owners may wish to ascertain that the nominee holding the global securities for their benefit has agreed to obtain and transmit notices to the Beneficial Owners. In the alternative, Beneficial Owners may wish to provide their names and addresses to the registrar and request that copies of notices be provided directly to them.

Any redemption notices will be sent to DTC. If less than all of a series of global securities are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each Direct Participant to be redeemed.

Neither DTC nor Cede & Co. (nor any other DTC nominee) will consent or vote with respect to securities unless authorized by a Direct Participant in accordance with DTC’s procedures. Under its usual procedures, DTC mails an Omnibus Proxy (the “Omnibus Proxy”) to us as soon as possible after the record date. The Omnibus Proxy assigns Cede & Co.’s consenting or voting rights to those Direct Participants to whose accounts the securities are credited on the record date (identified in a listing attached to the Omnibus Proxy).

Principal and interest payments, distributions and dividend payments and redemption proceeds, if any, on the global securities will be made to Cede & Co. or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit Direct Participants’ accounts upon DTC’s receipt of funds and corresponding detail information from the trustee or agent on the payment date in accordance with their respective holdings shown on DTC’s records. Payments by Direct and Indirect Participants to Beneficial Owners will be governed by standing instructions and customary practices, as is the case with securities held for the accounts of customers in bearer form or registered in “street-name,” and will be the responsibility of such Participants and not of DTC, the trustee or agent for such securities or us, subject to any statutory or regulatory requirements as may be in effect from time to time. Payment of principal, premium, if any, interest, distributions and dividend payments and redemption proceeds, if any, to Cede & Co. (or such other nominee as may be requested by an authorized representative of DTC) is the responsibility of the appropriate trustee or agent and us, disbursement of such payments to Direct Participants is the responsibility of DTC, and disbursement of such payments to the Beneficial Owners is the responsibility of Direct and Indirect Participants.

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The information in this section concerning DTC and DTC’s book-entry system has been obtained from sources, including DTC, that we believe to be reliable, but we take no responsibility for the accuracy thereof.

The underwriters, dealers or agents of any of the securities may be direct participants of DTC.

None of the trustees, us or any agent for payment on or registration of transfer or exchange of any global security will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial interests in such global security or for maintaining, supervising or reviewing any records relating to such beneficial interests.

PLAN OF DISTRIBUTION

We may sell the securities offered pursuant to this prospectus on a continuous or delayed basis:

This prospectus may be used in connection with any offering of securities through any of these methods or other methods described in the applicable prospectus supplement.

The applicable prospectus supplement will set forth the terms under which the securities are offered, including the name or names of any underwriters, dealers or agents, the respective amounts offered, the purchase price of the securities and the proceeds to us from the sale, any underwriting discounts and other items constituting compensation, any initial offering price and any discounts, commissions or concessions allowed or reallowed or paid to dealers.

Any initial offering price and any discounts, concessions or commissions allowed or reallowed or paid to dealers may be changed from time to time.

If underwriters are used in an offering, the securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The securities may be offered to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more of those firms. The specific managing underwriter or underwriters, if any, will be named in the prospectus supplement relating to the particular securities together with the members of the underwriting syndicate, if any. Unless otherwise set forth in the applicable prospectus supplement, the obligations of the underwriters to purchase the particular securities will be subject to certain conditions precedent and the underwriters will be obligated to purchase all of the securities being offered if any are purchased.

We may sell the securities directly or through agents we designate from time to time. The applicable prospectus supplement will set forth the name of any agent involved in the offer or sale of the securities in respect of which such prospectus supplement is delivered and any commissions payable by us to such agent. Unless otherwise indicated in the applicable prospectus supplement, any agent will be acting on a best efforts basis for the period of its appointment.

We may authorize underwriters, dealers or agents to solicit offers by certain institutions to purchase the securities at the public offering price and on the terms described in the related prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future.

Securities may also be offered and sold, if so indicated in the applicable prospectus supplement, in connection with a remarketing upon their purchase, in accordance with a redemption or repayment pursuant to

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their terms, or otherwise, by one or more firms, which we refer to herein as the “remarketing firms,” acting as principals for their own accounts or as our agent. Any remarketing firm will be identified and the terms of its agreement, if any, with us and its compensation will be described in the applicable prospectus supplement. Remarketing firms may be deemed to be underwriters, as that term is defined in the Securities Act of 1933, in connection with the securities remarketed thereby.

Any underwriters, dealers or agents participating in the distribution of the securities may be deemed to be underwriters and any discounts or commissions received by them on the sale or resale of the securities may be deemed to be underwriting discounts and commissions under the Securities Act of 1933. Agents, dealers and underwriters may be entitled, under agreements entered into with us, to indemnification by us against certain liabilities, including liabilities under the Securities Act of 1933, and to contribution with respect to payments which the agents, dealers or underwriters may be required to make in respect of these liabilities. Agents, dealers and underwriters may engage in transactions with or perform services for us in the ordinary course of business.

Unless otherwise specified in a prospectus supplement, the securities will not be listed on a national securities exchange.

We may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and, if not identified in this prospectus, will be identified in the applicable prospectus supplement.

LEGAL MATTERS

Gregory L. Nelson, Esq., our Senior Vice President, General Counsel and Secretary, will pass upon the validity of the offered securities for us. As of March 31, 2012, Mr. Nelson owned 10,268 shares of Ameren common stock as well as 159 shares of Ameren common stock through our 401(k) plan. In addition, as of that date, Mr. Nelson owned 44,899 performance share units, 2,394 of which are fully vested. Pillsbury Winthrop Shaw Pittman LLP, New York, New York, will pass upon the validity of the offered securities for any underwriters, dealers, purchasers or agents. Pillsbury Winthrop Shaw Pittman LLP represents us and our affiliates from time to time in connection with various matters.

EXPERTS

The financial statements of Union Electric Company as of December 31, 2011 and 2010 and for each of the three years in the period ended December 31, 2011 incorporated in this prospectus by reference to the Annual Report on Form 10-K of Union Electric Company for the year ended December 31, 2011, have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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PROSPECTUS

AMEREN ILLINOIS COMPANY

Senior Secured Debt Securities

First Mortgage Bonds

Senior Unsecured Debt Securities

Preferred Stock

Ameren Illinois Company may offer any of the securities described in this prospectus in one or more offerings from time to time in amounts authorized from time to time. This prospectus provides you with a general description of these securities. We will provide specific information about the offering and the terms of these securities in supplements to this prospectus. The supplements may also add, update or change information contained in this prospectus. You should read this prospectus and the supplements carefully before investing. This prospectus may not be used to sell any of these securities unless accompanied by a prospectus supplement.

Unless otherwise indicated in the related prospectus supplement, the securities described in this prospectus will not be listed on a national securities exchange.

Our principal executive offices are located at 300 Liberty Street, Peoria, Illinois 61602 and our telephone number is (309) 677-5271.

Investing in our securities involves risks. Before buying our securities, you should refer to the risk factors included in our periodic reports filed with the Securities and Exchange Commission under the Securities Exchange Act of 1934, which are incorporated by reference into this prospectus, in prospectus supplements relating to specific offerings and in other information that we file with the Securities and Exchange Commission. See “ Risk Factors ” on page 3.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We may offer these securities directly or through underwriters, agents or dealers. Each prospectus supplement will provide the terms of the plan of distribution relating to each series of securities. See “Plan of Distribution.”

The date of this prospectus is June 21, 2012.

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AMEREN ILLINOIS COMPANY

Ameren Illinois Company, doing business as Ameren Illinois, is a subsidiary of Ameren Corporation (“Ameren”), a public utility holding company for Ameren Illinois, Union Electric Company, and various non-rate-regulated subsidiaries. Ameren, headquartered in St. Louis, Missouri, is a public utility holding company under the Public Utility Holding Company Act of 2005, administered by the Federal Energy Regulatory Commission. Ameren Illinois was incorporated in Illinois in 1923 as Central Illinois Public Service Company (“CIPS”). On October 1, 2010, Central Illinois Light Company (“CILCO”) and Illinois Power Company (“IP”) merged with and into CIPS (the “Ameren Illinois Merger”) with the surviving corporation renamed Ameren Illinois Company. Ameren Illinois operates a rate-regulated electric and natural gas transmission and distribution business in Illinois. Ameren Illinois supplies electric and natural gas utility service to portions of central and southern Illinois having an estimated population of 3.1 million in an area of 40,000 square miles. As of December 31, 2011, Ameren Illinois supplied electric service to 1.2 million customers and natural gas service to 809,000 customers.

In this prospectus, “Ameren Illinois,” “we,” “us” and “our” refer to Ameren Illinois Company and, unless the context otherwise indicates, do not include our subsidiaries, if any.

WHERE YOU CAN FIND MORE INFORMATION

We have filed a registration statement on Form S-3 with the Securities and Exchange Commission, or SEC, under the Securities Act of 1933. This prospectus is part of the registration statement, but the registration statement also contains or incorporates by reference additional information and exhibits. We are subject to the informational requirements of the Securities Exchange Act of 1934 and, therefore, we file annual, quarterly and current reports, information statements and other information with the SEC. You may read and copy the registration statement and any document that we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. You can call the SEC’s toll-free telephone number at 1-800-SEC-0330 for further information on the public reference room. The SEC maintains a website at http://www.sec.gov that contains reports, proxy and information statements and other information regarding companies, such as us, that file documents with the SEC electronically. The documents can be found by searching the EDGAR archives of the SEC electronically.

The SEC allows us to “incorporate by reference” the information that we file with the SEC which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus and you should read it with the same care. Later information that we file with the SEC will automatically update and supersede this information and will be deemed to be incorporated by reference into this prospectus (other than any documents, or portions of documents, not deemed to be filed). We incorporate by reference the following documents previously filed with the SEC:

We are also incorporating by reference all additional documents that we file with the SEC under Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934 after the date of this prospectus until the offerings contemplated by this prospectus are completed or terminated.

Any statement contained in this prospectus or in a document incorporated or deemed to be incorporated by reference in this prospectus will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or in any separately filed document which also is or is

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deemed to be incorporated by reference herein modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute part of this prospectus.

You may request a free copy of these filings by writing or telephoning us, c/o Ameren Corporation, at the following address:

Ameren Illinois Company

c/o Ameren Corporation

Attention: Secretary’s Department

P.O. Box 66149

St. Louis, Missouri 63166-6149

Telephone: (314) 621-3222

Copies of these filings are also available from Ameren’s website at http://www.ameren.com. We do not intend this internet address to be an active link or to otherwise incorporate the contents of the website into this prospectus.

You should rely only on the information incorporated by reference or provided in this prospectus or any supplement or in any written communication from us specifying the final terms of a particular offering of securities. We have not authorized anyone else to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information in this prospectus or any supplement is accurate as of any date other than the date on the front of those documents or that the information incorporated by reference is accurate as of any date other than the filing date of the document incorporated by reference. Our business, financial position, results of operations and prospects may have changed since those dates.

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we have filed with the SEC utilizing a “shelf” registration process. Under this shelf registration process, we may sell, at any time and from time to time, in one or more offerings, any of the securities described in this prospectus. We may offer any of the following securities: senior secured debt securities, first mortgage bonds, senior unsecured debt securities and preferred stock (collectively, the “securities”).

This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. Any prospectus supplement may also add, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and the prospectus supplement, you should rely on the information in the prospectus supplement. The registration statement we have filed with the SEC includes exhibits that provide more detail on descriptions of the matters discussed in this prospectus. You should read this prospectus, the registration statement of which this prospectus is a part and the related exhibits filed with the SEC and any prospectus supplement together with additional information described under “Where You Can Find More Information.”

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