Exhibit 4.3  SHAREHOLDERS AGREEMENT  In
Madrid on June 13, 2001.  APPEAR  Mr.
Rafael Miranda Robredo, of Spanish nationality, of legal age, with address in
Madrid at Calle Príncipe de Vergara 187, holding National Identification Card
number 13045173-X.  Mr.
José Manuel Arrojo Botija, of Spanish nationality, of legal age, with address
in Madrid at calle Marcelino Santa María number 7, holding National
Identification Card number 51628104.  ACTING  The former,
in the name and on behalf of the company Endesa, S.A., with registered offices in Madrid at Calle Príncipe de
Vergara number 187, incorporated for an indefinite term by virtue of a public
deed authorized by the Notary Public of Madrid, Mr. Rafael López de Haro y Moya
on July 19, 1944 and duly recorded in the Companies Registry of Madrid in
volume 736, folio 196, page 434, with Tax Identification Code Number A-28023430
(hereinafter referred to as Endesa).  In
his position as Chief Executive Officer of the Company, pursuant to the public
deed authorized on May 5, 2000 by the Public Notary of Madrid, Mr.
Santiago Rubio Liniers, with number 855 of his records and duly recorded in the
Companies Registry of Madrid in Volume 14779, folio 46, page M-6405.  The latter,
in the name and on behalf of the company Banco Santander-Central Hispano S.A. with registered offices in
Santander at Paseo de Pereda 9-12 and incorporated by the merger by take-over
of the Banco Central Hispanoamericano by the Banco de Santander, pursuant to
the public deed of April 13, 1999, authorized by the Public Notary Mr.
Antonio Fernandez-Golfín Aparicio, with number 1212 of his records and recorded
in the Companies Registry of Cantabria in volume 676, page S-1960, folio 28
(hereinafter referred to as BSCH).  In
his position as attorney-in-fact for the company by virtue of the public deed
authorized on February 26, 1999 by Mr. José María Prada Diez, Notary
Public of Santander, with number 643 of his records. His authority is completed
by the agreement adopted by the Delegated Risk Commission on June 7, 2001.  The
appearing parties, in the positions in which they act, mutually and
reciprocally acknowledge that they hold the required legal authority to enter
into this document and, for such purpose hereby  WITNESSETH  ONE:
Whereas the Italian Company ENEL, S.p.A. (hereinafter Enel) has initiated a
procedure for the sale of 100% of its shares in the Company Elettrogen,
S.p.A. (hereinafter Elettrogen) as sole shareholder, establishing the rules of
said process in letters sent to potential buyers on December 18, 2000,
March 7, 2001, May 18, 2001, and May 27, 2001 (all of them, as a
whole hereinafter referred to as the Rules of Procedure).  TWO:
Whereas in accordance with the Rules of Procedure, Endesa has been selected to
participate in the final phase of the process of the sale of Elettrogen, and
prior to this document, has individually submitted a non-binding offer for the
acquisition of this company.  In
this Non-binding offer, Endesa informed Enel of the possibility of its
submitting a Binding Offer jointly with one or more companies, forming what the
Rules of Procedure call a Consortium.  In
this communication to Enel, Endesa stated that in all cases, it would be
considered the strategic industrial reference shareholder of Elettrogen if it
was selected in the purchase process of this company.  THREE:
Whereas on May 31, 2001, Endesa and BSCH signed a letter of intent, by
virtue of which, among other aspects, the latter agreed to form part of the
Consortium led by the former, for the purpose of submitting a Binding Offer for
the acquisition of the share capital of Elettrogen.  
   In
accordance with the indications of the previous paragraph, on June 1,
2001, Endesa, S.A. notified Enel of its intention to submit a Binding Offer,
forming a Consortium with the companies BSCH, and the Italian company ASM
Brescia, S.p.A. (hereinafter ASM) with which it had previously signed a letter
of intent.  The
Binding Offer is expected to be submitted on June 15, 2001, and all of the
documents that comprise it, in accordance with the rules of procedure, must be
signed by all of the members of the Consortium, who shall be jointly and
severally liable, and by the common representative of all of the members of the
Consortium, who shall be a person from Endesa designated by all of the
members.  This notwithstanding, Endesa,
in all cases, reserves the possibility of not submitting the Binding Offer in
question, holding BSCH harmless for any consequences that could possibly arise
from this decision.  FOUR:
Whereas if the Binding Offer submitted by the Consortium led by Endesa is
accepted in the process of sale of Enel in accordance with the rules of
procedure, it will be necessary  (I)to pay 5% of the price of the
Binding Offer at the time that the selection of the Binding Offer is
communicated, and  (II)pay the remaining 95% of the
price once the operation has been closed, when the necessary authorization by
the corresponding fair-trade authorities is obtained (hereinafter, the
Closing).  Enel
shall have 90 days, beginning on June 15, 2001, to select one of the
offers for the acquisition of Elettrogen that have been submitted.  FIVE:  Whereas likewise, if the Consortiums Offer
is accepted, it has been deemed convenient to establish a company in accordance
with Italian law (hereinafter, Newco), with the members of said Consortium s
participating in the share capital of the new company in the same proportion as
their participation in the Consortium.  SIX:  Whereas by virtue of all of that has been
specified in the preceding paragraphs, Endesa and BSCH (hereinafter jointly
referred to as the Parties, and each individually as the Party, recognize
that there are several questions of common interest for them that they consider
to require specific and concrete regulation prior to taking a share in the
Newco, if it is established according to the terms indicated in the preliminary
Clauses of this document, and whose scope exceeds the strict limits of the
articles of incorporation of Newco.  By
virtue of all that has heretofore been expressed, the parties mutually
recognize full legal powers to sign this document and to enter a binding
agreement, in the exercise of the representative powers that they hold, in
accordance with the following  CLAUSES  1INCORPORATION AND SHAREHOLDING IN
THE SHARE CAPITAL OF NEWCO  1.1If the Binding Offer for the
acquisition of 100% of the share capital of Elettrogen submitted by the
Consortium is accepted, by virtue of this document, Endesa and BSCH, jointly
with ASM, agree to establish an Italian corporation, for the purposes of this
document, called Newco.  Newco shall be the company through which, in accordance with
the Rules of Procedure, the members of the Consortium will acquire the shares
of Elettrogen, under the terms and conditions specified in the following
sections, consequently requiring the parties, for the purposes of the full
effectiveness hereof, to issue all public and private documents that may be
required and in general, to carry out all actions that may be necessary in this
sense.  1.2The Establishment of Newco shall
take place during the period of time between when the Consortium receives
notification that its Offer has been selected and the Closing.  The parties recognize that Endesa will coordinate all of the
formalities and processes required to establish Newco within the aforementioned
time period with the legal advisors, Notary, and other Italian authorities,
with BSCH expressly required to collaborate with and assist Endesa in all
necessary aspects, specifically by providing documentation and attending
Shareholders Meetings, Board Meetings, and other actions by the legal
representatives of BSCH that may be necessary. 
BSCH will make no  2 
   payment for the expenses generated as a result of the
actions or processes to which this section refers.  Endesa will request the assistance of BSCH in the terms
specified in the preceding paragraph with sufficient prior notice, which under
no circumstances shall be less than three days.  1.3Endesa and BSCH will acquire,
respectively, a percentage of the share capital of Newco that is proportional
to their participation in the Consortium.  The Binding Offer will specify the
exact percentage of the participation of each one of the Consortium members in
the Consortium, which will be communicated to BSCH on the workday following the
submission of the offer in question.  The parties expressly recognize that
the determination of the exact amount and terms of the disbursement of capital
shall be determined by the financing structure that Endesa defines for the
acquisition of Elettrogen at the time the Binding Offer is submitted.  Under no circumstances will BSCH
provide an amount greater than the equivalent in Euros of one billion
(1,000,000,000) U.S. Dollars, for any concept, nor will it subscribe more than
40% of the capital of Newco.  Likewise,
BSCH will not make any disbursement prior to the closing date, with the party
that in such case effectively makes the payment assuming all risks inherent to
said payment.  The rights inherent to the advance
payments of the price that are made prior to the Closing shall correspond to
the party that effectively makes said payment, for the purposes of the
contribution to Newco and the assessment, in the way that is legally deemed
most convenient, in accordance with the Rules of Procedure.  1.4The parties recognize that
notwithstanding section 1.2, if, in the opinion of Enel, the Rules of Procedure
do not allow the Establishment of Newco within the aforementioned time limit,
it would be necessary for each of the members of the Consortium to acquire the
shares of Elettrogen individually in proportion to their share capital.  In the case specified in the previous paragraph, the
parties, by mutual agreement, are required to negotiate the terms and
conditions under which said shares that are acquired individually and in
proportion to their share capital would then be transferred to Newco, generally
respecting the terms agreed upon herein.  2MAINTENANCE OF THE SHARE IN THE
SHARE CAPITAL OF NEWCO AND THE SYSTEM FOR THE TRANSFER OF SHARES  2.1Once the acquisition of shares
to which the previous Clause refers has been formalized, the parties agree to
maintain the stability of the shareholding in Elettrogen though Newco, under
the terms specified in the Italian Decree of November 8, 2000.  2.2In accordance with the previous
paragraph, Endesa shall not lose its condition as the strategic reference
shareholder through Newco, unless the application or interpretation of the
aforementioned Italian legislation is modified to reduce the specified time
period.  2.3BSCH, on its part:  i)By virtue of this document,
grants Endesa preferential acquisition rights to the shares of Newco or, in
such case, Elettrogen.  This right may
be exercised directly by Endesa or by any company freely designated by it.  ii)By virtue of this document,
irrevocably waives its right to subscription rights for any shares that may
eventually be issued as a result of the capital increase of Newco or Elettrogen,
in favor of Endesa or any company freely designated by it.  2.4The system of preferential
acquisition of shares by Endesa referred to in the preceding section shall be
applicable and shall take precedence over the statutory limitations that may,
in such case, be established in Newco.  For this purpose, and if necessary, the parties agree to
negotiate in good faith both the text of the aforementioned Articles of
Incorporation that will be proposed by Endesa, as well as, in such case, the
necessary modifications to this document or any other additional agreements
that may be required.  3 
   3SPECIAL SYSTEM FOR THE ADOPTION
OF RESOLUTIONS  3.1Notwithstanding the system of
majorities established in the Articles of Incorporation, the positive vote of
BSCH shall be required in order for the governing organs of Newco, as is
applicable in each case and in accordance with its articles of incorporation or
Italian law, to validly adopt the following resolutions:  I.Dissolution of the Company by
voluntary consent, as well as any merger or breakup other than the merger
carried out between Elettrogen and Newco  II.Disposal of a substantial part
of the corporate assets  3.2Notwithstanding the system that
may be established in the articles of incorporation and section 3.1, a majority
of more than 60% of the existing voting rights will be required for the Meeting
of the Shareholders of Newco to adopt any of the decisions that correspond to
it.  Likewise, and notwithstanding the system established in the
articles of incorporation and section 3.1, a majority of more than 2/3 of the
existing voting rights will be required in order for the Board of Directors or
other executive organs of Newco, as is applicable in accordance with its
articles of incorporation or Italian law, to adopt any of the decisions that
correspond to them.  3.3The parties agree that the
system of majorities referred to herein will be reviewed if one of the parties
acquires more than half of the share capital of Newco, establishing a system of
simple majorities, in accordance with Italian Law.  3.4The parties will make their best
efforts to ensure that any resolutions that may in such case be adopted by ASM
Brescia contain and respect the principles of qualification of majorities
referred to herein.  4ADMINISTRATION AND MANAGEMENT OF
THE COMPANY  4.1The participation of the Parties
in the Administrative organs of Newco will be proportional to their
participation in the share capital of the company.  4.2The Chairman of the
Administrative Organ and the Secretary of the Administrative Organ of
Elettrogen and Newco will be appointed by the Board and shall be proposed by
Endesa.  4.3The functional system,
frequency, and other rules of the administrative organ will be determined in
the articles of incorporation of Newco and Elettrogen, in accordance with
Italian Law in regard to this subject.  4.4The parties recognize Endesa as
the strategic reference shareholder of Elettrogen and Newco.  In accordance with this, the parties
recognize and accept that Elettrogen will execute the Industrial and Business
Plan that is attached to the Binding Offer prepared by Endesa, which may be
modified or developed.  The parties recognize the experience and capacity of Endesa
in the energy sector, specifically in the areas of energy production,
transport, distribution, commercialization, and management, which will be given
special consideration in the implementation of the plans and strategies
referred to in the previous paragraph, all without detriment to the
attributions and powers that may correspond to the Board of Directors of
Elettrogen.  For these purposes, Endesa may:  I.prepare and propose all
modifications and measures to develop or complement the aforementioned Industrial
and Business plan that it deems appropriate, with prior written notification
sent to BSCH  II.propose the General Manager of
the Company, who will be its head executive, on whom the rest of the members of
the Management Committee will depend.  The General Manager will be responsible for the ordinary
management of the Company, and must regularly inform the administrative organ
of any incidents that may occur in the Company.  In all cases, the General Manager will carry out the resolutions,
policies, and strategic criteria established by the Board of Directors.  4 
   5VALIDITY AND TERMINATION  5.1This Agreement shall be
terminated in the fullest legal sense in the following cases:  a.If the Consortium is not
selected in the procedure for the sale of 100% of the share capital of
Elettrogen, in accordance with the Rules of Procedure.  b.In all cases, if Enel has not
resolved the selection of the buyer of the shares of Elettrogen prior to
December 31, 2001.  c.By written agreement by both
parties.  d.If either party transfers all of
the shares held by it, terminating its condition as a shareholder in Newco.  e.Five years and six months
following the date on which this document is signed.  f.For failure to comply with the
obligations specified herein, notwithstanding the liabilities that may
correspond to the party that is in breach of the agreement.  This cause for termination may only be
invoked by the party that is not guilty of the default.  5.2In is agreed that termination of
this Agreement shall not affect the effectiveness of the obligations specified
in Clauses 6.7, 8, and 9.  6CONFIDENTIALITY OBLIGATIONS  6.1The parties agree that the
information that is revealed as a result of the preparation, negotiation, and
execution of this Agreement, and specifically in the establishment of Newco,
must be treated as confidential during the time in which it is in effect and
for a period of two years following its termination or severance, unless there is
an agreement in writing to the contrary.  Confidential information is understood to be any
technical, organizational, or commercial information provided or divulged in
any way by one of the Shareholders, including, as an example but no limited to,
information regarding: legal and technical specifications, specifications for
installations, strategies and/or services, industrial, strategic, commercial,
marketing organization, or business plans, financial information, statistical
information, or information on personnel.  6.2The confidentiality obligations
established in this clause shall not be applicable in regard to information
that:  a.Is provided by the Parties to
its advisers, lawyers, auditors, or consultants, who will, nevertheless be
informed of the confidential character of the information.  b.Is already possessed by, or has
been determined by other means by the party that receives it;  c.Is or becomes public;  d.Is required to be divulged by
legal order, mandate, process, or request by any governmental, legal or other
type of authority, especially stock exchange authorities.  7INDEMNIFICATION  The parties mutually agree to hold the other harmless for
any losses, bankruptcy, Lawsuits, or expenses that may be caused to one of the
parties as a result of its failure to comply with any commitment or obligation
in this document or that result from any false or incorrect representation or
guarantee.  8APPLICABLE LAW  The parties agree to subject this Agreement to Spanish
legislation, without detriment to any matters which, in such case, due legal
requirements, must be subject to Italian legislation.  5 
   9DISPUTE SETTLEMENT  9.1The parties agree that all
doubts or discrepancies regarding the application or interpretation of this
Agreement shall be settled, in good faith, by subjecting them to the joint
decision of the head executives, respectively, of both companies.  9.2If an agreement cannot be
reached by the means specified in the preceding paragraph, the parties agree
that the dispute will be settled through arbitration in law submitted to a Sole
Arbiter, the designation of whom, as well as the arbitration procedure, is
entrusted to the Civil and Mercantile Court of Arbitration (CIMA) of Madrid, in
accordance with its Bylaws.  The arbitration finding must be delivered within six (6)
months of the Arbiters acceptance of the appointment.  9.3The parties agree to comply
faithfully and promptly with the decision delivered in said arbitration.  10ADDRESSES FOR NOTICES  10.1All notices, communications,
declarations of intent, and other agreements related to or covered herein will
be sent by mail, fax, or any other written means, with acknowledgement by mail.  The following addresses are specified for the purposes of
sending notifications or communications to which this Agreement makes
reference:  ENDESA  To the attention of Antonio Redondo Cuesta  Address: Príncipe de Vergara 187  Madrid  Telephone: 91 213 00 00  BSCH  To the attention of Javier Laborda Fuerte  Address: Plaza de Canalejas, no. 1  Telephone: 91 558 11 11  10.2Each one of the parties shall be
responsible for notifying the other of changes of address or telephone or fax
numbers, with notifications sent to the addresses and numbers specified above
considered to be valid unless notice of their modification is sent.  11REPRESENTATIONS AND GUARANTEES  As a substantial part of this Agreement, the parties
represent and guarantee that:  i)They have full capacity and have
duly granted the necessary powers to submit the offer to which the Declarations
of this document refer, sign, and fulfill the conditions of this Agreement, as
well as the aforementioned offer and its stipulations in their specific terms,
and that once signed, the parties will be validly bound by them, and the
stipulations shall be fully applicable to them, without hindrance to the
recognition and execution of the resolutions of the judicial organs to which
they subject themselves by virtue of Clause Eleven of this Agreement.  ii)The signing of this Agreement
and the offer, and compliance with the obligations contained therein, do not
violate any of their articles of incorporation or any corporate resolution, nor
do they suppose a breach of any other agreement or contract with third parties,
or of any order, decree, or public or private regulation, or sentence of any
Court, Tribunal, or Public Administration organ to which the parties are
subject, or with respect to which they may be bound by virtue of the signing,
fulfillment, and execution of this Agreement. 
This representation shall be understood to be in effect and maintained
for the duration of the validity hereof.  6 
   12TRANSFER OF RIGHTS AND
OBLIGATIONS  The Rights and obligations to which this document refers
shall be freely transferred by Endesa to any of the companies wholly owned by
it with prior express authorization in this regard by BSCH, which may not be
rejected without justifiable cause.  13END  The Rights and obligations referred to herein are expressly
extended, and shall be applicable to any entity that in such case may succeed
Newco in the case of merger, dissolution, breakup, or any other similar
operations.  The parties expressly
recognize the possibility of the merger of Elettrogen and Newco for the
purposes of optimization of the project, and as a result of the application of
the stipulations contained herein to the resulting entity.  And, as proof of approval, the parties sign this document in
the place and on the date indicated above, in duplicate for a single purpose.  [Illegible signature]  ENDESA S.A.   [Illegible signature]  BANCO SANTANDER CENTRAL HISPANO, S.A.  7