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                                                                   EXHIBIT 10.23

                                                                 AUGUST 30, 1996


                            MAXUS ENERGY CORPORATION
                         STOCK APPRECIATION RIGHTS PLAN
                                    "PROBAC"


1.   ESTABLISHMENT AND PURPOSE

1.1  Establishment of the PLAN:
     ------------------------- 

     Maxus Energy Corporation ("Maxus" or the "Company") has established this
     Stock Appreciation Rights Plan for selected officers and EMPLOYEES of the
     Company ("PROBAC").  The terms and provisions applicable thereto are listed
     hereinbelow.

1.2  Purpose:
     ------- 

     The PROBAC is intended to promote the interests of Maxus and its
     shareholders, by giving its top executive officers and other key EMPLOYEES,
     an incentive in the long term to work toward the continued growth and
     success of Maxus though the grants of stock appreciation rights ("SARs")
     with respect to YPF Sociedad Anonima's, the owner of all or substantially
     all of Maxus' common stock ("YPF"), common shares of stock.  The Maxus
     Board of Directors also contemplates that the grants of SARs under the
     PROBAC will enhance Maxus' ability to attract and retain the highly skilled
     individuals necessary for its continued growth and success.

2.   DEFINITIONS

     Whenever used fully capitalized herein, the following terms shall have the
     specific meanings set forth below.  The singular shall include the plural
     and vice versa whenever the context shall so require, and references to the
     masculine gender are for convenience and shall include the feminine gender.

     BOARD shall mean Maxus' Board of Directors.

     BONUS GUIDELINES shall mean the rules and figures included in the
     COMMUNICATION LETTER that enable the calculation of the AWARD granted to
     the PARTICIPANT under the PROBAC in the referenced PLAN YEAR and include
     the GRANT DATE, the number of SARs granted and the INITIAL VALUE.

     CAUSE shall mean the PARTICIPANT's willful misconduct or gross negligence
     which is materially and demonstrably injurious to Maxus.

     COMMITTEE shall mean the Compensation Committee of the BOARD.
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     COMMUNICATION LETTER shall mean the letter whereby the PARTICIPANT is
     informed about his participation in the PLAN in a given PLAN YEAR and
     wherein the BONUS GUIDELINES applicable thereto are set.

     DISABILITY shall mean a mental or physical disability of a PARTICIPANT,
     which is (i) permanent, and (ii) total or serious enough so as to prevent
     the PARTICIPANT from performing his material duties (with or without
     reasonable accommodation) as determined by a physician designated by Maxus.

     EMPLOYEE shall mean any person working full time for Maxus not on an
     independent contractor basis.

     EXERCISE DATE shall mean the occasion on which, according to this PLAN, the
     economic worth of a SAR previously granted to a PARTICIPANT is defined and
     the said SAR is extinguished.

     EXERCISE VALUE shall mean, with respect to a specific SAR, one SHARE's
     average closing price for the last ten business days prior to the EXERCISE
     DATE of such SAR during which the SHARE was listed.

     GRANT shall mean the occasion upon which a SAR is granted to a PARTICIPANT.

     GRANT DATE shall mean the grant date specified in the COMMUNICATION LETTER.

     INITIAL VALUE shall mean, with respect to a specific SAR, one SHARE's
     average closing price for the last ten business days prior to the GRANT
     DATE of such SAR during which the SHARE was listed.  In cases of the
     EXERCISE VALUE and the INITIAL VALUE the value shall be made with reference
     to the closing prices published in the New York Stock Exchange Composite
     Report, failing which, it shall be made according to the same data
     published in another specialized publication.

     PARTICIPANT shall mean upon his participation in the PROBAC in a given PLAN
     YEAR, those officers and EMPLOYEES of Maxus selected by the President to
     receive GRANTS of SARs under the PLAN.

     PLAN shall mean this PROBAC, including any amendments thereto.

     PLAN YEAR shall mean a calendar year under the PROBAC beginning on or after
     January 1, 1996.  (It is understood that the first PLAN YEAR will be a
     partial calendar year which begins on the date this PLAN is established and
     ends on December 31, 1996.)

     PRESIDENT shall mean the President and Chief Executive Officer of Maxus.
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     RETIREMENT shall mean the TERMINATION OF EMPLOYMENT (when no CAUSE exists)
     decided by the PARTICIPANT (i) on or after reaching the age of 62, or (ii)
     between the age of 55 and 62, with the consent of the BOARD.

     SAR shall mean each of the stock appreciation rights granted to a
     PARTICIPANT under the PROBAC.

     SHARES shall mean YPF's Class "D" shares, par value of $10 pesos each.

     SPREAD shall mean any excess, if any of (i) the EXERCISE VALUE
     corresponding to the exercised SAR over (ii) the INITIAL VALUE
     corresponding to said SAR, except when the SPREAD on any EXERCISE DATE
     shall exceed 100% of the INITIAL VALUE corresponding to the relevant SAR,
     in which case the SPREAD shall be deemed to equal 100% of the said INITIAL
     VALUE.

     TERMINATION FOR CAUSE shall mean the decision made by the competent
     corporate management authority, on the basis of the existence of CAUSE, to
     terminate the PARTICIPANT's employment at Maxus or its affiliates.

     TERMINATION OF EMPLOYMENT shall mean the PARTICIPANT's departure from his
     employment at Maxus, including its affiliates.

3.   PARTICIPATION

     Only the PRESIDENT, if approved by the BOARD or COMMITTEE, and such
     EMPLOYEES as are appointed by the PRESIDENT will be PARTICIPANTS under the
     PROBAC for that PLAN YEAR.  An EMPLOYEE's participation in the PROBAC in a
     given PLAN YEAR shall not entitle the EMPLOYEE to participate in the PROBAC
     in future PLAN YEARS nor to claim any other compensation whatsoever or
     other consequence for his exclusion.

4.   AWARD GRANTS

4.1  Procedure:
     ---------

     As soon as reasonably practicable before or after the beginning of each
     PLAN YEAR, the BOARD or COMMITTEE, in the case of the PRESIDENT, and the
     PRESIDENT, in the case of all other PARTICIPANTS, shall consider the SARs
     to be granted to PARTICIPANTS.  Should the GRANTS be decided, the
     PARTICIPANTS shall be informed of their respective GRANTS in a written
     communication signed by the PRESIDENT or other appropriate person.  The
     said COMMUNICATION LETTER shall embody the BONUS GUIDELINES corresponding
     to the PARTICIPANT and will be accompanied or preceded by a copy of the
     PLAN and/or a prospectus relating thereto.  In order to perfect the GRANT,
     the PARTICIPANT shall return an executed copy of the COMMUNICATION LETTER.

     To the extent as may be required by Maxus' By-Laws, GRANTS shall be subject
     to the approval of the BOARD or COMMITTEE.  Further, no PARTICIPANT shall
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     be entitled to any SARs that are required to be registered under U.S. or
     Argentine securities laws (or payments in respect of any such SARs) unless
     such SARs have been so registered.  Nothing in this PLAN shall require
     Maxus to register such SARs.

4.2  Description of the Benefit:
     -------------------------- 

     The benefit conferred under PROBAC is the right of a PARTICIPANT to receive
     from Maxus on each EXERCISE DATE an amount in cash equivalent to the
     SPREAD, if any, multiplied by the number of SARs granted to that
     PARTICIPANT deemed exercised on such occasion.

4.3  Terms and Conditions of the SARs:
     -------------------------------- 

     Subject to the provisions of Section 5 below, the SARs granted on a
     specific GRANT DATE shall be automatically exercised as follows:  (i)  on
     the third anniversary of that GRANT DATE, one-third of the SARs granted on
     said GRANT DATE shall be deemed automatically exercised and will be
     immediately paid in cash by Maxus to the PARTICIPANT, such one-third
     portion to be thereafter terminated, (ii) on the fourth anniversary of that
     GRANT DATE, one-third of the SARs granted on said GRANT DATE will be deemed
     automatically exercised and will be immediately paid in cash by Maxus to
     the PARTICIPANT, such one-third portion to be thereafter terminated, and
     (iii) on the fifth anniversary of that GRANT DATE, the remaining SARs
     granted on said GRANT DATE will be deemed automatically exercised and will
     be immediately paid in cash by Maxus to the PARTICIPANT, such remaining
     portion to be thereafter terminated.  Nothing in the PLAN is intended to or
     shall be construed to entitle any PARTICIPANT to any SHARES.  If the SPREAD
     as to any such SARs is not positive on such an anniversary, no payment
     shall be due with respect to the SARs deemed exercised on the applicable
     anniversary.

4.4  Forfeiture of SARs:
     ------------------ 

     If, at the date of automatic exercise of a SAR, according to Subsection
     4.3, 5.2 or 6.1, the applicable SPREAD is not positive, the applicable
     portion of said SAR shall be deemed to have been canceled and to have
     expired immediately prior to said date, there being no entitlement to nor
     payment in favor of the PARTICIPANT, nor any liability on the part of Maxus
     or any other party as concerns said PARTICIPANT, with respect to such
     canceled portion of said SARs.

5.   TERMINATION OF EMPLOYMENT

5.1  TERMINATION OF EMPLOYMENT due to DISABILITY, Death, RETIREMENT or
     -----------------------------------------------------------------
     Involuntary Termination:
     ----------------------- 

     In case of TERMINATION OF EMPLOYMENT (i) due to the PARTICIPANT's
     RETIREMENT, DISABILITY or death or (ii) by a decision made by Maxus'
     competent management authority, grounded on any reason other than CAUSE,
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     all SARs granted to the PARTICIPANT and not exercised at the date of such
     TERMINATION OF EMPLOYMENT shall be deemed automatically exercised and
     canceled in full and if the SPREAD is positive, will be immediately paid by
     Maxus to the PARTICIPANT.  If the SPREAD as to such SAR is not positive on
     said date, no payment shall be due with respect to such SAR.

5.2  Other Reasons for TERMINATION:
     ----------------------------- 

     Should the TERMINATION OF EMPLOYMENT occur as a consequence of TERMINATION
     FOR CAUSE or of a voluntary decision made by the PARTICIPANT, other than
     his RETIREMENT, DISABILITY or death and should the provisions of Subsection
     5.1 not apply, all SARs granted to the PARTICIPANT not yet exercised at the
     date of such TERMINATION OF EMPLOYMENT shall be forfeited as concerns the
     PARTICIPANT and will be rendered fully void upon such TERMINATION OF
     EMPLOYMENT, without payment to the PARTICIPANT.

6.   OTHER PROVISIONS

6.1  Plan Termination:
     ----------------

     The PROBAC shall continue in force until terminated by the BOARD.  All SARs
     granted but not exercised at the date of such termination shall be deemed
     automatically and fully exercised and canceled as of said date and if the
     SPREAD is positive, will be immediately paid by Maxus to the PARTICIPANT,
     and as to any such SAR for which the SPREAD is not positive on such date,
     no payment shall be due.

6.2  Plan Amendment:
     -------------- 

     The BOARD may, in its sole discretion, amend the PLAN in whole or in part
     at any time, except that no amendment may adversely alter the rights of the
     PARTICIPANTS with respect to the SARs granted but not yet exercised as of
     the date of such amendment.

6.3  Governing Law:
     ------------- 

     The PROBAC shall be construed in accordance with and governed by the laws
     of Texas.

6.4  Withholding Taxes:
     ----------------- 

     Maxus shall deduct from all payments under the PROBAC any withholding taxes
     and/or any other tax (including FICA) required by law to be withheld with
     respect to any such payments.

6.5  Removal:
     ------- 
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     No provision of this PROBAC shall interfere with, or limit in any way the
     right of Maxus to terminate with or without CAUSE the work relationship it
     has with any PARTICIPANT, or be construed to constitute a contract of
     employment with any PARTICIPANT or to employ a PARTICIPANT in any
     particular position or for any particular period.

6.6  Nontransferability :
     ------------------  

     No right or interest of any PARTICIPANT under a SAR or this PROBAC may be
     assigned or transferred, pledged or encumbered in any manner.  Any attempt
     to assign, transfer, pledge or encumber any such right or interest shall
     not be effective as to, enforceable against or recognized by Maxus.

6.7  Adjustment to SARs:
     ------------------ 

     In the event that at any time after the effective date of the PROBAC, the
     SHARES then outstanding are changed into or exchanged for a different
     number or kind of shares or other securities of YPF by reason of merger,
     consolidation, recapitalization, reorganization, reclassification, stock
     split, stock dividends, combination of shares, capital increase or
     reduction, change in the par value of the SHARES or the like, or if the
     market value per SHARE is subject to a technical adjustment as a result of
     such event or as a result of a dividend distribution or other distribution
     made with respect to the SHARES, the BOARD may make an appropriate and
     equitable adjustment in the number and/or INITIAL VALUE of all SARs
     outstanding in order to prevent the reduction or enlargement of a
     PARTICIPANT's benefits under a SAR as in effect immediately prior to such
     event.  All decisions of the BOARD concerning such adjustments, or the lack
     of them, shall be final and binding for all PARTICIPANTS, Maxus and all
     other interested parties.

7.   ADMINISTRATION OF THE PLAN

7.1  Administration and Interpretation:
     --------------------------------- 

     The PROBAC shall be administered by the BOARD.  Subject to the provisions
     of the PROBAC, the BOARD shall construe the PLAN and all GRANTS thereunder,
     shall draft any rules it may deem necesary for the proper administration
     thereof, shall make other determinations necessary or advisable for the
     administration of the PLAN and shall correct any defect or supply any
     omission and reconcile any inconsistency in the PLAN or in any right
     granted thereunder, in the manner and to the extent that the BOARD deems
     desirable to effectuate the PROBAC.  Any action taken or determination made
     pursuant to the PROBAC shall be final and conclusive on all parties.  A
     PARTICIPANT's acceptance of a grant of SARs and participation under the
     PROBAC shall imply his full acceptance of the PLAN and BONUS GUIDELINES, as
     well as his acknowledgment of the binding and conclusive nature of the
     determinations made by the BOARD.
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7.2  Acceptance of Corporate Action:
     ------------------------------ 

     A PARTICIPANT shall have no right, by the mere fact of this participation
     in the PROBAC, to object to YPF's or Maxus' balance sheet, nor to question
     or oppose any corporate action by YPF or Maxus, notwithstanding its effect,
     if any, on the EXERCISE VALUE or market value of the SHARES or other
     ensuing consequences.

7.3  No Claims:
     --------- 

     Without limiting Maxus' rights under Subjections 6.1 and 6.2 the
     termination or amendment of the PLAN shall give no right to any claim or
     compensaiton whatsoever on the part of any PARTICIPANT other than as
     specifically set forth herein or in a grant of a SAR.

7.4  References
     ----------

     All references to Sections or Subsections shall be deemed as references to
     Sections or Subsections here in unless otherwise expressly provided for.

7.5  Captions:
     -------- 

     All captions in this PLAN are used merely for illustrative purposes and
     shall not be taken into account in the construction thereof.