SECOND
AMENDMENT


TO


FOURTH AMENDED AND RESTATED
REVOLVING CREDIT AGREEMENT











This
Second Amendment to Fourth Amended and Restated Revolving Credit Agreement (this
“Amendment”),
dated as of November 18, 2009, is entered into by (1) FRONTIER OIL AND REFINING
COMPANY, a Delaware corporation (the “Borrower”),
(2) FRONTIER OIL CORPORATION, a Wyoming corporation (“FOC”), (3)
each of the financial institutions party to the Credit Agreement referred to
below (the “Lenders”)
and (4) UNION BANK, N.A. (formerly known as “Union Bank of California, N.A.”), a
national banking association, as administrative agent (the “Administrative
Agent”) for the Lenders.








Recitals





A.           The
Borrower, FOC, the Lenders, the Administrative Agent and BNP Paribas, a French
banking corporation, as syndication agent, are party to a Fourth Amended and
Restated Revolving Credit Agreement dated as of August 19, 2008, as amended by a
First Amendment to Fourth Amended and Restated Revolving Credit Agreement dated
as of December 15, 2008 (said Credit Agreement, as so amended, herein called the
“Credit
Agreement”). Terms defined in the Credit Agreement and not otherwise
defined herein have the same respective meanings when used herein, and the rules
of interpretation set forth in Section 1.3 of the Credit Agreement are
incorporated herein by reference.





B.           The
Borrower has requested that the Lenders amend certain covenants and definitions
in the Credit Agreement. Accordingly, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Borrower, FOC, the
Lenders and the Administrative Agent hereby agree as set forth
below.








SECTION
1.  Amendments to Credit
Agreement


. Subject
to satisfaction of the conditions precedent set forth in Section 2 of this
Amendment, the Borrower, FOC and the Lenders hereby agree that the Credit
Agreement is amended as set forth below.





(a)  The
definitions of “Pricing Level 1,” “Pricing Level 2” and “Pricing Level 3” in
Section 1.1 of the Credit Agreement are amended in full to read as
follows:





“‘Pricing Level
1’ means the Pricing Level that applies to each Advance (whether then
outstanding or thereafter made) on and after, to each Letter of Credit (whether
then outstanding or thereafter issued) on and after, and to each Commitment on
and after, the date of receipt by the Administrative Agent of a schedule of
computations referred to in Section 6.4(a) or (b) if the ratio of (a) the
difference between Consolidated Long-Term Debt and the aggregate amount, if any,
of Cash Equivalents held by FOC and its Subsidiaries in excess of the sum of the
smallest aggregate amount of Cash Equivalents needed to be held by FOC and its Subsidiaries in order
for FOC to comply with the covenant contained in Section 7.10, all as determined
on the last day of the fiscal quarter of FOC ended immediately before that date,
to (b) Consolidated EBITDA for the Calculation Period ended on the last day of
that fiscal quarter was less than 2.25:1.00, as demonstrated by that schedule;
provided, however, that (i) if
the information in any such schedule is incorrect and results in the payment of
lower interest or fees than should have been paid based on the correct
information, then the Borrower shall nevertheless be liable to the Lenders and
the Administrative Agent for the correct amounts of interest and fees and will
pay any unpaid portion of the same to the Administrative Agent for the benefit
of the Person(s) entitled thereto, promptly upon demand therefor, and (ii) if
FOC fails to deliver any such schedule by the required day, then Pricing Level 3
shall apply until FOC delivers such schedule and the appropriate Pricing Level
can be determined.”





“‘Pricing Level
2’ means the Pricing Level that applies to each Advance (whether then
outstanding or thereafter made) on and after, to each Letter of Credit (whether
then outstanding or thereafter issued) on and after, and to each Commitment on
and after, the date of receipt by the Administrative Agent of a schedule of
computations referred to in Section 6.4(a) or (b) if the ratio of (a) the
difference between Consolidated Long-Term Debt and the aggregate amount, if any,
of Cash Equivalents held by FOC and its Subsidiaries in excess of the sum of the
smallest aggregate amount of Cash Equivalents needed to be held by FOC and its Subsidiaries in order
for FOC to comply with the covenant contained in Section 7.10, all as determined
on the last day of the fiscal quarter of FOC ended immediately before that date,
to (b) Consolidated EBITDA for the Calculation Period ended on the last day of
that fiscal quarter was equal to or greater than 2.25:1.00 but less than
3.00:1.00, as demonstrated by that schedule; provided, however, that (i) if
the information in any such schedule is incorrect and results in the payment of
lower interest or fees than should have been paid based on the correct
information, then the Borrower shall nevertheless be liable to the Lenders and
the Administrative Agent for the correct amounts of interest and fees and will
pay any unpaid portion of the same to the Administrative Agent for the benefit
of the Person(s) entitled thereto, promptly upon demand therefor, and (ii) if
FOC fails to deliver any such schedule by the required day, then Pricing Level 3
shall apply until FOC delivers such schedule and the appropriate Pricing Level
can be determined.”





“‘Pricing Level
3’ means the Pricing Level that applies to each Advance (whether then
outstanding or thereafter made) on and after, to each Letter of Credit (whether
then outstanding or thereafter issued) on and after, and to each Commitment on
and after, the date of receipt by the Administrative Agent of a schedule of
computations referred to in Section 6.4(a) or (b) if the ratio of (a) the
difference between Consolidated Long-Term Debt and the aggregate amount, if any,
of Cash Equivalents held by FOC and its Subsidiaries in excess of the sum of the
smallest aggregate amount of Cash Equivalents needed to be held by FOC and its Subsidiaries in order
for FOC to comply with the covenant contained in Section 7.10, all as determined
on the last day of the fiscal quarter of FOC ended immediately before that date,
to (b) Consolidated EBITDA for the Calculation Period ended on the last day of
that fiscal quarter was equal to or greater than 3.00:1.00, as demonstrated by
that schedule; provided, however, that (i) if
the information in any such schedule is incorrect and results in the payment of
lower interest or fees than should have been paid based on the correct
information, then the Borrower shall nevertheless be liable to the Lenders and
the Administrative Agent for the correct amounts of interest and fees and will
pay any unpaid portion of the same to the Administrative Agent for the benefit
of the Person(s) entitled thereto, promptly upon demand therefor, and (ii) if
FOC fails to deliver any such schedule by the required day, then Pricing Level 3
shall apply until FOC delivers such schedule and the appropriate Pricing Level
can be determined.”





(b)  Section
7.10 of the Credit Agreement is amended in full to read as follows:





“Section
7.10                                Leverage Ratio. FOC
will not permit the ratio of (a) the difference between Consolidated Funded Debt
as of the last day of any fiscal quarter of FOC and the aggregate amount of Cash
Equivalents held by FOC and its
Subsidiaries as of the last day of such fiscal quarter to (b)
Consolidated EBITDA for the Calculation Period ended on the last day of such
fiscal quarter to be greater than 3.50 to 1.00, as measured by the financial
information to be delivered pursuant to Section 6.4(a) or (b).”





(c)  Section
7.13 of the Credit Agreement is amended in full to read as follows:





“Section
7.13                                Holding of Cash
Equivalents. FOC will not permit the aggregate amount of Cash Equivalents
held by it and its Subsidiaries at any and all times during any fiscal quarter
of FOC to be less than the sum of (a) the smallest aggregate amount of Cash
Equivalents needed to be held by FOC and its Subsidiaries as of the
end of the immediately preceding fiscal quarter of FOC in order for FOC to
comply with the covenant contained in Section 7.10 and (b) the smallest
additional aggregate amount of Cash Equivalents needed to be held by FOC and its
Subsidiaries (but not in excess of the additional aggregate amount of Cash
Equivalents actually held by FOC and its Subsidiaries) as of the end of such
fiscal quarter in order for the Borrower to qualify for the most favorable (to
it) Pricing Level.”





SECTION
2.  Conditions
Precedent


. This
Amendment shall become effective on the date, not later than December 31, 2009,
on which the Administrative Agent has received all of the following, each dated
the date hereof, in form and substance satisfactory to the Administrative Agent
and in the number of originals requested thereby:





(a)  this
Amendment, duly executed by the Borrower, FOC and the Majority Lenders;
and





(b)  a consent
to this Amendment, duly executed by the Guarantors and by the Borrower, in its
capacity as guarantor under the Borrower Guaranty.





SECTION
3.  Representations and
Warranties


. Each of
the Borrower and FOC represents and warrants to the Lenders and the
Administrative Agent as set forth below.





(a)  The
execution, delivery and performance by each of the Borrower and FOC of this
Amendment and the Credit Agreement, as amended hereby, and the consummation of
the transactions contemplated hereby and thereby, are within such Credit Party’s
legal powers, have been duly authorized by all necessary legal action and do not
(i) contravene such Credit Party’s charter documents or bylaws, (ii) violate any
Governmental Rule, (iii) conflict with or result in the breach of, or constitute
a default under, any Material Contract, loan agreement, indenture, mortgage,
deed of trust or lease, or any other contract or instrument, binding on or
affecting such Credit Party, any of its Subsidiaries or any of their respective
properties, the conflict, breach or default of which could reasonably be
expected to have a Material Adverse Effect, or (iv) result in or require the
creation or imposition of any Lien upon or with respect to any of the properties
of such Credit Party or any of its Subsidiaries, except for Liens created or
permitted under the Credit Documents, as amended hereby. Neither such Credit
Party nor any of its Subsidiaries is in violation of any Governmental Rule or in
breach of any such contract, loan agreement, indenture, mortgage, deed of trust,
lease or other contract or instrument, the violation or breach of which could
reasonably be expected to have a Material Adverse Effect.





(b)  No
Governmental Action, and no authorization, approval or other action by, or
notice to, any third party, is required for the due execution, delivery or
performance by the Borrower or FOC of this Amendment or the Credit Agreement, as
amended hereby, or for the consummation of the transactions contemplated hereby
or thereby, except for (i) authorizations, approvals and other actions by, and
notices to, third parties, the failure to obtain which could not reasonably be
expected to have a Material Adverse Effect, and (ii) Governmental Action that
has been duly obtained, taken, given or made and is in full force and
effect.





(c)  This
Amendment and the Credit Agreement, as amended hereby, have been duly executed
and delivered by the Borrower and FOC. This Amendment and the Credit Agreement,
as amended hereby, are the legal, valid and binding obligations of the Borrower
and FOC, enforceable against each such Credit Party in accordance with their
respective terms, except as the enforceability hereof or thereof may be limited
by bankruptcy, insolvency, moratorium, reorganization or other similar laws
affecting creditors’ rights generally or by equitable principles relating to
enforceability.





(d)  Each of
the Security Agreement and the Stock Pledge Agreement constitutes a valid and
perfected first-priority Lien on the Collateral purported to be encumbered
thereby, enforceable against all third parties in all jurisdictions, and secures
the payment of all obligations of the Borrower or FRMI, as applicable, under the
Credit Documents, as amended hereby, to which the Borrower or FRMI, as
applicable, is a party, and the execution, delivery and performance of this
Amendment do not adversely affect the Lien of the Security Agreement or the
Stock Pledge Agreement.





(e)  There has
been no amendment to the charter documents or bylaws of the Borrower or FOC on
or after August 19, 2008, except for the amendment and restatement of FOC’s
bylaws as provided in the Report on Form 8-K dated November 11, 2008 filed with
the Securities and Exchange Commission. The representations and warranties
contained in each Credit Document, as amended hereby, to which the Borrower
and/or FOC is a party are correct in all material respects on and as of the date
hereof, before and after giving effect to this Amendment, as though made on and
as of the date hereof. No event has occurred and is continuing, or would result
from the effectiveness of this Amendment, that constitutes a
Default.





SECTION
4.  Reference to and Effect on
Credit Documents


.





(a)  On and
after the effective date of this Amendment, each reference in the Credit
Agreement to “this Agreement,” “hereunder,” “hereof,” “herein” or words of like
import referring to the Credit Agreement, and each reference in the other Credit
Documents to “the Credit Agreement,” “thereunder,” “thereof,” “therein” or words
of like import referring to the Credit Agreement, shall mean and be a reference
to the Credit Agreement as amended by this Amendment.





(b)  Except as
specifically amended above, the Credit Agreement and the other Credit Documents
shall remain in full force and effect and are hereby ratified and confirmed.
Without limiting the generality of the foregoing, the Security Agreement and the
Stock Pledge Agreement and all of the Collateral described therein do and shall
continue to secure the payment of all obligations under the Credit Documents, as
amended hereby, stated to be secured thereby.





(c)  The
execution, delivery and effectiveness of this Amendment shall not operate as a
waiver of any right, power or remedy of the Administrative Agent or any Lender
under any of the Credit Documents or constitute a waiver of any provision of any
of the Credit Documents.





SECTION
5.  Costs and
Expenses


. The
Borrower agrees to pay on demand all costs and expenses of the Administrative
Agent in connection with the preparation, execution and delivery of this
Amendment and the other instruments and documents to be delivered hereunder,
including the reasonable fees and out-of-pocket expenses of counsel for the
Administrative Agent with respect thereto and with respect to advising the
Administrative Agent as to its rights and responsibilities hereunder and
thereunder.





SECTION
6.  Execution in
Counterparts


. This
Amendment may be executed in any number of counterparts and by the parties
hereto in separate counterparts, each of which when so executed and delivered
shall be deemed to be an original and all of which taken together shall
constitute one and the same agreement. Delivery of an executed counterpart of a
signature page to this Amendment by telecopier or e-mail shall be effective as
delivery of an originally executed counterpart of this Amendment.





SECTION
7.  Governing
Law


. THIS AMENDMENT SHALL BE GOVERNED BY,
AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
CALIFORNIA APPLICABLE TO CONTRACTS MADE AND PERFORMED IN THE STATE OF
CALIFORNIA.














[Signature
pages follow.]





The
parties hereto have caused this Amendment to be executed by their respective
duly authorized representatives as of the date first written above.








FRONTIER
OIL AND REFINING COMPANY








By:       /s/
Doug S.
Aron


Name:  Doug
S.
Aron


Title:    EVP
&
CFO











FRONTIER
OIL CORPORATION








By:       /s/
Doug S.
Aron


Name:  Doug
S.
Aron


Title:    EVP
&
CFO











UNION
BANK, N.A.,


as
Administrative Agent and Lender








By:       /s/ Randall
Osterberg


Name: Randall
Osterberg


Title:   Senior
Vice
President











BNP
PARIBAS








By:        /s/ Edward
Pak


Name:  Edward
Pak


Title:    Vice
President








By:        /s/ Russell
Otts


Name:   Russell
Otts


Title:     Director











TORONTO
DOMINION (TEXAS) LLC








By:       /s/ Jackie
Barrett


Name:  Jackie
Barrett


Title:    Authorized
Signatory











WELLS
FARGO BANK, N.A.








By:      
/s/ Suzanne
Bidenhour


Name:  Suzanne
Bidenhour


Title:    Vice
President











U.S. BANK
NATIONAL ASSOCIATION








By:       /s/ Monte E.
Deckerd


Name:  Monte
E.
Deckerd


Title:    Senior
Vice
President











EXPORT
DEVELOPMENT CANADA








By:       /s/ Shawn
Cusick


Name:  Shawn
Cusick


Title:    Loan
Portfolio
Manager








By:       /s/ Arturo
Polisena


Name: Arturo
Polisena


Title:   Asset
Manager








SUMITOMO
MITSUI BANKING CORPORATION








By:        /s/ William M.
Ginn


Name:  William
M.
Ginn


Title:    General
Manager











BANK OF
SCOTLAND PLC








By:       /s/ Julia R.
Franklin


Name:  Julia
R.
Franklin


Title:    Assistant Vice
President











CAPITAL
ONE, N.A.








By:       /s/ Wesley
Fontana


Name:  Wesley
Fontana


Title:    Assistant
Vice
President











UBS LOAN
FINANCE LLC








By:       /s/ Mary E.
Evans


Name:  Mary
E.
Evans


Title:    Associate
Director








By:       /s/ Irja R.
Otsa


Name:  Irja
R.
Otsa


Title:    Associate
Director











THE FROST
NATIONAL BANK








By:       /s/ Thomas H.
Dungan


Name: Thomas
H.
Dungan


Title:   Senior
Vice
President











NATIXIS








By:      /s/ Louis P.
Laville


Name: Louis
P.
Laville


Title:   Managing
Director








By:      /s/ Daniel
Payer


Name: Daniel
Payer


Title:   Director