Document:

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                                                                     Exhibit 4.4

                                FOURTH AMENDMENT
                                       TO
                           REVOLVING CREDIT AGREEMENT

     This FOURTH AMENDMENT TO REVOLVING CREDIT AGREEMENT is made and entered
into as of September 26, 2001 (this "Amendment"), among (a) CALIFORNIA STEEL
                                     ---------
INDUSTRIES, INC., a Delaware corporation (the "Borrower"), (b) THE BANKS, (c)
                                               --------
BANK OF AMERICA, N.A., as loan and collateral agent for the Banks (in such
capacity, hereinafter the "Loan and Collateral Agent"), and (d) BANK OF AMERICA,
                           -------------------------
N.A., as documentation and letter of credit agent for the Banks (in such
capacity, hereinafter the "Letter of Credit Agent"). Capitalized terms used but
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not defined in this Amendment shall have the same meanings to such terms in the
Credit Agreement defined below.

     WHEREAS, the Borrower, the Banks, the Loan and Collateral Agent, the Letter
of Credit Agent and the Arrangers have entered into that certain Revolving
Credit Agreement, dated as of March 10, 1999 (as amended, restated, supplemented
or otherwise modified and in effect from time to time, the "Credit Agreement")
                                                            ----------------
pursuant to which the Banks have extended credit to the Borrower on the terms
set forth therein;

     WHEREAS, the Borrower has requested that the Banks amend the Credit
Agreement upon the terms and subject to the conditions contained herein; and

     WHEREAS, the Banks have agreed to amend the Credit Agreement upon the terms
and subject to the conditions contained herein;

     NOW, THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties agree as follows:

     1.   Amendment to the Credit Agreement. Subject to satisfaction of each of
          ---------------------------------
the conditions set forth in ss.3 below and effective as of the Effective Date,
the Borrower, the Loan and Collateral Agent, the Letter of Credit Agent and the
Banks hereby agree to amend ss.10.5 of the Credit Agreement by deleting the
amount "$34,000,000" contained in clause (c) of such ss.10.5 and substituting in
lieu thereof the amount "$26,000,000".

     2.   Representation and Warranties. The Borrower hereby represents and
          -----------------------------
warrants to each of the Banks, the Loan and Collateral Agent and the Letter of
Credit Agent as follows:

          (a)  Representations and Warranties in Credit Agreement. Each of the
               --------------------------------------------------
     representations and warranties of the Borrower contained in the Credit
     Agreement, the other Loan Documents or in any document or instrument
     delivered pursuant to or in connection with the Credit

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                                       -2-

     Agreement (i) were true and correct when made and (ii) after giving effect
     to this Amendment, continue to be true and correct on the date hereof
     (except to the extent of changes resulting from transactions contemplated
     or permitted by the Credit Agreement and the other Loan Documents, as
     amended hereby, and changes occurring in the ordinary course of business
     that singly or in the aggregate are not materially adverse, and to the
     extent that such representations and warranties relate expressly to an
     earlier date).

          (b)  Authority. The execution and delivery by the Borrower of the
               ---------
     Amendment and the performance by the Borrower of its agreements and
     obligations under the Amendment (i) are within its corporate authority (ii)
     have been duly authorized by all necessary proceedings, (iii) do not and
     will not conflict with or result in any breach or contravention or any
     provision of law, statute, rule or regulation to which the Borrower is
     subject or any judgment, order, writ, injunction, license or permit
     applicable to the Borrower so as to materially adversely affect the assets,
     business or any activity of the Borrower, (iv) do not conflict with any
     provision of the corporate charter or bylaws of the Borrower or any
     agreement or other instrument binding upon them, (v) require any waivers,
     consents or approvals by any of its creditors which have not been obtained,
     or (vi) require any approval which has not been obtained.

          (c)  Enforceability of Obligations. The Amendment and the Credit
               -----------------------------
     Agreement, as amended hereby, constitute the legal, valid and binding
     obligations of the Borrower enforceable against the Borrower in accordance
     with their respective terms, except as enforceability is limited by
     bankruptcy, insolvency, reorganization, moratorium or other laws relating
     to or affecting generally the enforcement of creditors' rights and except
     to the extent that availability of the remedy of specific performance or
     injunctive relief is subject to the discretion of the court before which
     any proceeding therefor may be brought.

     3.   Condition to Effectiveness. This Amendment shall become effective as
          --------------------------
of the date hereof subject to satisfaction of each of the following conditions
precedent (the "Effective Date"):
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          (a)  Execution and Delivery of Amendment. This Amendment shall have
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     been executed and delivered to the Loan and Collateral Agent by each of the
     Borrower, the Majority Banks and the Agents.

          (b)  Amendment Fee. The Borrower shall have paid to the Loan and
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     Collateral Agent a non-refundable amendment fee in an amount equal to
     $40,000 to be distributed equally among the Banks.

     4.   Affirmation and Acknowledgment of the Borrower. The Borrower hereby
          ----------------------------------------------
ratifies and confirms all of its Obligations to the Banks and the

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                                       -3-

Borrower hereby affirms its absolute and unconditional promise to pay to the
Banks the Revolving Credit Loans and all other amounts due under the Credit
Agreement, as amended hereby.

     5.   Miscellaneous Provisions. From and after the date hereof, this
          ------------------------
Amendment shall be deemed a Loan Document for all purposes of the Credit
Agreement and the other Loan Documents and each reference to Loan Documents in
the Credit Agreement and the other Loan Documents shall be deemed to include
this Amendment. Any breach by the Borrower of the covenants and obligations of
the Borrower contained herein shall be an immediate Event of Default. Except as
expressly provided herein, this Amendment shall not, by implication or
otherwise, limit, impair, constitute a waiver of or otherwise affect any rights
or remedies of the Loan and Collateral Agent or the Banks under the Credit
Agreement or the other Loan Documents, nor alter, modify, amend or in any way
affect any of the obligations or covenants contained in the Credit Agreement or
any of the other Loan Documents, all of which are ratified and confirmed in all
respects and shall continue in full force and effect. This Amendment may be
executed in any number of counterparts, but all of such counterparts shall
together constitute but one and the same agreement. Delivery of an executed
counterpart of a signature page by facsimile transmission shall be effective as
delivery of a manually executed counterpart of this Amendment. In making proof
of this Amendment, it shall not be necessary to produce or account for more than
one such counterpart.

     6.   Applicable Law. THIS AMENDMENT IS INTENDED TO TAKE EFFECT AS AN
          --------------
AGREEMENT UNDER SEAL AND SHALL BE CONSTRUED ACCORDING TO AND GOVERNED BY THE
LAWS OF THE STATE OF NEW YORK.

                  [remainder of page intentionally left blank]

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                                       -4-

     IN WITNESS WHEREOF, the undersigned have duly executed this Amendment as a
sealed instrument as of the date first set forth above.

                                             CALIFORNIA STEEL INDUSTRIES, INC.

                                             By: _______________________________
                                                 Name:  C. Lourenco Goncalves
                                                 Title: President and C.E.O.

                                             BANK OF AMERICA, N.A., as Loan and
                                              Collateral Agent

                                             By: _______________________________
                                                 Name:  Ken Puro
                                                 Title: Vice President

                                             BANK OF AMERICA, N.A., as a Bank
                                              and Letter of Credit Agent

                                             By: _______________________________
                                                 Name:  Jamie Harney
                                                 Title: Vice President

                                             WELLS FARGO BANK, N.A.

                                             By: _______________________________
                                                 Name:  Anthony D. Turner
                                                 Title: Vice President

                                             BANK OF TOKYO-MITSUBISHI, LTD.

                                             By: _______________________________
                                                 Name:  Takeo Sato
                                                 Title: Deputy General Manager

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                                       -5-

                                             THE INDUSTRIAL BANK OF JAPAN,
                                              LIMITED

                                             By: _______________________________
                                                 Name:  Yoshiaki Fujikawa
                                                 Title: SVP & Senior Manager<PAGE>

                                                                    Exhibit 10.1

                          [Digital Insight Letterhead]

September 24, 2001

Bruce Isaacson
28304 Foothill Drive
Agoura Hills, CA  91301

Dear Bruce:

I am very pleased to offer you a position with Digital Insight Corporation (the
"Company") as its Senior Vice President, Product Management, Marketing and
Alliances.  Your date of hire will be October 1, 2001.  In this capacity you
will report to Dale Walker, President and Chief Operating Officer.

You will be classified as an exempt, full time employee and receive an annual
salary of $200,000, which will be paid in accordance with the Company's normal
pay procedures.  Additionally, you will be eligible to participate in the
Company's executive management incentive Program with targeted cash bonus
compensation equal to 50% of your annual salary subject to the terms and
conditions of the Program.  The amount of the bonus award is subject to the sole
discretion of the Company Board of Directors, based upon performance targets for
you and/or the Company.  During 2001, your bonus will be guaranteed at twenty-
five thousand dollars ($25,000.00), to be paid in the first quarter of calendar
year 2002.  You will receive annual reviews for pay increases commensurate with
other senior executives of the Company, with due consideration to your
performance, Company performance, and other factors.

Subject to Board approval, you will be granted a stock option to purchase
175,000 shares of Digital Insight Common Stock.  The exercise price will be the
fair market value on your date of hire, which is equal to the Nasdaq closing
price of our stock on the previous trading day.  You will also receive future
stock option grants commensurate with other senior executives of the company.
The shares underlying the option will vest over a 48-month period with 25%
vesting 12 months after your date of hire and 1/48th of the total grant vesting
monthly thereafter.  The stock option is subject to the terms and conditions of
our stock option plan ("Option Plan") and will be documented separately by our
standard stock option agreement ("Option Agreement").  In the event of a "Change
in Control" of the Company, 50% of the remaining unvested shares underlying your
option and any future options granted by the Company as of that date will be
immediately vested.  As used in this offer, a "Change in Control" shall mean any
of the following transactions to which the Company is a party:

     (i)  a merger or consolidation in which the Company is not the surviving
          entity, except for (A) a transaction the principal purpose of which is
          to change the state of the Company's incorporation, or (B) a
          transaction in which the Company's stockholders immediately prior to
          such merger or consolidation hold (by virtue of securities received in
          exchange for their shares in the Company) securities of the surviving
          entity representing more than fifty percent (50%) of the total voting
          power of such entity immediately after such transaction;

     (ii) the sale, transfer or other disposition of all or substantially all of
          the assets of the Company unless the Company's stockholders
          immediately prior to such sale, transfer or other disposition hold (by
          virtue of securities received in exchange for their shares in the
          Company) securities of the purchaser or other transferee representing
          more than fifty percent (50%) of the total voting power of such entity
          immediately after such transaction; or

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     (iii)  any reverse merger in which the Company is the surviving entity but
            in which the Company's stockholders immediately prior to such merger
            do not hold (by virtue of their shares in the Company held
            immediately prior to such transaction) securities of the Company
            representing more than fifty percent (50%) of the total voting power
            of the Company immediately after such transaction.

You will be eligible to receive Company benefits enjoyed by all Digital Insight
employees and senior executives in accordance with the eligibility terms and
conditions of these programs. As an executive officer of the Company you will
exempt from the normal limits on paid time off that are defined in the Employee
Handbook, and the Company will not accrue paid time off for you. It is expected
that you will take paid time off as needed and at your discretion, subject only
to the approval of the President and Chief Operating Officer.  Participation in
the Company's AXIS.ABLE Flex Benefits program will be effective the 1st of the
month following 30 days of employment. These programs will be reviewed with you
in detail during your new hire orientation.

As a condition of your employment with Digital Insight, you will be required to
sign an employee Nondisclosure Agreement which requires, among other provisions,
the assignment of patent and other intellectual property rights to any invention
made during your employment at the Company and non-disclosure of proprietary
information. You agree that, during the term of your employment with the
Company, you will not engage in any other employment, occupation, consulting or
other business activity directly related to the business in which the Company is
now involved or becomes involved during the term of your employment, nor will
you engage in any other activities that conflict with your obligations to the
Company.  As an employee of the Company, you will also be expected to abide by
other Company rules, regulations and policies and acknowledge in writing that
you have read the Company's Employee Handbook (once it has been made available
to you).  Employment is also conditioned upon satisfactory results on a
background investigation. The background investigation will include the
following checks: 5 years employment verification, criminal background,
department of motor vehicles driving record, education verification and a credit
report.

For purposes of federal immigration law, you will be required to provide proof
of eligibility to work in the United States. Such documentation must be provided
to us within three (3) business days of your date of hire, or our employment
relationship with you may be terminated.  You shall be indemnified by the
Company against liability as an officer of the Company and any affiliate to the
maximum extent permitted by applicable law and Company by-laws.  This
indemnification shall continue so long as you may be subject to such liability.

For clarification and the protection of both you and the Company, this letter
and the agreement relating to proprietary rights between you and the Company,
set forth the terms of your employment with the Company and represents the sole
agreement between you and Digital Insight. It constitutes and expresses the
entire agreement regarding your employment. Any previous promises,
representations or understanding relative to any terms and conditions are not to
be considered as part of this offer unless expressed here in writing.  In the
event of any material inconsistency between the terms and provisions of this
letter and those of any currently existing Option Agreement, Option Plan, or
current written policy as documented in the Employee Handbook applicable to you,
your rights and/or the Company's obligations shall be established by the terms
and provisions of such letter, Option Agreement, Option Plan, or written policy,
which would be most beneficial to you.  The Option Agreement, Option Plan, and
Employee Handbook constitute all material plans, policies, and practices of the
company.    It is understood that employment is at the mutual consent of the
employee and the Company.  Accordingly, either the employee or the Company can
terminate the employment relationship at will, at any time, with or without
cause or advance notice, and without further obligation except as defined in
this letter and other documents referenced in this letter.

If your employment with the Company is terminated without Cause after three
months but before twelve months of employment, the Company will provide salary
and benefits continuation for a period of nine (9) months following the
termination date, ending no earlier than the one year anniversary of your date
of hire.  Also, immediately upon the termination date, the number of unvested
options that would have vested according to the vesting schedule reflected in
each respective option grant during the nine (9) month period following the

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termination date shall vest immediately.  All vested options shall be
exercisable for a period of three (3) months after such termination.

For purposes of the foregoing provisions of this letter, the term "Cause" shall
mean: (i) the conviction of any felony or any crime involving moral turpitude or
dishonesty; (ii) participation in a fraud or act of dishonesty against the
Company which adversely affects the Company in a material way; (iii) willful
breach of the Company's rules, regulations and policies which adversely affects
the Company in a material and demonstrable way; (iv) intentionally causing
material damage to the Company's property or business; (v) conduct which
constitutes gross insubordination; or (vi) habitual gross neglect of duties;
provided that the action or conduct described in clauses (iii), (v) and (vi)
above will constitute "Cause" only if such action or conduct continues after the
Company has provided Employee with written notice thereof and a reasonable
opportunity (to be not less than 30 days nor more than 90 days) to cure the
same.  For the above purposes, a termination by the Company without Cause
includes a termination of employment by you within 60 days following notice to
you of: (a) the assignment by the Company of any duties to you which are
inconsistent with, or reflecting a materially adverse change in, your position,
duties, responsibilities, reporting relationships, base salary, compensation, or
status with the Company,  (b) any required relocation greater than 50 miles from
the Company's home office in Calabasas, or (c) any material breach of this
letter agreement by the Company.

This letter may not be modified or amended except by a written agreement, signed
either by (a) you and the President and Chief Operating Officer of the Company,
or (b) you and the Chief Executive Officer of the Company.

To accept this offer, please sign and date this letter in the space provided
below and return it to me.

As you know Digital Insight is a growing Company with a bright future.  I am
delighted to extend this offer to you, and look forward to working with you at
Digital Insight.

Best regards,                            Acceptance:

/s/ Dawn M. Batey
-----------------
Dawn M. Batey                            /s/ Bruce Isaacson
Vice President Human Resources           ------------------

                                         Date:  September 24, 2001
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