Gas Natural Fenosa Finance B.V. (incorporated with limited liability under the laws of The Netherlands and having its statutory domicile in Amsterdam) €1,000,000,000 UNDATED 8 YEAR NON-CALL DEEPLY SUBORDINATED GUARANTEED FIXED RATE RESET SECURITIES unconditionally and irrevocably guaranteed on a subordinated basis by Gas Natural SDG, S.A. (incorporated with limited liability under the laws of the Kingdom of Spain) The €1,000,000,000 Undated 8 Year Non-Call Deeply Subordinated Guaranteed Fixed Rate Reset Securities (the “Securities”) are issued by Gas Natural Fenosa Finance B.V. (the “Issuer”) and unconditionally and irrevocably guaranteed on a subordinated basis by Gas Natural SDG, S.A. (the “Guarantee”, and the “Guarantor” or “Gas Natural SDG”, respectively). Pursuant to the terms and conditions of the Securities as described in “Terms and Conditions of the Securities” (the “Conditions”), the Securities will bear interest on their principal amount (i) at a fixed rate of 4.125 per cent. per annum from (and including) the Issue Date to (but excluding) the First Reset Date (as defined in the Conditions) payable annually in arrear on 18 November in each year, with the first Interest Payment Date (as defined below) commencing on 18 November 2015; and (ii) from (and including) the First Reset Date (as defined in the Conditions), at the applicable 8 year Swap Rate in respect of the relevant Reset Period, plus: (A) in respect of the period commencing on the First Reset Date to (but excluding) 18 November 2024, 3.353 per cent. per annum; (B) in respect of the period commencing on 18 November 2024 to (but excluding) 18 November 2042, 3.603 per cent. per annum; and (C) from and including 18 November 2042, 4.353 per cent. per annum, all as determined by the Agent Bank (as defined in the Conditions), payable annually in arrear on 18 November in each year (each, an “Interest Payment Date”, as defined in the Conditions), commencing on 18 November 2023. The Issuer may, at its sole discretion, elect to defer (in whole or in part) any payment of interest on the Securities, as more particularly described in the “Terms and Conditions of the Securities—Optional Interest Deferral”. Any amounts so deferred, together with further interest accrued thereon (at the Prevailing Interest Rate applicable from time to time), shall constitute Arrears of Interest (as defined in the Conditions). The Issuer may pay outstanding Arrears of Interest, in whole or in part, at any time in accordance with the Conditions. Notwithstanding the foregoing, the Issuer shall pay any outstanding Arrears of Interest in whole, but not in part, on the first occurring Mandatory Settlement Date following the Interest Payment Date on which any outstanding Arrears of Interest was first deferred, all as more particularly described in “Terms and Conditions of the Securities—Optional Interest Deferral— Mandatory Settlement of Arrears of Interest”. - i - The Securities will be undated securities in respect of which there is no specific maturity date and shall be redeemable (at the option of the Issuer) in whole, but not in part, on the applicable First Reset Date (as defined in the Conditions) or upon any Interest Payment Date thereafter, at their principal amount together with any accrued and unpaid interest up to (but excluding) the Redemption Date (as defined in the Conditions) and any outstanding Arrears of Interest (including any Additional Interest Amounts thereon). In addition, upon the occurrence of an Accounting Event, a Capital Event, a Tax Event, a Withholding Tax Event, or a Substantial Purchase Event (each such term as defined in the Conditions), the Securities will be redeemable (at the option of the Issuer) in whole, but not in part, at the amount set out, and as more particularly described, in “Terms and Conditions of the Securities—Redemption and Purchase”. The Securities will constitute direct, unsecured and subordinated obligations of the Issuer and will at all times rank pari passu and without any preference among themselves, all as more particularly described in “Terms and Conditions of the Securities—Status and Subordination of the Securities and Coupons”. The payment obligations of the Guarantor under the Guarantee will constitute direct, unsecured and subordinated obligations of the Guarantor and will at all times rank pari passu and without any preference among themselves. In the event of the Guarantor being declared in insolvency under Spanish Insolvency Law (as defined below), the rights and claims of Holders (as defined in the Conditions) against the Guarantor in respect of or arising under the Guarantee will rank, as against the other obligations of the Guarantor, in the manner more particularly described in “Terms and Conditions of the Securities— Guarantee, Status and Subordination of the Guarantee”. Payments in respect of the Securities will be made without withholding or deduction for, or on account of, any present or future taxes, duties, assessments or governmental charges of whatever nature of The Netherlands or the Kingdom of Spain, unless such withholding or deduction is required by law. In the event that any such withholding or deduction is made, additional amounts will be payable by the Issuer or, as the case may be, the Guarantor, subject to certain exceptions as are more fully described in “Terms and Conditions of the Securities—Taxation”. Application has been made to the Commission de Surveillance du Secteur Financier (the “CSSF”) in its capacity as competent authority under the Luxembourg Act dated 10 July 2005 relating to prospectuses for securities, as amended (the “Luxembourg Act”), for the approval of this Prospectus for the purposes of Directive 2003/71/EC, as amended, to the extent that such amendments have been implemented in the relevant Member State of the European Economic Area (the “Prospectus Directive”). The CSSF assumes no responsibility for the economic and financial soundness of the transactions contemplated by this Prospectus or the quality or solvency of the Issuer in accordance with Article 7(7) of the Luxembourg Act. This Prospectus constitutes a prospectus for the purposes of Article 5.3 of the Prospectus Directive and the Luxembourg Act. Application has been made to the Luxembourg Stock Exchange for the Securities to be admitted to trading on the Luxembourg Stock Exchange’s regulated market (which is a regulated market for the purposes of the Markets in Financial Instruments Directive 2004/39/EC) and to be listed on the official list of the Luxembourg Stock Exchange. The Securities have not been, and will not be, registered under the United States Securities Act of 1933 (the “Securities Act”) and are subject to United States tax law requirements. The Securities are being offered outside the United States by the Joint Bookrunners (as defined in “Subscription and Sale”) in accordance with Regulation S under the Securities Act (“Regulation S”), and may not be offered, sold or delivered within the United States or to, or for the account or benefit of, U.S. persons except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act. - ii - The Securities will be in bearer form and each in the denomination of €100,000. Each series of Securities will initially be represented by a temporary global security (the “Temporary Global Security”), without interest coupons or talons, which will be deposited with a common depositary on behalf of Euroclear Bank SA/NV (“Euroclear”) and Clearstream Banking, Société Anonyme (“Clearstream, Luxembourg”) on or about the Issue Date. Interests in each Temporary Global Security will be exchangeable for interests in a permanent global security (the “Permanent Global Security” and together with the Temporary Global Security, the “Global Securities”) in the circumstances set out in each Temporary Global Security. Each Permanent Global Security will be exchangeable for definitive Securities (the “Definitive Securities”) in the circumstances set out in the relevant Permanent Global Security. See “Summary of Provisions relating to the Securities in Global Form”. The Securities are expected to be rated BB+ by Standard & Poor’s Credit Market Services Europe Limited (“S&P”), Ba1 by Moody’s Investors Service Limited (“Moody’s”) and BBB– by Fitch Ratings Limited (“Fitch”). Each of S&P, Moody’s and Fitch is established in the European Union and registered under Regulation (EU) No 1060/2009, as amended (the “CRA Regulation”). A security rating is not a recommendation to buy, sell or hold securities and may be subject to suspension, reduction or withdrawal at any time by the assigning rating agency. Prospective investors should have regard to the factors described under the section headed “Risk Factors” in this Prospectus. Joint Bookrunners Banco Bilbao Vizcaya Argentaria, S.A. Barclays BNP PARIBAS CaixaBank JP Morgan Nomura Santander Global Banking & Markets Banca IMI ING Citigroup MUFG Société Générale Corporate & Investment Banking 13 November 2014 - iii - TABLE OF CONTENTS Page IMPORTANT NOTICES....................................................................................................................... 2 RISK FACTORS.................................................................................................................................... 4 OVERVIEW OF THE SECURITIES .................................................................................................... 28 INFORMATION INCORPORATED BY REFERENCE.....................................................................