OFFERING CIRCULAR NOT FOR GENERAL CIRCULATION IN THE UNITED STATES ENEL — Società per Azioni (incorporated with limited liability in Italy) U.S. $1,250,000,000 Capital Securities due 2073 Enel — Società per Azioni (the “Issuer” or “Enel”) will issue U.S. $1,250,000,000 Capital Securities due 2073 (the “Securities”) on September 24, 2013 (the “Issue Date”). The Securities will bear interest on their principal amount (a) from (and including) the Issue Date to (but excluding) the First Reset Date, at the rate of 8.750 percent per annum and (b) from (and including) the First Reset Date to (but excluding) the Maturity Date, for each Reset Period, the relevant 5-year Swap Rate plus (A) in respect of the Reset Periods commencing on the First Reset Date, September 24, 2028, September 24, 2033 and September 24, 2038, 6.130 percent per annum, and (B) in respect of any other Reset Period, 6.880 percent per annum (each, as defined in “Description of the Securities”). Interest on the Securities will be payable semi- annually in arrears on March 24 and September 24 each year, commencing on March 24, 2014 (each an “Interest Payment Date”). Payment of interest on the Securities may be deferred at the option of the Issuer in certain circumstances, as set out under “Description of the Securities — Interest Deferral”. The Securities will be issued in fully registered form and only in denominations of U.S. $200,000 and in integral multiples of U.S. $1,000 in excess thereof. Unless previously redeemed by the Issuer as provided below, the Issuer will redeem the Securities on September 24, 2073 at their principal amount, together with interest accrued to, but excluding, such date and any Arrears of Interest (as defined in “Description of the Securities”). The Issuer may redeem all of the Securities, but not some only, on any Reset Date, in each case at their principal amount together with any interest accrued up to, but excluding, the relevant Reset Date and any Arrears of Interest. The Issuer may also redeem all, but not some only, of the Securities at the applicable Early Redemption Price at any time upon the occurrence of a Withholding Tax Event, an Accounting Event, a Rating Methodology Event or a Tax Deductibility Event (each as defined in “Description of the Securities”). In the event that at least 90 percent of the aggregate principal amount of the Securities issued on the Issue Date has been purchased by or on behalf of the Issuer or a Subsidiary of the Issuer (as defined in “Description of the Securities”) and cancelled, the Issuer may redeem all, but not some only, of the outstanding Securities at the applicable Early Redemption Price. See “Description of the Securities — Purchases and Substantial Repurchase Event”). The Securities constitute direct, unsecured and subordinated obligations of the Issuer and rank and will at all times rank pari passu without any preference among themselves and with Parity Securities and senior only to Junior Securities. The Securities will not be guaranteed. An investment in the Securities involves certain risks. For a discussion of risks, see “Risk Factors,” beginning on page 20. This Offering Circular has been approved by the Central Bank of Ireland (the “Central Bank”), as competent authority under the Prospectus Directive 2003/71/EC, as amended (the “Prospectus Directive”). The Central Bank only approves this Offering Circular as meeting the requirements imposed under Irish and EU law pursuant to the Prospectus Directive. Such approval relates only to Securities which are to be admitted to trading on the regulated market of the Irish Stock Exchange or other regulated markets for the purposes of Directive 2004/39/EC or which are to be offered to the public in any member state of the European Economic Area. Application has been made to the Irish Stock Exchange for the Securities to be admitted to the Official List and trading on its regulated market. The Managers (as defined herein) are offering the Securities to qualified institutional buyers (“QIBs”) in reliance on Rule 144A under the U.S. Securities Act of 1933, as amended (the “Securities Act”). The Securities will be issued pursuant to the terms of the indenture dated September 24, 2013 (the “Indenture”) among the Issuer and Citibank, N.A., London Branch, as Trustee (the “Trustee”). The Securities will be evidenced by Global Securities (the “Global Securities”) registered in the name of Monte Titoli S.p.A. (“Monte Titoli”), as operator of the Italian central securities clearing system for credit of the Securities evidenced thereby to accounts of Monte Titoli participants, and will be issued in dematerialized form in Monte Titoli. Initially, all of the Securities will be credited to a third-party securities account in Monte Titoli of Citibank, N.A., London Branch, as Receipt Issuer (the “Receipt Issuer”). The Receipt Issuer will issue and deliver Receipts (“Receipts”) representing the book-entry interests in the Global Securities it holds on deposit and evidenced by Global Receipts in registered form (the “Global Receipts”) to The Depository Trust Company (“DTC”) for credit to the accounts of DTC’s participants. Citibank, N.A., London Branch will hold the Global Receipts as custodian for DTC, and the Global Receipts will be registered in the name of Cede & Co., as DTC’s nominee, for the benefit of DTC’s participants. Transfers of beneficial interests in the Global Receipts will be shown on, and will be effected only through, records maintained in book-entry form by DTC or any other securities intermediary holding an interest directly or indirectly through DTC. After the initial placement of the Receipts, holders of Receipts who are QIBs will have the right, subject to the terms of the Deposit Agreement (as hereinafter defined) for the Receipts and the Tax Certification Procedures (as hereinafter defined), to request conversion of the Receipts into the corresponding Securities to be held in accounts by QIBs at participants at Monte Titoli that are “second level banks” (as defined in Italian Legislative Decree No. 239 dated April 1, 1996, as the same may be amended or supplemented from time to time, “Decree No. 239”), including Euroclear Bank SA/NV (“Euroclear”) and Clearstream Banking, Luxembourg (“Clearstream”), or that employ the services of an Italian Tax Representative (as such term is defined in Decree No. 239) (both herein referred to as a “Second-level Bank”). Similarly, QIBs will be able, subject to the terms of the Deposit Agreement and the Tax Certification Procedures, to convert their Securities into the corresponding Receipts to be held in an account at DTC. See “Description of the Receipts and the Deposit Agreement.” Italian law requires financial institutions performing the duties of Second-level Banks to obtain from each eligible beneficial owner (as referred to in Decree No. 239) a certification of its eligibility to receive interest, premium and other income in respect of the Securities free from Italian substitute tax (imposta sostitutiva) upon the investor’s first purchase of a beneficial interest in the Securities (either at the time of the issuance of Securities or, if purchased thereafter, upon a purchase of Securities in the secondary market), and to make that certification available to the Italian tax authorities. There are no ongoing certification requirements for investors following the initial certification of eligibility, subject, in the case of Securities represented by Receipts, to compliance with the Acupay Italian tax compliance and relief procedures described in “Annex B — Acupay Italian Tax Compliance and Relief Procedures” (the “Tax Certification Procedures”) by them and their Financial Intermediaries (as defined below). Enel has arranged certain procedures with Acupay System LLC (“Acupay”) and Monte Titoli to facilitate the collection of certifications from beneficial owners of Receipts through the relevant securities brokers and dealers, banks, trust companies, and clearing corporations that clear through DTC or maintain a direct or indirect custodial relationship with a DTC Participant (as defined in “Description of the Securities”) (such direct or indirect participants in DTC, the “Financial Intermediaries”). In connection with such Tax Certification Procedures applicable to the Receipts, Monte Titoli will, as Italian Tax Representative, perform the functions of Second-level Bank in relation to all of the Securities represented by Receipts. Italian substitute tax at the then-applicable rate (currently 20.0%) will be withheld from interest (including the accrual of original issue discount) and redemption premium (if any) arising in respect of the Securities received by any investor that is not, or ceases to be, eligible to receive interest free of Italian substitute tax in respect of the Securities (including, in the case of investors holding Receipts, because of any failure of the Tax Certification Procedures or that fails, or whose Financial Intermediaries fail, to comply with the Tax Certification Procedures). Such withholding will be applied to income received by such investor from payments made by the Issuer, as well as to accrued interest received by such investor incidentally in connection with the transfer of beneficial interests in the Securities. The Issuer will not pay any additional amounts in respect of any such withholding. In addition, an investor that is not, or ceases to be, eligible to receive interest free of Italian substitute tax in respect of the Securities or does not comply (either