SUPPLEMENT dated 20 th September, 2005 To the Debt Issuance Programme Prospectus of SOCIÉTÉ GÉNÉRALE (incorporated in France) and SGA SOCIÉTÉ GÉNÉRALE ACCEPTANCE N.V. (incorporated in The Netherlands Antilles) dated 1 st July, 2005 (updated as of 8 th August, 2005) as supplemented by the Supplement dated August 24 th, 2005, the second Supplement dated 7 th September, 2005 and the third Supplement dated 16 th September, 2005 This Supplement supersedes and replaces the Supplement dated 16 th September, 2005. This document constitutes a Supplement of the Prospectus and any amendments or supplements thereto, for the purposes of Article 16 of the Prospectus Directive and must be read in conjunction with such Debt Issuance Programme Prospectus, as amended and/or supplemented. Full information on the Issuer and the offer of the Notes is only available on the basis of the combination of this Supplement and the Prospectus, as amended and/or supplemented. Copies of such Prospectus, and any amendments or supplements thereto and this Supplement are available at www.bourse.lu and from the head office of the Issuer and the specified offices of the Paying Agents. Terms used herein shall be deemed to be defined as such for the purposes of the Conditions set forth in the Debt Issuance Programme Prospectus dated 1 st July, 2005 (updated as of 8 th August, 2005) (the Prospectus) and any amendments or supplements thereto, which together constitute a base prospectus for the purposes of the Prospectus Directive (Directive 2003/71/EC), approved by the Commission de Surveillance du Secteur Financier on 9 th August, 2005 in accordance with article 7 of the Luxembourg law on prospectuses for securities implementing article 13 of Directive 2003/71/EC of the European Parliament and of the Council of 4 November 2003 on the prospectus to be published when securities are offered to the public or admitted to trading and amending Directive 2001/34/EC (the Prospectus Directive). For Indexed Notes payments (whether in respect of principal and/or interest and whether at maturity or otherwise) calculated by reference to the price of gold, precious metals, commodities or futures contract on the same, the following commodities technical annex (the Commodities Technical Annex) supplements the Prospectus. The Commodities Technical Annex will apply to Final Terms relating to a particular issue of Notes, if such Final Terms bear the following : The provisions of the Commodities Technical Annex apply to these Final Terms and such documents shall be read together. In the event of inconsistency between the Commodities Technical Annex and these Final Terms, these Final Terms will prevail. Commodities Technical Annex The following shall, if stated to be applicable in the Final Terms, form part of the terms and conditions of the Notes in the same way, mutatis mutandis as the section Terms and Conditions of the Notes commencing on page 50 of the Prospectus. 1) Commodity Reference Price Commodity Reference Price means any of the following prices for the relevant Commodity: AL means the settlement price per tonne of high grade Primary Aluminium at the end of the second morning ring on the LME for cash delivery, stated in USD, as determined by the LME and displayed on page "MTLE" of the Reuters Monitor Money Rates Service.
BL means the settlement price per barrel of the Brent blend crude oil on the IPE of the futures contract for delivery on the Delivery Date, stated in USD, as made public by the IPE and displayed on page "SETT" of the Reuters Monitor Money Rates Service or on the Bloomberg ticker CO1+Cmdty provided that, on any Valuation Date or Pricing Date, the Delivery Date with respect to the relevant futures contract shall mean the month of expiration of the first futures contract to expire following that date (the First Nearby Month Futures Contract), except that for the last day of quotation for the First Nearby Month Futures Contract the Delivery Date of the relevant futures contract shall be the month of expiration of the second futures contract to expire following that date (the Second Nearby Month Futures Contract) (e.g. for a Valuation Date occurring on September 30, 2005, the relevant settlement price per barrel of the Brent blend crude oil of the futures contract, stated in USD, as made public by the IPE and displayed on page "SETT" of the Reuters Monitor Money Rates Service or on the Bloomberg ticker CO1+Cmdty, shall be that of the November 05 Brent blend crude oil futures contract expiring on October 14, 2005, provided that for a Valuation Date occurring on October 14, 2005, the relevant price shall be that of the December 05 Brent blend crude oil futures contract). CL means the settlement price per barrel of the West Texas Intermediate light sweet crude oil on the NYMEX of the futures contract for delivery on the Delivery Date, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service or on the Bloomberg ticker CL1+Cmdty, provided that, on any Valuation Date or Pricing Date, the Delivery Date with respect to the relevant futures contract shall mean, unless otherwise provided in the applicable Final Terms, the month of expiration of the first futures contract to expire following that date (the First Nearby Month Futures Contract) (e.g., unless otherwise provided in the applicable Final Terms, for a Valuation Date occurring on September 30, 2005, the relevant settlement price per barrel of the West Texas Intermediate light sweet crude oil of the futures contract, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service or on the Bloomberg ticker CL1+Cmdty, shall be that of the November 05 West Texas Intermediate light sweet crude oil futures contract expiring on October 20, 2005). CU means the settlement price per tonne of copper Grade A at the end of the second morning ring on the LME for cash delivery, stated in USD, as determined by the LME and displayed on page "MTLE" of the Reuters Monitor Money Rates Service. GL means the settlement price per metric ton of gas oil on the IPE of the futures contract for delivery on the Delivery Date, stated in USD, as made public by the IPE and displayed on page "SETT" of the Reuters Monitor Money Rates Service, provided that, on any Valuation Date or Pricing Date, the Delivery Date with respect to the relevant futures contract shall mean the month of expiration of the first futures contract to expire following that date (the First Nearby Month Futures Contract), except that for the last day of quotation for the First Nearby Month Futures Contract the Delivery Date of the relevant futures contract shall be the month of expiration of the second futures contract to expire following that date (the Second Nearby Month Futures Contract) (e.g. for a Valuation Date occurring on September 30, 2005, the relevant settlement price per metric ton of gas oil on the IPE of the futures contract, stated in USD, as made public by the IPE and displayed on page "SETT" of the Reuters Monitor Money Rates Service, shall be that of the October 05 metric ton of gas oil futures contract expiring on October 12, 2005, provided that for a Valuation Date occurring on October 12, 2005, the relevant price shall be that of the November 05 metric ton of gas oil futures contract). GO means the morning or afternoon (as specified in the applicable Final Terms) Gold fixing price per troy ounce of Gold for delivery in London through a member of the LBMA authorised to effect such delivery, stated in USD, as determined by the London Gold Market and displayed on page "GOFO" of the Reuters Monitor Money Rates Service. HO means the settlement price per U.S. gallon of New York Harbor No. 2 heating oil on the NYMEX of the futures contract for delivery on the Delivery Date, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service, provided that, on any Valuation Date or Pricing Date, the Delivery Date with respect to the relevant futures contract shall mean, unless otherwise provided in the applicable Final Terms, the month of expiration of the first futures contract to expire following that date (the First Nearby Month Futures Contract) (e.g. for a Valuation Date occurring on September 30, 2005, the relevant settlement price per U.S. gallon of New York Harbor No. 2 heating oil on the NYMEX of the futures contract, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service, shall be that of the October 05 U.S. gallon of New York Harbor No. 2 heating oil futures contract expiring on September 30, 2005). 2
HU means the settlement price per U.S. gallon of New York Harbor unleaded gasoline on the NYMEX of the first nearby futures contract for delivery on the Delivery Date, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service, provided that, on any Valuation Date or Pricing Date, the Delivery Date with respect to the relevant futures contract shall mean, unless otherwise provided in the applicable Final Terms, the month of expiration of the first futures contract to expire following that date (the First Nearby Month Futures Contract) (e.g. for a Valuation Date occurring on September 30, 2005, the relevant settlement price per U.S. gallon of New York Harbor unleaded gasoline on the NYMEX of the futures contract, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service, shall be that of the October 05 U.S. gallon of New York Harbor unleaded gasoline futures contract expiring on September 30, 2005). Deleted: NG means the settlement price per MMBTU of natural gas on the NYMEX of the Henry Hub Natural Gas futures contract for delivery on the Delivery Date, stated in USD, as made public by the NYMEX and displayed on page "SETNGS" of the Reuters Monitor Money Rates Service, provided that, on any Valuation Date or Pricing Date, the Delivery Date with respect to the relevant futures contract shall mean, unless otherwise provided in the applicable Final Terms, the month of expiration of the first futures contract to expire following that date (the First Nearby Month Futures Contract) (e.g. for a Valuation Date occurring on September 30, 2005, the relevant settlement price per MMBTU of natural gas on the NYMEX of the futures contract, stated in USD, as made public by the NYMEX and displayed on page "SETT" of the Reuters Monitor Money Rates Service, shall be that of the November 05 MMBTU of natural gas futures contract expiring on October 27, 2005). NI means the settlement price per tonne of Primary Nickel at the end of the second morning ring on the LME for cash delivery, stated in USD, as determined by the LME and displayed on page "MTLE" of the Reuters Monitor Rates Service. PB means the settlement price per tonne of the Standard Lead at the end of the second morning ring on the LME for cash delivery, stated in U.S. dollars, as determined by the LME and displayed on page "MTLE" of the Reuters Monitor Money Rates Service. PD means the afternoon Palladium fixing price per troy ounce gross of Palladium for delivery in Zurich through a member of the LPPM authorized to effect such delivery, stated in U.S. dollars, as calculated by the LPPM and displayed on page "STBL" of the Reuters Monitor Money Rates Service. PT means the morning or afternoon (as specified in the applicable Final Terms) Platinum fixing price per troy ounce gross of Platinum for delivery in Zurich through a member of the LPPM authorised to effect such delivery, stated in USD, as calculated by the LPPM and displayed on page "STBL" of the Reuters Monitor Money Rates Service. SI means the Silver fixing price per troy ounce of Silver for delivery in London through a member of the LBMA authorised to effect such delivery, stated in USD, as calculated by the London Silver Market and displayed on page "SIFO" of the Reuters Monitor Money Rates Service. ZN means the settlement price per tonne of Special High Grade Zinc at the end of the second morning ring on the LME for cash delivery, stated in USD, as determined by the LME and displayed on page "MTLE" of the Reuters Monitor Rates Service. AL (f), BL (f), CL (f), CU (f), GL (f), GO (f), HO (f), HU (f), NG (f), NI (f), PB (f), PD (f), PT (f), SI (f) and ZN (f), means PD, PT, SI and ZN on the Final Valuation Date. AL (i), BL (i), CL (i), CU (i), GL (i), GO (i), HO (i), HU (i), NG (i), NI (i), PB (i), PD (i), PT (i), SI (i) and ZN (i), means PD, PT, SI and ZN on the Initial Valuation Date. AL (n), BL (n), CL (n), CU (n), GL (n), GO (n), HO (n), HU (n), NG (n), NI (n), PB (n), PD (n), PT (n), SI (n) and ZN (n), means PD, PT, SI and ZN on a Valuation Date (n). 3
2) Exchange and Principal Trading Markets Exchange means any of LME, IPE, APX, COMEX, KSCBT, LBMA, LPPM, NORDPOOL, NYMEX, OMLX and SIMEX as specified in the applicable Final Terms. APX means the Amsterdam Power Exchange N.V. or its successor. COMEX means the Commodity Exchange Inc., New York or its successor. IPE means The International Petroleum Exchange of London Ltd. or its successor. KSCBT means the Kansas City Board of Trade or its successor. LBMA means The London Bullion Market Association or its successor. LME means the London Metal Exchange Limited or its successor. LPPM means The London Platinum and Palladium Market or its successor. NORDPOOL means the Nord Pool ASA (The Nordic Power Exchange) or its successor. NYMEX means the New York Mercantile Exchange or its successor. OMLX means the OM London Exchange Ltd. or its successor. SIMEX means The Singapore International Monetary Exchange, Inc. or its successor. 3) Other Definitions Barrier Level means the level specified as such in the applicable Final Terms. Basket means a basket of commodities determined by the Calculation Agent in accordance with the formula specified in the applicable Final Terms. Commodity means any commodity specified in the applicable Final Terms. Commodity Business Day means a day other than a Saturday or a Sunday on which the Commodity Reference Price of the relevant Commodity is published. Final Valuation Date means the date specified in the applicable Final Terms, subject to the definition of Valuation Date (n). Initial Valuation Date means the date specified in the applicable Final Terms, subject to the definition of Valuation Date (n). ISDA Definitions means the 1993 ISDA Commodity Derivatives Definitions (as supplemented by the 2000 Supplement) and the 1997 ISDA Bullion Definitions published by the International Swaps and Derivatives Association, Inc. Knock-In Level means the level specified as such in the applicable Final Terms. Knock-Out Level means the level specified as such in the applicable Final Terms. Market Disruption Event means, in respect of a Commodity, an event defined as such or as an Additional Market Disruption Event under the ISDA Definitions including, but not limited to, (i) the failure by the relevant Exchange to announce or publish the price of such Commodity, or the temporary or permanent discontinuance or unavailability of the price source, (ii) the material suspension of trading in such Commodity on the Exchange, (iii) the failure of trading to commence, or the permanent discontinuation of trading, in such Commodity on the 4
relevant Exchange or the disappearance of, or of trading in, such Commodity, (iv) the occurrence since the first Valuation Date of a material change in the formula for or the method of calculating the price of such Commodity, (v) the occurrence since the first Valuation Date of a material change in the content, composition or constitution of such Commodity and (vi) the material limitation imposed on trading in such Commodity on the Exchange. MMBTU means one million British thermal units. Observation Period unless otherwise specified in the applicable Final Terms, means the period from and including the first Valuation Date to and including the last Valuation Date. Pricing Date means a Commodity Business Day on which there is no Market Disruption Event. Strike Price means the price specified as such in the applicable Final Terms. Valuation Date(s) (n) means the Initial Valuation Date and the Final Valuation Date, as the case may be and/or the date(s) specified as such in the applicable Final Terms, PROVIDED THAT, if any of such dates is not a Pricing Date for any Commodity, then, the Calculation Agent, shall determine, in good faith, the fair market value of such Commodity which will reflect the conditions prevailing on the market on such day, taking into consideration the latest available quotation for such Commodity and any other information that in good faith it deems relevant, such as the Disruption Fallbacks described in the ISDA Definitions. RESPONSIBILITY Each Issuer accepts responsibility for the information contained in this Supplement. Information or summaries of information included herein with respect to the Underlying(s), has been extracted or obtained, as the case may be, from general databases released publicly or by any other available information. Each Issuer confirms that such information has been accurately reproduced or summarised and that so far as they are aware and able to ascertain from information published on these general data bases, no facts have been omitted which would render the reproduced or summarised information inaccurate or misleading. Signed on behalf of Société Générale: By: Duly authorised Signed on behalf of SGA Société Générale Acceptance N.V.: By: Duly authorised 5