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                                                                   EXHIBIT 10.20

                                HOLLY CORPORATION

                         SUPPLEMENTAL PAYMENT AGREEMENT
                          FOR 2002 SERVICE AS DIRECTOR

         This Supplemental Payment Agreement is entered into effective as of
December 13, 2001 between ______________ (the "Director") and Holly Corporation,
a Delaware corporation with its principal offices at 100 Crescent Court, Suite
1600, Dallas, Texas 75201 (the "Company").

         1. REASON FOR SUPPLEMENTAL PAYMENTS. As part of the compensation to the
Director for his services as a member of the Board of Directors of the Company
(the "Board") in the year ending with the Company's Annual Meeting of
Stockholders following the close of the Company's 2002 fiscal year, the Company
hereby agrees to pay deferred incentive compensation in the form of the payments
as provided in this Agreement.

         2. PHANTOM SHARES. Amounts payable under this Agreement ("Supplemental
Payments") shall be computed as if the Director had certain rights with respect
to 615.385 shares of the Company's Common Stock, par value $0.01 per share
("Common Stock"). For convenience, these shares are referred to herein as
"Phantom Shares." It is understood that the Phantom Shares are merely
bookkeeping entries used to compute Supplemental Payments to be paid to the
Director hereunder and do not constitute actual shares of Common Stock for any
purpose.

         3. ADJUSTMENTS IN NUMBER OF PHANTOM SHARES. In the event that there is
after December 13, 2001 any change in the Common Stock through merger,
consolidation, reorganization or recapitalization or in the event of any stock
split or dividend to holders of such stock payable in stock of the same class or
the issuance to such holders of rights to subscribe to stock of the same class,
or in the event of any change in the capital structure of the Company, the
number of Phantom Shares allocated to the Director immediately prior thereto
shall be adjusted so that the Director shall have allocated to him a number of
Phantom Shares that bears the same relation to the number of shares of Common
Stock (or shares into which shares of Common Stock are converted, as the case
may be) outstanding immediately after the happening of any such event as
immediately before the happening of such event.

         4. INTERIM PAYMENTS WITH RESPECT TO PHANTOM SHARE. So long as a final
payment pursuant to paragraph 5 ("Final Payment") has not been made with respect
to a Phantom Share, the Company shall pay to the Director from time to time with
respect to the Phantom Share an interim payment ("Interim Payment") equal to the
amount of the dividend in cash or property (but not shares of Common Stock) paid
per share to holders of shares of Common Stock. Each such Interim Payment shall
be paid at the same time as the payment of the dividend to which the Interim
Payment relates.

         5. FINAL PAYMENT WITH RESPECT TO PHANTOM SHARES. The Company shall make
a Final Payment with respect to the Phantom Shares in the amount determined
under paragraph 6 and at the time determined under paragraph 7. Upon the payment
of the Final Payment calculated as provided in paragraph 6 with respect to a
Phantom Share, the Phantom Share shall be treated as terminated for all purposes
and the Director and his successors in interest shall have no further rights of
any kind with respect to the Phantom Share.

         6. AMOUNT OF FINAL PAYMENT. The amount of the Final Payment with
respect to a Phantom Share shall equal the Applicable Value (as defined below)
of a share of Common Stock with respect to a date (the "Valuation Date") which
shall be either (a) the date that the Director ceases to serve as a member of
the Board for any reason other than resignation or (b) the date of the Company's
Annual Meeting of Stockholders that first occurs after the Director resigns as a
Director of the Company. The "Applicable Value" shall be the average, over the
20 trading days ending 5 trading days before the Valuation Date, of the daily
trading prices for shares of Common Stock as reported on the composite tape for
securities listed on the stock exchange on which the Common Stock is listed or
over the counter. However, if no sales of Common Stock were reported on said
composite tape for more than 3 days during the 20-trading-day period referred to
above, the Applicable Value shall be calculated using the average of the
reported trading prices on said composite tape for the most recent 7 trading
days before the Valuation Date on which trading in shares of Common Stock
occurred. In case there is more than one trading price on a day, the mean of the
high and low trading prices for the day shall be used as the daily trading price
for calculations under this paragraph.

         7. TIME FOR FINAL PAYMENT. The Final Payment with respect to all
Phantom Shares of the Director shall be made by check, in the amount per Phantom
Share determined under paragraph 6, within 40 days after the Valuation Date.

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         8. AUTHORITY OF BOARD TO ADMINISTER AND INTERPRET AGREEMENT. The Board
(or a committee designated by the Board) shall have complete authority to
construe, interpret and administer this Agreement. The determination,
interpretation and construction made by the Board or the committee designated by
the Board with respect to any aspect of this Agreement shall be final and
conclusive.

         9. RIGHT OF COMPANY TO MAKE FINAL PAYMENTS TO TERMINATE PHANTOM SHARES
IN CERTAIN CIRCUMSTANCES. Notwithstanding any other provision of this Agreement,
the Company shall have the right to terminate the Phantom Shares held by the
Director by making a Final Payment with respect to the remaining Phantom Shares
if (i) at any time the Board determines, in its reasonable judgment, that a
termination of the Phantom Shares is necessary or desirable in order for the
Company to comply appropriately with applicable government regulations or in
order to facilitate a transaction (other than simply the termination of the
Phantom Shares) that the Board determines to be in the best interest of the
Company or (ii) the Common Stock permanently ceases to be traded on a national
exchange or over the counter. The amount paid per Phantom Share pursuant to this
paragraph 9 shall be computed as provided in paragraph 6 using as the Valuation
Date the date of the Board determination (in the case of the circumstance listed
in (i) of the preceding sentence) or the date that trading in the Common Stock
permanently ceases (in the case of the circumstance listed in (ii) of the
preceding sentence). Any payment pursuant to this paragraph 9 shall be made
within 40 days after the Valuation Date determined in accord with the preceding
sentence.

         10. BENEFIT OF THE AGREEMENT. This Agreement shall be binding upon, and
inure to the benefit of and be enforceable by, the Director and the Director's
personal or legal representatives, executors, administrators, successors, heirs,
distributees, devisees, and legatees and the Company and its successors in
interest.

         11. RIGHTS NOT TRANSFERABLE. The interest of the Director or his
beneficiary under this Agreement is not subject to the claims of creditors and
may not be voluntarily or involuntarily sold, transferred, assigned, alienated
or encumbered.

         12. BENEFICIARIES; PAYMENTS TO INCOMPETENTS. If the Director dies
before receiving all amounts due hereunder, the unpaid amount shall be paid to
the beneficiary designated by the Director. No beneficiary designation shall be
valid unless it is in writing, signed by the Director, dated and filed with the
Company prior to death. Any beneficiary designation may be revoked and a new
designation may be made, as long as the new designation is in writing, signed by
the Director, dated and filed with the Company prior to death. If no beneficiary
has been designated under this Agreement, or there is no surviving designated
beneficiary or contingent beneficiary, any unpaid amounts will be paid to the
Director's estate as soon as administratively possible. Any amounts payable
hereunder to any person under legal disability or who, in the judgment of the
Board (or a committee designated by the Board), is unable to properly manage his
financial affairs may be paid to the legal representative of such person or may
be applied for the benefit of such person in any manner that the Board or the
committee designated by the Board may select.

         13. ENTIRE AGREEMENT. This Agreement constitutes and expresses the
whole agreement of the parties in reference to deferred compensation payments to
the Director for services as a member of the Board for the period ending with
the Company's Annual Meeting of Stockholders following the close of the
Company's 2002 fiscal year.

         14. AMENDMENTS. This Agreement may not be amended, modified, or
supplemented except by a writing signed by both of the parties hereto which
expressly refers to this paragraph 14.

         15. EFFECT OF INVALID TERM. If any term, provision, covenant, or remedy
of this Agreement or the application thereof to any person or circumstances
shall, to any extent, be construed to be invalid or unenforceable in whole or in
part, then such term, provision, covenant, or remedy shall be construed in a
manner so as to permit its enforceability under the applicable law and to
accomplish its intent to the fullest extent permitted by law. In any such case,
the remaining provisions of this Agreement, other than those which have been
held invalid or unenforceable, shall remain in full force and effect.

         16. AGREEMENT DOES NOT CREATE PROPERTY RIGHTS. Amounts payable under
this Agreement shall be unfunded. Any liability of the Company to the Director
with respect to this Agreement shall be based solely upon the contractual
obligations created by this Agreement and no such obligation of the Company
shall be deemed to be secured by any pledge or other encumbrance on any property
of the Company. Although accounts may be established with respect to the rights
of the Director under this Agreement, any such accounts shall be used merely as
a bookkeeping convenience. The Company shall not be required to segregate any
assets that may at any time be represented by cash, shares of Common Stock or
rights thereto, nor shall this Agreement be construed as providing for such
segregation, nor shall the Company be deemed to be a trustee of any cash, shares
of Common Stock or property under this Agreement. The Company shall not be
required at any time to provide any reports (other than as required for purposes
of income tax or securities law reporting purposes) or to give any security or
bond for the performance of any obligation that may be created by this
Agreement. Nothing contained

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in this Agreement, and no action taken pursuant to its provisions, shall create
or be construed to create a trust or a fiduciary relationship of any kind
between the Company and the Director or any other person. Neither the Director
nor any successor in interest shall acquire any interest in any assets of the
Company or in any investment reserves, accounts, or funds that the Company may
purchase, establish or accumulate for the purpose of paying benefits hereunder.

         17. NO RIGHTS TO CONTINUE TO SERVE AS DIRECTOR OR TO BE STOCKHOLDER.
The Director recognizes that this Agreement constitutes only an unsecured
promise by the Company to make future cash payments in certain circumstances and
that the Agreement confers no right for the Director to continue to serve as a
member of the Board or in any other capacity for the Company and confers no
rights as a stockholder in the Company.

         18. TAX MATTERS. The Company shall withhold any amounts from payments
made to the Director under this Agreement and deduct such amounts from income as
the Company determines to be necessary or desirable to ensure compliance with
applicable federal, state and local tax laws and to ensure that the Company may
properly deduct under applicable federal, state and local tax laws all amounts
paid pursuant to this Agreement.

         19. RELATIONSHIP OF AGREEMENT TO OTHER PLANS. No amount payable
hereunder shall be deemed compensation to the Director for the purpose of
computing benefits to which the Director may be entitled under any other
compensation agreement or arrangement or any benefit plan or arrangement of the
Company.

         20. COOPERATION IN COMPLIANCE WITH LEGAL REQUIREMENTS. The Company and
the Director each agree to file such reports with applicable governmental
authorities and to supply such information to the other party as may be
reasonably necessary to comply with or obtain the benefit of government
regulations that may apply to or with respect to the rights of and payments to
the Director under this Agreement.

         21. EFFECT OF HEADINGS. The paragraph headings of this Agreement are
not part of this Agreement and shall have no effect upon its construction or
interpretation.

         22. TEXAS LAW APPLICABLE. THIS AGREEMENT SHALL BE DEEMED TO BE MADE
UNDER AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS.

         IN WITNESS WHEREOF, the parties have signed and sealed this Agreement
as of the 13th day of December 2001.

                                      HOLLY CORPORATION

                                      By
                                        --------------------------------
                                        Matthew P. Clifton
                                        President

                                      [Name]
                                      Director

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                                                                   EXHIBIT 10.21

                           AMENDMENT NO. 5 AND CONSENT

AMENDMENT NO. 5 AND CONSENT dated as of May 6, 2002 (this AMENDMENT NO. 5)
between: HOLLY CORPORATION, NAVAJO REFINING COMPANY, L.P., BLACK EAGLE, INC.,
NAVAJO SOUTHERN, INC., NAVAJO NORTHERN, INC., LOREFCO, INC., NAVAJO CRUDE OIL
PURCHASING, INC., NAVAJO HOLDINGS, INC., HOLLY PETROLEUM, INC., NAVAJO PIPELINE
CO, L.P., LEA REFINING COMPANY, NAVAJO WESTERN ASPHALT COMPANY, and MONTANA
REFINING COMPANY, A PARTNERSHIP, as Borrowers and Guarantors, the BANKS listed
on the signature pages hereof, CANADIAN IMPERIAL BANK OF COMMERCE, as
Administrative Agent, CIBC INC. as Collateral Agent, FLEET NATIONAL BANK
(formerly known as Bank Boston Corp.), as Documentation Agent, GUARANTY BUSINESS
CREDIT CORPORATION, as Collateral Monitor, and CIBC WORLD MARKETS CORP, as Sole
Lead Arranger and Bookrunner.

WHEREAS

(A)      The parties hereto are party to an Amended and Restated Credit and
         Reimbursement Agreement dated as of April 14, 2000, as amended by
         Amendment No. 1 dated as of July 7, 2000, Amendment No. 2 dated as of
         April 4, 2001, Amendment No. 3 dated as of August 7, 2001 and Amendment
         No. 4 dated as of September 26, 2001 (as in effect on the date hereof,
         the CREDIT AGREEMENT), providing, subject to the terms and conditions
         thereof, for extensions of credit to be made by the Banks to the
         Borrowers in an aggregate principal or face amount not exceeding
         $100,000,000.

(B)      The Borrowers and the Guarantors wish to amend the Credit Agreement in
         order for Holly Corporation to be able to make certain additional
         Investments.

(C)      The Banks and Agents agree to amend the Credit Agreement in accordance
         with the provisions contained herein, and accordingly, the parties
         hereto hereby agree as follows:

DEFINITIONS

1. Except as otherwise defined in this Amendment No. 5, terms defined in the
Credit Agreement are used herein as defined therein.

AMENDMENTS

2. Subject to the satisfaction of the conditions precedent set forth in Section
4 below, the Credit Agreement shall be amended as follows effective on the date
hereof.

A.       Section 5.7 of the Credit Agreement is amended by:

         (i)      adding the following at the end of clause (b) thereof
                  ";provided (i) that such Unrestricted Subsidiary shall be
                  organized in a state of the United

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                  States and all or substantially all of the assets of such
                  Unrestricted Subsidiary shall be located in the United States
                  (a DOMESTIC INVESTMENT) and (ii) that the aggregate of all
                  such Investments and the Investments specified in clause (f)
                  below shall not exceed $50,000,000";

         (ii)     adding "(i)" at the beginning of clause (c) thereof and adding
                  the following at the end of clause (c) thereof ";provided that
                  for the purposes of this Section 5.7 only, First Tier Cash
                  Equivalents, Second Tier Cash Equivalents and Third Tier Cash
                  Equivalents need not be included in the Borrowing Base (and
                  shall not be included in the Borrowing Base unless the Secured
                  Party has a perfected, first priority security interest
                  therein) or subject to a perfected first priority security
                  interest of the Secured Party in order to qualify as permitted
                  Investments hereunder and (ii) Investments in instruments
                  rated not less than "A-" or better by Standard & Poor's Rating
                  Services or "A3" or better by Moody's Investor Service, Inc.,
                  that mature within five years of the date of acquisition by or
                  on behalf of the Company or any Subsidiary; provided that the
                  Investments described in this clause (ii),

                  (a)      together with the Investments described in clause (i)
                           above, shall have, taken as a whole, a maximum
                           average duration of not greater than 1 year;

                  (b)      shall be denominated solely in U.S. Dollars;

                  (c)      other than marketable direct or guaranteed
                           obligations of the United States of America or any
                           agency thereof, together with the Investments
                           described in clause (i) above, shall not in the
                           aggregate consist of more than 10% of such
                           Investments in any one obligor and not more than 7%
                           of such Investments in any single issuance from any
                           obligor;

                  (d)      together with the Investments described in clause (i)
                           above, shall have, taken as a whole, no single
                           industry constituting greater than 25% of such
                           Investments; and

                  (e)      together with the Investments described in clause (i)
                           above, shall have not more than 20% of the
                           Investments, taken as a whole, be "asset-backed" or
                           similar securities (and no more than 2% of such
                           Investments shall be in any single issue of such
                           asset-backed securities);"

         (iii)    deleting the reference to "$25,000,000" in clause (f) thereof
                  and replacing such reference with "$50,000,000"; and

                                                                          Page 2

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         (iv)     adding the following at the end of clause (f) thereof";
                  provided, further (x) such Refinery Investment shall be a
                  Domestic Investment and (y) that the aggregate of all such
                  Investments and the Investments specified in clause (b) above
                  shall not exceed $50,000,000".

B.       Section 5.15 of the Credit Agreement is amended by deleting the phrase,
         "and Restricted Investments made or acquired" in clause (ii) of the
         first sentence thereof.

REPRESENTATIONS AND WARRANTIES

3. Each of the Borrowers and the Guarantors represents and warrants to the Banks
and the Agents that (unless specifically limited to an earlier date) the
representations and warranties set forth in Section 4 of the Credit Agreement
are true and complete on and as of the date hereof with the same force and
effect as if made on and as of such date, and as if each reference in said
Section 4 to "this Agreement" included reference to this Amendment No. 5.

CONDITIONS PRECEDENT

4. As provided in Section 2, the amendments to the Credit Agreement set forth in
said Section 2 shall become effective, as of the date hereof, upon (i) the
receipt of the Administrative Agent of this Amendment No. 5, executed by each
Borrower and Guarantor, each Agent and the Required Banks and (ii) the filing of
such financing statements in the State of Delaware (and any other jurisdictions
required to maintain the perfection and priority of the Secured Party's Lien on
the assets of such entities) to reflect the conversion of each of Navajo
Refining Company, L.P. and Navajo Pipeline Co., L.P. from a corporation to a
limited partnership.

ACKNOWLEDGEMENT OF OBLIGORS

5. Each Obligor hereby (a) agrees that each reference to the Credit Agreement
and words of similar import in each Financing Document to which such Obligor is
party shall be a reference to the Credit Agreement as amended by this Amendment
No. 5 and (b) confirms that its obligations under each Financing Document to
which it is party remain in full force and effect after giving effect to the
amendment of the Credit Agreement by this Amendment No. 5.

MISCELLANEOUS

6. Except as herein provided, the Credit Agreement shall remain unchanged and in
full force and effect. This Amendment No. 5 may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
amendatory instrument and any of the parties hereto may execute this Amendment
No. 5 by signing any such counterpart. This Amendment No. 5 shall be governed
by, and construed in accordance with, the law of the State of New York.

                                                                          Page 3

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 5 to be
duly executed and delivered as of the day and year first above written.

HOLLY CORPORATION

By:    /s/ Stephen J. McDonnell
       ------------------------------------------
Title: Vice President and Chief Financial Officer

NAVAJO REFINING COMPANY, L.P.
BLACK EAGLE, INC.
NAVAJO SOUTHERN, INC.
NAVAJO NORTHERN, INC.
LOREFCO, INC.
NAVAJO CRUDE OIL PURCHASING, INC.
NAVAJO HOLDINGS, INC.
HOLLY PETROLEUM, INC.
NAVAJO PIPELINE CO., L.P.
LEA REFINING COMPANY
NAVAJO WESTERN ASPHALT COMPANY

By:    /s/ Stephen J. McDonnell
       ------------------------------------------
Title: Vice President and Chief Financial Officer

MONTANA REFINING COMPANY, A PARTNERSHIP

By Navajo Northern, Inc., its General Partner

By:    /s/ Stephen J. McDonnell
       ------------------------------------------
Title: Vice President and Chief Financial Officer

                                                                          Page 4

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CANADIAN IMPERIAL BANK OF COMMERCE, as Administrative Agent

By:    /s/ George Knight
       -------------------------
Title: Authorized Signatory

                                                                          Page 5

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CIBC INC., as Collateral Agent,

By:    /s/ George Knight
       -------------------------
Title: Authorized Signatory

                                                                          Page 6

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FLEET NATIONAL BANK, as Documentation Agent

By:    /s/ Christopher C. Holmgren
       -----------------------------
Title: Managing Director

                                                                          Page 7

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GUARANTY BUSINESS CREDIT CORPORATION, as Collateral Monitor

By:    /s/ James E. Casper
       -------------------------
Title: Senior Vice President

                                                                          Page 8

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CIBC WORLD MARKETS CORP., as Sole Lead Arranger and Bookrunner

By:    /s/ George Knight
       -------------------------
Title: Authorized Signatory

                                                                          Page 9

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BANKS

CANADIAN IMPERIAL BANK OF COMMERCE

By:    /s/ George Knight
       ----------------------------
Title: Authorized Signatory

                                                                         Page 10

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FLEET NATIONAL BANK

By:    /s/ Christopher C. Holmgren
       ------------------------------
Title: Managing Director

                                                                         Page 11

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GUARANTY BUSINESS CREDIT CORPORATION

By:    /s/ James E. Casper
       -------------------------
Title: Senior Vice President

                                                                         Page 12

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THE BANK OF NOVA SCOTIA

By:    /s/ N. Bell
       -------------------------
Title: Senior Manager

                                                                         Page 13

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PNC BUSINESS CREDIT

By:    /s/ Doug Clark
       -------------------------
Title: Vice President

                                                                         Page 14

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HIBERNIA NATIONAL BANK

By:    /s/ Nancy G. Moragas
       -------------------------
Title: Vice President

                                                                         Page 15

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