Document:

<PAGE>

                                                                     EXHIBIT 4.5

                          DIRECTOR SHARE PURCHASE PLAN

                        FOR DIRECTORS OF NOVA CORPORATION

Effective May 10, 1994, NOVA Corporation assumed all rights and obligations of
NOVA Corporation of Alberta under the Director Share Purchase Plan for Directors
of NOVA Corporation of Alberta. NOVA Corporation of Alberta heretofore
established the said Director Share Purchase Plan effective as of January 1,
1994. Effective as of May 10, 1994 the said Director Share Purchase Plan is
amended and restated as hereinafter set forth as the Director Share Purchase
Plan for Directors of NOVA Corporation.

1.   DEFINITIONS

1.1  In this plan (including this Section) unless there is something in the
context inconsistent therewith, the following definitions shall have the
following meanings respectively:

     "ASSETS" means in respect of the Fund or a Member's Account the following
     property held under the Plan in respect of the Fund or such Member's
     Account:

          (a) the number of NOVA Common Shares held by the Custodian;

          (b) all securities, other assets and cash (the latter held pending
          investment in NOVA Common Shares) received by way of dividends or
          distributions on or in respect of NOVA Common Shares previously
          purchased and then held by the Custodian;

          (c) interest paid by the Custodian on cash deposits in a Member's
          Account; and

          (d) cash then held by the Custodian pending investment or disbursement
          upon a withdrawal permitted by Article 9 hereof;

     "ATTENDANCE FEES" means the amounts payable by the Corporation to a Member
     as remuneration for the Member's attendance at meetings of the Board of
     Directors or of a Committee of the Board of Directors;

     "BOARD OF DIRECTORS" means the board of directors of the Corporation;

     "COMMITTEE" means the committee appointed by the Corporation, pursuant to
     Article 10 hereof;

     "COMMITTEE OF THE BOARD OF DIRECTORS" means a committee comprised of
     Directors appointed by the Board of Directors pursuant to the By-laws of
     the Corporation;

     "CONTRIBUTIONS" means Director Fees, minus all Withholding Amounts,
     designated by a Director in a Notice submitted pursuant to Sections 3.1 and
     4.2 hereof;

<PAGE>
                                       2

     "CORPORATION" means NOVA Corporation, a corporation incorporated under the
     laws of the Province of Alberta and any successor or continuing corporation
     resulting from any form of corporate reorganization;

     "CUSTODIAN" means a person or company appointed to act as custodian of the
     Fund for the benefit of the Members and any permitted successor or assign
     thereof;

     "CUSTODIAN AGREEMENT" means the Custodianship and Agency Agreement between
     the Corporation and the Custodian which provides for the establishment of
     the Fund as may be amended from time to time pursuant to the terms thereof;

     "DRSPP" means the Dividend Reinvestment and Share Purchase Plan of the
     Corporation;

     "DIRECTOR" means a member of the Board of Directors;

     "DIRECTOR FEES" means Retainer Fees, Attendance Fees, Travel Fees and all
     other amounts that are payable by the Corporation to a Member as
     remuneration for services performed by the Member as a Director but does
     not include expenses for which a Director is entitled to be reimbursed;

     "EFFECTIVE DATE" means January 1, 1994;

     "FUND" means the aggregate of the Members' Accounts;

     "MEMBER" means any Director who becomes a participant under the Plan in
     accordance with Section 3.1 hereof and who has not ceased to be a Member as
     provided in Section 9.6 hereof;

     "MEMBER'S ACCOUNT" means all cash, NOVA Common Shares and other assets held
     by the Custodian on behalf of the Member under the Plan, including
     Contributions held pending investment or disbursement to a Member pursuant
     to Article 9 hereof and all securities, other assets and cash (the latter
     held pending investment in NOVA Common Shares) received by way of dividends
     or distributions whenever made on or in respect of NOVA Common Shares
     previously purchased and held in the Member's Account and any interest on
     any of the foregoing;

     "NOTICE" means a written notification submitted to the Corporation and to
     the Custodian on the forms prescribed by the Corporation;

     "NOVA COMMON SHARES" means issued and outstanding common shares in the
     share capital of the Corporation as constituted at May 10, 1994 or as
     subsequently consolidated or subdivided and any other shares resulting from
     redemption or change of such shares or resulting from amalgamation,
     consolidation, merger, plan, of arrangement, reorganization or otherwise;

<PAGE>
                                       3

     "PLAN" means the Director Share Purchase Plan for Directors of NOVA
     Corporation established by the Corporation and includes any subsequent
     amendments, modifications and supplements hereto;

     "RETAINER FEES" means the amounts payable by the Corporation to a Member as
     remuneration for services performed by the Member as a Director, other than
     Attendance Fees and Travel Fees;

     "TRAVEL FEES" means the amounts payable by the Corporation to a Member as
     remuneration for the Member's attendance at meetings of the Board of
     Directors or of a Committee of the Board of Directors;

     "WITHHOLDING AMOUNTS" means all amounts required to be withheld or deducted
     from Director Fees or dividends for or on account of any present or future
     taxes, duties, assessments, interest or charges imposed or levied by or on
     behalf of any government, governmental authority or agency having the power
     to tax and required by law or the administration thereof to be withheld or
     deducted;

     "THIS PLAN, HEREIN, HEREOF, HEREUNDER", and similar expressions refer to
     this Plan and not to any particular section or subsection, clause or
     subdivision or other portion hereof and includes any and every amendment,
     modification and supplement hereto.

2.   GENERAL

2.1  The Plan shall be effective commencing on and after the Effective Date.

2.2  Should any Member entitled to receive any benefits hereunder be, in the
judgment of the Custodian, physically or mentally incapable of personally
receiving and giving a receipt for any payment or distribution, the Custodian
may make payment or distribution into court or to such other person or persons,
if any, who are legally entitled to receive such payment or distribution, and
such payment or distribution shall constitute a complete discharge of all
liability with respect to any such benefit.

2.3  The Committee may from time to time prescribe such forms or other Notices
or communications for use by the Committee, the Custodian, the Corporation, the
Members and by Directors as the Committee may deem appropriate and may specify
the information to be included in such forms, Notices or other communications to
be given and the time within which such forms, Notices or communications shall
be given. The Committee may waive any such requirement on such terms and
conditions, if any, as the Committee may deem appropriate.

2.4  In the case of any withdrawal of all or a portion of a Member's Account the
delivery of certificates representing NOVA Common Shares and payment of any
amount in a Member's Account being withdrawn shall be made by the Custodian to
the person or persons entitled thereto within such reasonable time after the
date the Custodian is requested to make such delivery and payment as is required
for the due processing of such request and any sale of assets or securities
required in order to make such payment.

<PAGE>
                                       4

2.5  Notwithstanding any other provision of the Plan, the Custodian may not be
required to acquire for the purpose of the Plan any NOVA Common Shares which
will result in the Fund holding, in the aggregate, more than 10% of the
outstanding number of NOVA Common Shares.

3.   ELIGIBILITY AND REGISTRATION

3.1  Any person who is or becomes a Director shall be entitled to elect to
participate as a Member of the Plan by submitting a Notice to the Corporation
and the Custodian which designates the amount of Contributions such Member
elects to have the Corporation deposit with the Custodian into such Member's
Account which shall be equal to at least 50% of the amount of Retainer Fees
payable to such Member calculated after deduction of Withholding Amounts.

4.   CONTRIBUTIONS

4.1  Subject to the terms of the Plan, the Corporation shall pay to the Member's
Account at the end of each calendar quarter an amount equal to the Member's
Contributions designated by the Member in the Notice submitted pursuant to
Sections 3.1 and 4.2 hereof.

4.2  A Member shall be entitled, by submitting a Notice to the Corporation and
the Custodian on or prior to the 15th day of the month in which the end of a
calendar quarter occurs, to change the designated amount of such Member's
Contributions to be deposited by the Corporation with the Custodian in such
Member's Account, provided that the designated amount shall be equal to at least
50% of the amount of Retainer Fees payable to such Member calculated after
deduction of Withholding Amounts.

5.   INVESTMENT PROVISIONS

5.1  All Contributions payable by the Corporation to a Member shall be deposited
with the Custodian in the Member's Account for investment by the Custodian as
soon as reasonably practicable in NOVA Common Shares to be purchased by the
Custodian in the open market. All NOVA Common Shares purchased by the Custodian
for and on behalf of a Member shall be deposited and thereafter held in the
Member's Account subject to the provisions of Articles 6 and 9 hereof. Pending
investment, the Custodian shall pay interest on such contributions.

5.2  NOVA Common Shares purchased for a Member's Account shall be purchased in
the open market.

5.3  The Custodian shall, with respect to all whole and fractional NOVA Common
Shares held in the Fund, participate in the DRSPP. Any dividends or other cash
distributions on whole and fractional NOVA Common Shares shall, pursuant to and
in accordance with the DRSPP, be reinvested in NOVA Common Shares. Each Member,
by participating in the Plan, agrees to the Custodian's participation in the
DRSPP in respect of all whole and fractional NOVA Common Shares so acquired for
the Member.

5.4  The Custodian will credit the Member's Account with whole and fractions of
NOVA Common Shares. A Member will be credited with dividends on whole and
fractional NOVA Common Shares held in a Member's Account. In the case of a
withdrawal involving a fraction of

<PAGE>
                                       5

a NOVA Common Share, nothing in this Plan shall require the Custodian to sell,
purchase or deliver any fraction of a NOVA Common Share, provided that the
person entitled to the delivery of a fractional NOVA Common Share receives a
cash payment therefor based upon the closing price on The Toronto Stock Exchange
on the relevant date or if such date is not a day on which a closing price is
available, on the next immediately preceding day on which a closing price is
available. The Custodian will take up and purchase for its own account at the
price specified in this Section 5.4 any fraction of a NOVA Common Share
requested to be delivered to a Member or otherwise required to be sold where a
purchaser therefor cannot be found.

5.5  The Custodian shall, within two business days following the purchase of or
reinvestment in NOVA Common Shares pursuant to Section 5.1 or 5.3 hereof,
respectively, provide to a Member and to the Corporation a statement showing the
number of NOVA Common Shares purchased or reinvested on behalf of such Member,
the purchase price thereof and the cumulative total of NOVA Common Shares held
in such Member's Account at such time.

6.   MAINTENANCE OF MEMBER'S ACCOUNT

6.1  A Member's Account will be maintained by the Custodian for each Member
which will record:

     (a) the Member's Contributions to the Plan and any Withholding Amounts
     withheld by the Corporation therefrom;

     (b) the number of NOVA Common Shares purchased with the Contributions which
     have been deposited to the Member's Account;

     (c) the number of NOVA Common Shares purchased or acquired on behalf of the
     Member from amounts paid to such Member's Account by way of dividends or
     distributions on or in respect of NOVA Common Shares held for the Member in
     such Member's Account;

     (d) cash or property received by a Member by way of dividend or
     distributions on or in respect of NOVA Common Shares held for a Member in
     such Member's Account; and

     (e) interest earnings and dividends as they accrue from time to time on
     assets held for the Member in the Member's Account.

6.2  No NOVA Common Shares or other property held in a Member's Account may be
withdrawn from the Plan except in the manner and in the circumstances provided
in Article 9.

6.3  Subject to Article 9, all voting and other rights associated with
beneficial ownership of NOVA Common Shares and other property held in a Member's
Account shall be exercisable by the Member.

6.4  In the event that there is a takeover bid or issuer bid (each as defined in
the applicable Canadian or United States securities laws) for any outstanding
NOVA Common Shares or an offer or proposal to engage in any transaction whereby
a person could acquire control of or a

<PAGE>
                                       6

significant interest in the Corporation, in which holders of NOVA Common Shares
are entitled or encouraged to participate, a Member may participate in any such
transaction on compliance with such procedures as the Custodian or NOVA may
prescribe from time to time.

7.   VESTING

7.1  All Contributions payable by the Corporation to a Member and deposited to
the Member's Account shall vest in the Member on the date upon which such
Contribution is deposited to the Fund.

7.2  All interest earnings and dividends received by the Custodian and arising
from Contributions by the Corporation to a Member's Account shall vest in the
Member on the date on which such interest earnings and dividends were so
received by the Custodian.

8.   ASSIGNMENT

8.1  All monies payable to, or NOVA Common Shares transferable to, a Member or a
beneficiary or any other person pursuant to the provisions of the Plan are for
the provision of benefits to such Member, beneficiary or other person, are not
capable of assignment or alienation and do not confer upon any Member,
beneficiary or any other person, any right or interest in the monies or NOVA
Common Shares which is capable of being assigned or otherwise alienated. Monies
and NOVA Common Shares payable or transferable under the Plan shall not be
assigned, attached, alienated, sold, transferred, pledged, encumbered or given
as security, and to the extent permitted by law, shall not be subject to
attachment, execution or seizure. Any transaction purporting to assign, attach,
alienate, sell, transfer, pledge, encumber, charge, or give as security any
monies or NOVA Common Shares payable or transferable under the Plan shall be
void and of no force or effect.

9.   WITHDRAWALS

9.1  A Member may up to four times per calendar year upon submitting a Notice to
the Corporation and the Custodian withdraw, in accordance with Sections 9.2 and
9.3, all or some portion of the Assets in such Member's Account at such time. In
the event a Member wishes to withdraw all of the Assets in such Member's
Account, which Assets include NOVA Common Shares, such instructions shall be
deemed to include an instruction to withdraw the Assets received by the
Custodian on behalf of the Member in respect of any distribution or dividend on
such NOVA Common Shares after the applicable date.

9.2  The Member has the option of withdrawing NOVA Common Shares from such
Member's Account or a portion thereof in certificate or book-entry form and,
failing any instructions to the contrary, the Member shall be deemed to have
elected to withdraw all such NOVA Common Shares in certificate form.

9.3  Subject to Section 9.1 hereof, a Member is entitled to request a withdrawal
of Assets in cash, in which case the Custodian will be required to sell a
portion or all of the NOVA Common Shares and/or properties in the Member's
Account as so designated in the Notice submitted by the Member. The Custodian
will, within two business days following the sale of NOVA

<PAGE>
                                       7

Common Shares, provide to such Member and the Corporation a statement showing
the number of NOVA Common Shares sold on behalf of such Member, the sale price
obtained therefor and the cumulative total of NOVA Common Shares held in such
Member's Account at such time.

9.4  In the event of the death of a Member, participation in the Plan of such
Member shall be terminated and at the option of the beneficiary or if no
beneficiary has been specified, at the option of the estate of the Member, the
NOVA Common Shares in the number held in such Member's Account or a portion
thereof (as specified by the beneficiary or if no beneficiary has been
specified, by the estate of the Member) and all other Assets held in such
Member's Account as at the date of death of such Member shall be paid and
delivered by the Custodian to the beneficiary or estate of the Member as
previously designated by the Member.

9.5  When a Member ceases to hold office as a Director as a result of expiry of
term of office, resignation, removal or disqualification or if a Member elects
to terminate participation in the Plan by submitting a Notice to the Custodian
and the Corporation, participation in the Plan of such Member shall be
terminated and the Assets held in such Member's Account as at the date of such
expiry of term, resignation, removal or disqualification or date of elected
termination shall be delivered and paid to such Member by the Custodian, such
delivery or payment to occur within such reasonable time after the expiry of
term, resignation, removal or disqualification or elected termination as is
required for determination or processing. Any Contributions to which such Member
may be entitled after such date will be promptly paid to such Member by the
Custodian upon the Corporation's payment thereof to the Custodian.

9.6  When a Member ceases to hold office as a Director as a result of death,
expiry of term of office, resignation, removal or disqualification or when a
Member submits a Notice to the Custodian and the Corporation electing to
terminate participation in the Plan, the Member shall cease to be a Member as of
the date of such death, expiry of term, resignation, removal, disqualification
or elected termination and thereafter shall have no rights under this Plan
except that of receiving the NOVA Common Shares in the number held in such
Member's Account and all other Assets held in such Member's Account in
accordance with Sections 9.4 or 9.5, as the case may be.

10.  THE COMMITTEE

In order to provide for the orderly administration of the Plan, the Board of
Directors may appoint a committee composed of members of the Board of Directors
and officers of the Corporation (herein referred to as the "Committee") to be
structured in the manner and vested with such powers, authorities and
discretions as described below:

10.1 STRUCTURE

     (a) The Committee shall annually elect a member of the Committee to be
     chairman.

     (b) The Committee shall annually appoint a secretary who shall maintain
     minutes and records of all proceedings and transactions of the Committee.

<PAGE>
                                       8

     (c) The Committee from time to time may fix its quorum for the transaction
     of any business at not less than a majority of its members (which minimum
     shall be the quorum until so fixed) and no business shall be transacted by
     the Committee except by resolution in writing signed by all members of the
     Committee or at a meeting of members at which a quorum is present in person
     or by means of telephone or other telecommunications device that permits
     all persons participating in the meeting to speak to and hear each other.

     (d) The Committee may appoint a sub-committee to oversee the administration
     of the Plan, the members of which shall not be limited to the Committee
     members. This sub-committee shall have the right of sub-delegation.

     (e) Except as limited herein or by the resolution of the Board of
     Directors, the Committee may regulate the procedures to be followed at its
     meetings.

10.2 POWERS, AUTHORITIES AND DISCRETIONS

     (a) Subject to the discretion of the Board of Directors, the Committee
     shall be responsible for the proper and orderly administration of the Plan,
     including but not limited to the following:

          (i) approval for filing and filing of such reports, returns and
          submissions as are required by all persons and bodies having competent
          jurisdiction over the Plan;

          (ii) determination of all questions of interpretation and application
          of the Plan and any document or agreement written or entered into
          pursuant to the Plan;

          (iii) recommending changes to the Plan and any document or agreement
          written or entered into pursuant to the Plan.

     (b) The Committee shall cause the accounts of the Plan and Fund to be
     audited annually by the auditor appointed in that regard by the Board of
     Directors which auditors may be the same as the Corporation's auditors.

     (c) The Committee shall recommend to the Board of Directors the appointment
     of auditors and custodians for Members of the Plan and shall be responsible
     for the approval and payment of the fees and charges of such auditors and
     custodians. The Committee may appoint such other advisors and counsel as
     are necessary or deemed by the Committee to be advisable for the proper
     administration of the Plan. The Committee and the Board of Directors shall
     be entitled to rely conclusively upon all tables, valuations,
     certifications, opinions and reports which shall be furnished by an
     accountant, legal counsel or other such professional personal who shall be
     employed or engaged for such purposes.

     (d) The Committee shall annually cause to be prepared a report of the
     operation and administration of the Plan up to the end of the fiscal period
     covered by the auditor's

<PAGE>
                                       9

     report. The Board of Directors will consider and review the report and if
     the Board of Directors is satisfied with the contents thereof the Board of
     Directors will accept the report.

11.  MANAGEMENT OF THE FUND

11.1 The Fund comprises the aggregate of the Members' Accounts. To facilitate
operation of the Plan, the Corporation shall, on behalf of the Members, enter
into a Custodian Agreement to provide for the holding and investing of the
Contributions to the Plan together with the accretions thereto and the income
derived therefrom in accordance with the terms of the Plan and the instructions
of the Members and to provide safekeeping and custodial services in respect of
the Fund. No Member, Member's estate or other person shall have any rights in or
to any part of the principal or income of the Fund or any part of the Assets
thereof, except when and to the extent expressly set out in the Plan.

11.2 The Custodian shall be in an arm's length relationship with the Corporation
and shall be appointed by the Corporation and each Member as custodian and agent
for and on behalf of such Member, with such rights, powers and authorities as
are set forth in the Custodian Agreement. The Custodian shall invest the Fund in
investments authorized by and in accordance with the Plan.

11.3 All expenses reasonably incurred in connection with the administration of
the Plan including, but not limited to, legal fees, accounting fees and
consulting fees, shall be paid by the Corporation. Except as noted below in this
Section 11.3, all expenses reasonably incurred in connection with the Fund
including, but not limited to, fees of the Custodian, expenses incurred by the
Custodian in managing and holding the Fund and the Assets thereof, taxes,
governmental assessments, and similar charges shall be paid by the Corporation.
Stock brokerage charges on the purchase and sale of NOVA Common Shares shall be
paid out of the Contributions deposited to a Member's Account in the case of a
purchase of NOVA Common shares and out of the proceeds of sale in the case of a
sale of NOVA Common Shares.

12.  AMENDMENTS TO AND TERMINATION OF THE PLAN

12.1 Subject to the provisions of this Article 12, and to any requirements of
applicable law, the Board of Directors reserves the right to amend or terminate
the Plan at any time.

12.2 Notwithstanding the foregoing, the Board of Directors may delegate to the
Committee, the responsibility for approval of administrative amendments to the
Plan and, if such delegation occurs, the Committee will, on an annual basis,
report such administrative amendments to the Board of Directors. The Committee
may sub-delegate this responsibility for approval of administrative amendments
to the sub-committee appointed pursuant to Section 10.1(d).

12.3 Notwithstanding the foregoing, no amendment or termination of the Plan
shall adversely affect the right of a Member, a Member's estate, or a Member's
beneficiary, as the case may be, to receive the value of the Member's Account in
accordance with the terms of the Plan.

<PAGE>
                                       10

12.4 The Committee may correct manifest errors and typographical or clerical
mistakes in the text of the Plan and the proper officers of the Corporation may
execute all such documents as may be necessary to correct such errors and
mistakes. Any such documents shall be filed with the Custodian.

12.5 No amendment, change or modification shall be made in the Plan which will,
without the Custodian's written consent, alter the duties of the Custodian.

12.6 In the event the Plan is terminated, all Assets held in a Member's Account
as at the date of termination shall be delivered and paid to such Member in
kind, unless the Member requests payment in cash, such delivery or payment to
occur within such reasonable time after the date of termination as is required
for determination or processing the delivery and payment of Assets under this
Section 12.6.

13.  LIABILITY

13.1 The Corporation and the Custodian shall not be liable to a Member for any
losses incurred by such Member resulting from any delays or other irregularities
in respect of the administration of the Plan whether such losses resulted from
the negligence of the Corporation or the Custodian or otherwise.

14.  MISCELLANEOUS

14.1 The Plan has been established and is maintained as a voluntary and
unilateral undertaking of the Corporation and shall not give or be deemed to
give any Member a right to continued appointment as a Director and shall not
interfere with any right of the shareholders of the Corporation to remove any
Member as a Director at any time. Any benefit to which a Member may be entitled
hereunder shall for all purposes under this Plan or otherwise be deemed an
additional benefit of being a Director. The Corporation expressly disavows the
creation of any rights in Directors, beneficiaries or alternate payees or any
obligations on the part of the Corporation or the Committee, except as expressly
provided herein.

14.2 The Plan has been established for the exclusive benefit of the Members and
their beneficiaries and the Corporation shall have no right, title to, nor
interest in, the Contributions made to the Fund, and no part of the Fund shall
revert to the Corporation except that, in the case of a Contribution which is
made by a mistake of fact, such mistaken Contribution shall be returned to the
Corporation within (1) year after such mistaken Contribution is made.

14.3 Any action taken in good faith by the Committee in the exercise of
authority conferred upon it by the Plan shall be conclusive and binding upon the
Members, their beneficiaries and alternate payees.

14.4 Neither the Corporation, the Board of Directors (or any member thereof) nor
the Committee (or any member thereof) shall be liable for any breach of
fiduciary responsibility resulting from the act or omission of any other
fiduciary or any person to whom fiduciary responsibilities have been allocated
or delegated.

<PAGE>
                                       11

14.5 The Corporation does not intend to create additional fiduciary liability or
to characterize actions or responsibilities as fiduciary in nature beyond that
required by law.

14.6 To the extent permitted by law, the Corporation hereby indemnifies each
member of the Board of Directors and the Committee, and any other employee of
the Corporation with duties under the Plan, against expenses (including any
amount paid in settlement) reasonably incurred by him or her in connection with
any claims against him or her by reason of his or her conduct in the performance
of his or her duties under the Plan, except in relation to matters as to which
he or she acted fraudulently or in bad faith in the performance of such duties.
The preceding right of indemnification shall be in addition to any other right
to which the Board of Directors or Committee members or any other person may be
entitled as a matter of law or otherwise and shall pass to the estate of such
person.

14.7 Notwithstanding any other provision of the Plan, the Corporation may
refrain from doing anything otherwise required herein which would or might, in
the Corporation's opinion be contrary to the law of any jurisdiction or any
official directive or render the Corporation liable to any person otherwise than
as provided or contemplated herein.

15.  INTERPRETATION

15.1 The Plan shall be governed, construed and administered in accordance with
the laws of the Province of Alberta, Canada.

15.2 In this text words importing the singular meaning shall include the plural
and vice versa, and words importing the masculine shall include the feminine and
neuter genders.

15.3 The invalidity or unenforceability of any provision of this Plan shall not
affect the validity or enforceability of any other provision and any invalid or
unenforceable provision shall be severed from this Plan.

DATED at Calgary, Alberta as of May 10, 1994.<PAGE>
                                                                     EXHIBIT 4.6

             THE NOVA CHEMICALS CORPORATION DEFERRED SHARE UNIT PLAN
                                FOR KEY EMPLOYEES

SECTION 1.        PURPOSE

The purpose of the NOVA Chemicals Corporation Deferred Share Unit Plan for Key
Employees is to significantly strengthen the link between employee and
shareholder interests by encouraging Key Employees to voluntarily elect to have
a portion of their compensation tied to the long term performance of the Shares.

SECTION 2.        DEFINITIONS

For the purposes of the Plan:

(a)  "Affiliate" means an Affiliate of the Corporation as that term is defined
     in paragraph 3 of Revenue Canada's Interpretation Bulletin IT-337R3,
     RETIRING ALLOWANCES;

(b)  "Aggregate Purchase Price" has the meaning assigned thereto in Section 9
     hereof;

(c)  "Agreement" means the agreement as it may be amended from time to time,
     entered into by the Corporation and an Eligible Key Employee pursuant to
     Sections 6 and 6.1 hereof in connection with the grant of an award of Bonus
     DSUs and/or Discretionary DSUs hereunder to said Eligible Key Employee and
     setting forth the related rights and obligations of the Corporation and of
     the Eligible Key Employee;

(d)  "Board" means the Board of Directors of the Corporation;

(e)  "Bonus DSU" means a unit credited by means of a bookkeeping entry on the
     books of the Corporation to a Participant's account which is granted in
     accordance with Section 6 and administered in accordance with the terms and
     conditions of the Plan, the value of which on a particular date, shall be
     equal to the Market Value of a Share;

(f)  "Broker" has the meaning assigned thereto in Section 13 hereof;

(g)  "Change in Control" means any change in the holding, direct or indirect, of
     the securities of the Corporation as a result of which a person (as defined
     in the Alberta Business Corporations Act), or a group of persons, are in a
     position to exercise effective control of the Corporation;

(h)  "Committee" means the committee of directors of the Corporation whose
     mandate includes all executive compensation matters and which is currently
     named the Human Resources Committee;

<PAGE>
                                     - 2 -

(i)  "Conversion Date" means, with respect to any calendar year, the date used
     to determine the Market Value of a Share for purposes of determining the
     number of Bonus DSUs to be credited in respect of that year to a Key
     Employee's account, which date shall be the last business day in the year
     immediately preceding the Performance Period;

(j)  "Corporation" means NOVA Chemicals Corporation;

(k)  "Disability Date" means in respect of a Participant, the date as of which
     he or she, as applicable, commences receiving or is eligible to receive
     long term disability benefits under the long term disability plan provided
     by the Corporation or an Affiliate of the Corporation;

(l)  "Discretionary DSU", means a unit credited by means of a bookkeeping entry
     on the books of the Corporation to a Participant's account which is granted
     in accordance with Section 6.1 and administered in accordance with the
     terms and conditions of the Plan, the value of which, on a particular date,
     shall be equal to the Market Value of a Share;

(m)  "Eligible Key Employee" has the meaning assigned thereto in Section 4
     hereof;

(n)  "Entitlement Date" has the meaning assigned thereto in Section 9 hereof;

(o)  "Global Dollar Amount" has the meaning assigned thereto in Section 7
     hereof;

(p)  "Key Employee" includes an officer or other employee of the Corporation or
     of any Affiliate of the Corporation who, in the opinion of the Committee,
     has demonstrated a capacity for contributing in a substantial measure to
     the successful performance of the Corporation or of such Affiliate;

(q)  "Management Incentive Compensation" means cash awards under the
     Corporation's Management Incentive Plan, based on corporate and business
     unit performance and individual contribution to the Corporation's results,
     measured against predetermined objectives, that may be payable to an
     employee of the Corporation or an Affiliate in respect of a Performance
     Period;

(r)  "Market Value" of one Share on any particular day means the average of the
     closing prices for a board lot of Shares on The Toronto Stock Exchange on
     the five (5) trading days immediately preceding the particular date, or if
     at least one board lot of Shares shall not have been traded on The Toronto
     Stock Exchange on any such day, on the immediately preceding day for which
     at least one board lot was so traded; or if, at any time, the Shares are no
     longer listed on The Toronto Stock Exchange, then the Market Value shall be
     calculated on the basis of the average closing price, as aforesaid, for a
     board lot of Shares on the stock exchange on which the Shares are listed
     and had the greatest volume of trading during such five day period. The
     Market Value shall always depend on the fair market value of a Share or a
     share of a corporation related to the Corporation;

(s)  "Participant" means an Eligible Key Employee who has been granted Bonus
     DSUs or Discretionary DSUs under the Plan;

<PAGE>
                                     - 3 -

(t)  "Plan" means the NOVA Chemicals Corporation Deferred Share Unit Plan for
     Key Employees, as amended from time to time;

(u)  "Performance Period" means a calendar year in respect of which an Eligible
     Key Employee may be or become entitled to an award of Bonus DSUs or
     Management Incentive Compensation, or both;

(v)  "Price per Share" has the meaning assigned thereto in Section 9 hereof;

(w)  "Share" means a common share without nominal or par value, of the capital
     stock of the Corporation;

(x)  "Termination Date" means the earliest date on which both of the following
     conditions are met: the Key Employee (1) has ceased to be employed by the
     Corporation or any Affiliate for any reason whatsoever, including
     termination of employment by the employer (whether or not for cause),
     voluntary resignation, retirement from active employment or death of the
     Key Employee, and (2) is not a Director of the Board or of the board of an
     Affiliate.

SECTION 3.        ADMINISTRATION OF THE PLAN

Subject to Sections 5, 6, 6.1, and 12 hereof, the Plan shall be administered by
the Committee, beginning with the 1999 calendar year, the whole subject to
applicable corporate and securities law requirements. The Committee shall have
full and complete authority to interpret the Plan, to prescribe such rules and
regulations (including those with respect to the holding of meetings by
telephone) and to make such other determinations as it deems necessary or
desirable for the administration of the Plan. All actions taken and decisions
made by the Committee shall be final, conclusive and binding on all parties
concerned, including, but not limited to, the Participants and their
beneficiaries and legal representatives, the Corporation and its Affiliates,
their employees and shareholders. All expenses of administration of the Plan
shall be borne by the Corporation, including any reasonable brokerage fees
relating to the purchase of Shares under the Plan.

SECTION 4.        ELIGIBILITY

The Board shall, from time to time, prior to the commencement of a calendar year
(except for the 1999 calendar year), determine which Key Employees shall be
eligible to participate in the Plan for such year ("Eligible Key Employees").

SECTION 5.        ELECTION

An Eligible Key Employee may, with respect to any particular Performance Period,
elect to participate in the Plan. In order to elect to participate in the Plan
with respect to any particular Performance Period, an Eligible Key Employee
shall complete and deliver to the Corporation a written election before the last
business day of the calendar year immediately preceding the Performance Period.

<PAGE>
                                     - 4 -

An Eligible Key Employee who elects to participate in the Plan with respect to a
particular Performance Period shall be entitled to elect on an irrevocable basis
to have either 50% or 100% of such Eligible Key Employee's potential Management
Incentive Compensation with respect to that Performance Period provided under
the Plan in the form of Bonus DSUs in lieu of payment under the Corporation's
Management Incentive Plan. With respect to the 1999 Performance Period only, an
Eligible Key Employee will be given 15 business days from the date the
Corporation receives an advance tax ruling from Revenue Canada that the Plan
will be a "prescribed plan or arrangement" under paragraph 6801(d) of the
regulations under the Income Tax Act (Canada) to make the elections described
above for such Performance Period.

SECTION 6.        GRANT OF AWARDS OF BONUS DSUs

Subject to confirmation by the Board, the Committee shall, from time to time,
choose from among Eligible Key Employees who shall have elected, under Section 5
hereof, to participate in the Plan, those to whom it recommends that Bonus DSUs
be awarded and determine, in accordance with Section 7 hereof, the number of
Bonus DSUs which it recommends be awarded to such Eligible Key Employees who
shall have elected to participate in the Plan for a particular Performance
Period. The Committee shall, subject to confirmation by the Board, recommend the
conversion date ("Conversion Date") of each award of Bonus DSUs under the Plan.
Each award of Bonus DSUs shall be confirmed by an instrument in writing issued
by the Corporation to the Participant.

A Participant who shall have been awarded Bonus DSUs under the Plan shall enter
into an Agreement with the Corporation, which shall comply and be consistent
with the terms of the Plan set out herein, with respect to such award of Bonus
DSUs, which Agreement shall be effective and dated as of the Conversion Date of
the award.

The Bonus DSUs shall be credited to the account of the Eligible Key Employee as
of the Conversion Date. The Bonus DSUs will be fully vested upon being credited
to an Eligible Key Employee.

The Participant's entitlement to payment of Bonus DSUs at the Termination Date
shall not be subject to satisfaction, following the Conversion Date, of any
requirements as to any minimum period of employment.

SECTION 6.1.      GRANT OF AWARDS OF DISCRETIONARY DSUs

Regardless of an Eligible Key Employee's election under Section 5, the Chief
Executive Officer of the Corporation, the Chairperson of the Committee or the
Committee may in his, her or its sole discretion (as applicable) grant, from
time to time, Discretionary DSUs to an Eligible Key Employee. With respect to
any potential award of Discretionary DSUs to the Chief Executive Officer of the
Corporation, such award (if any) shall be granted by the Chairperson of the
Committee or the Committee. The Committee, the Chairperson of the Committee or
the Chief Executive Officer of the Corporation, as applicable, shall determine
the date on which such Discretionary DSUs may be granted, which date shall in
any event precede the Eligible Key Employee's Termination Date. The Chief
Executive Officer of the Corporation, the Chairperson

<PAGE>
                                     - 5 -

of the Committee or the Committee may in his, her or its sole discretion (as
applicable) attach time based vesting conditions (which shall be expressed as a
requisite number of months after the date of the grant of the Discretionary
DSUs) to any such grant of Discretionary DSUs which, subject to this Section
6.1, if not attained by the Eligible Key Employee prior to the date of
termination of employment from the Corporation or an Affiliate, as applicable,
shall result in the forfeiture of such non-vested Discretionary DSUs. Each award
of Discretionary DSUs, including any related time based vesting requirement,
shall be confirmed by an instrument in writing issued by the Corporation to the
Participant.

Except as provided in this Section 6.1, if the employment of a Participant is
terminated for any reason following the grant of Discretionary DSUs and prior to
fulfilment of the vesting conditions attached to such grant by the Chief
Executive Officer of the Corporation, the Chairperson of the Committee or the
Committee, as applicable, the Participant shall forfeit all rights, title and
interest with respect to such Discretionary DSUs including, for greater
certainty, any additional Discretionary DSUs granted pursuant to Section 8 in
respect of such Discretionary DSUs.

Notwithstanding any other provision of this Plan, all Discretionary DSUs
recorded in a Participant's account under the Plan, including for greater
certainty any additional Discretionary DSUs granted pursuant to Section 8 in
respect of such Discretionary DSUs, shall vest immediately and shall not be
considered forfeited under this Section 6.1 upon the earliest of the
Participant's death, a Change in Control, the Participant's Disability Date and
the termination of the Plan in accordance with Section 12.

SECTION 7.        COMPUTATION OF AWARDS OF BONUS DSUs

For the purpose of determining the number of Bonus DSUs to be awarded to an
Eligible Key Employee in accordance with Section 6 hereof, the Committee shall
compute the amount of Management Incentive Compensation that would have been
awarded to the Eligible Key Employee had such employee not elected to
participate in the Plan for the relevant Performance Period (the "Global Dollar
Amount"). The Committee shall then award a number of Bonus DSUs (including
fractional Bonus DSUs) to the Eligible Key Employee equal to the quotient
determined by dividing: (i) the product determined by multiplying (a) the
percentage amount elected by the Eligible Key Employee in accordance with
Section 5 hereof, and (b) the Global Dollar Amount, by (ii) the Market Value of
a Share determined on the Conversion Date. The Bonus DSUs shall be credited to
the account of the Eligible Key Employee as of the Conversion Date.

SECTION 8.        DIVIDEND-LIKE AMOUNTS

A Participant's account shall, from time to time during the term of the
Participant's Agreement(s), including the period following the Participant's
Termination Date and until the Entitlement Date referred to in Section 9 hereof,
be credited with additional Bonus DSUs and/or Discretionary DSUs, the number of
which shall be equal to the quotient determined by dividing one hundred percent
(100%) of the dividends declared and that would have been paid to the
Participant if the Bonus DSUs and/or Discretionary DSUs, as the case may be, in
his or her

<PAGE>
                                     - 6 -

account on the relevant record date for dividends on the Shares had been Shares
(excluding stock dividends, but including dividends which may be paid in cash or
in shares at the option of the shareholder) by the Market Value of a Share on
the payment date of such dividends, with fractions computed to four decimal
places.

SECTION 9.        PAYMENT OF BONUS DSUs AND DISCRETIONARY DSUs

Subject to Section 9.1, a Participant or the legal representative of the
Participant's estate, as applicable, may elect the date as of which the value of
the Bonus DSUs and vested Discretionary DSUs credited to the Participant's
account, as may be adjusted pursuant to Section 19 hereof, shall be determined
and payable (the "Entitlement Date") by filing an irrevocable election with the
Corporation no later than November 30 of the calendar year commencing
immediately after the Participant's Termination Date. The Entitlement Date
elected by a Participant or the legal representative of the Participant's
estate, as applicable, pursuant to this Section 9 shall not be before the later
of 15 days after the date on which the election is filed with the Corporation
and 30 days after the Participant's Termination Date and shall not be later than
December 15 of the calendar year commencing immediately after the Participant's
Termination Date. Where a Participant or the legal representative of the
Participant's estate, as applicable, does not elect a particular date within the
permissible period set out above as his Entitlement Date, the Entitlement Date
for such Participant shall be December 15 of the calendar year commencing
immediately after the Participant's Termination Date. The value, determined as
at the Entitlement Date, of the Bonus DSUs and vested Discretionary DSUs
redeemed by or in respect of a Participant shall, after deduction of any
applicable taxes and other source deductions required to be withheld by the
Corporation, be used to purchase on behalf of the Participant or the
Participant's estate, as applicable, Shares on the open market in accordance
with the provisions of this Section 9.

Prior to 11:00 a.m. on the Entitlement Date or, where the Entitlement Date is
not a trading day for Shares on the stock exchange which is relevant for
determining the value of the Bonus DSUs and vested Discretionary DSUs, on the
next such trading day, the Corporation shall notify the Broker as to the number
of whole Shares to be purchased by the Broker on behalf of the Participant or
the Participant's estate, as applicable, on the open market, by dividing the
cash value of the redeemed Bonus DSUs and vested Discretionary DSUs after
deduction of applicable taxes and other source deductions as provided in this
Section 9, by the Market Value of a Share as determined on the Entitlement Date.
As soon as practicable thereafter, the Broker shall purchase on the open market
the number of Shares which the Corporation has requested the Broker to purchase
and notify the Participant, or the Participant's estate, as applicable, and the
Corporation of: a) the aggregate purchase price ("Aggregate Purchase Price") of
the Shares, b) the purchase price per Share or, if the Shares were purchased at
different prices, the average purchase price (computed on a weighted average
basis) per Share ("Price per Share"), c) the amount of any related reasonable
brokerage commission, and d) the settlement date for the purchase of the Shares.
On the settlement date, upon payment of the Aggregate Purchase Price and related
reasonable brokerage commission by the Corporation, acting as an agent for the
Participant or the Participant's estate, on or before the settlement date, the
Broker shall deliver to

<PAGE>
                                     - 7 -

the Participant or to his representative a certificate representing the Shares
purchased on behalf of the Participant or the Participant's estate, as
applicable.

If, after the Broker applies the value of a Participant's Bonus DSUs and vested
Discretionary DSUs, net of applicable withholdings, to the purchase of whole
Shares as provided for herein, an amount remains payable under the Plan to the
Participant or his or her estate, as applicable, such amount shall be paid in
cash.

The Corporation shall have the right, in its sole discretion, to pay (or cause
the Participant's employer to pay) entirely in cash the value, as computed under
the Plan, of the Bonus DSUs and vested Discretionary DSUs entitlement (less any
applicable withholdings) of the Participant or the Participant's estate, as
applicable, should it deem the regulatory or other requirements of the
applicable jurisdiction associated with the purchase of, or payment in, Shares
too onerous to it or to the Participant, the Participant's estate or the
Participant's employer or if for any other reason it is in the best interest of
the Corporation to make or require such payment in cash.

SECTION 9.1       LIMITATIONS ON ELECTION OF ENTITLEMENT DATE

In the event that a Participant's Termination Date shall occur within ninety
(90) days following a Change in Control of the Corporation, then,
notwithstanding Section 9, the Entitlement Date shall be the fifth trading day
following the Participant's Termination Date. If the Entitlement Date would
otherwise fall between the record date for a dividend on the Shares and the
related dividend payment date then notwithstanding Section 9, the Entitlement
Date shall be the day immediately following the date of payment of such dividend
for purposes of recording in the account of the Participant amounts referred to
in Section 8 hereof and making the calculation of the value of Bonus DSUs and
vested Discretionary DSUs contemplated by Section 9. In the event that the
Corporation is unable, by a Participant's Entitlement Date, to compute the final
number of Bonus DSUs and vested Discretionary DSUs credited to such
Participant's account by reason of the fact that any data required in order to
compute the Market Value of a Share has not been made available to the
Corporation, then the Entitlement Date shall be the next following trading day
on which such data is made available to the Corporation.

In any event and notwithstanding any other provision of the Plan, all amounts
payable to, or in respect of, an Eligible Key Employee hereunder shall be paid
on or before December 31 of the year commencing immediately after the year in
which the Eligible Key Employee's Termination Date occurred.

SECTION 10.       PARTICIPANT'S ACCOUNT

The Corporation shall maintain in its books an account for each Participant
recording at all times the number of Bonus DSUs and Discretionary DSUs standing
to the credit of the Participant. Upon payment in satisfaction of Bonus DSUs and
Discretionary DSUs credited to a Participant in the manner described herein or
upon forfeiture of Discretionary DSUs as provided in Section 6.1, such Bonus
DSUs or Discretionary DSUs, as applicable, shall be cancelled. A written
confirmation of the balance in a Participant's account hereunder shall be mailed
by the Corporation to the Participant at least annually.

<PAGE>
                                     - 8 -

SECTION 11.       EFFECTIVE DATE OF THE PLAN

The effective date of the Plan shall be April 1, 1999.

SECTION 12.       AMENDMENTS TO, SUSPENSION OR TERMINATION OF, THE PLAN

The Board may from time to time amend, suspend or terminate the Plan in whole or
in part. However, any such amendment, suspension or termination shall not
adversely affect the rights accrued to any Participant under any Agreement
existing at the time of such amendment, suspension or termination without the
consent of the affected Participant. Notwithstanding the foregoing, any
amendment or termination of the Plan shall be such that the Plan continuously
meets the requirements of paragraph 6801(d) of the Income Tax Regulations or any
successor provision thereto.

If the Board terminates the Plan, prior awards of Bonus DSUs and Discretionary
DSUs (if any) shall remain outstanding and in effect and paid in due course upon
the Participant's Termination Date for purposes of the Plan in accordance with
the applicable terms and conditions applicable to such Bonus DSUs and
Discretionary DSUs, as applicable, immediately prior to the termination of the
Plan.

SECTION 13.       PURCHASES ON THE OPEN MARKET

Purchases of Shares pursuant to the Plan shall be made on the open market by a
broker independent from the Corporation designated by the Participant and who is
a member of The Toronto Stock Exchange or, where the Shares are not listed on
The Toronto Stock Exchange, the stock exchange which is relevant for determining
the value of the Bonus DSUs and Discretionary DSUs ("Broker"). Any such
designation may be changed from time to time. Upon designation of a Broker or at
any time thereafter, the Corporation may elect to provide the designated Broker
with a letter agreement to be executed by the Broker and entered into with the
Participant and to which the Corporation would also be a party, setting forth,
inter alia, (i) the Broker's concurrence to being so designated, to act for the
Participant's account in accordance with customary usage of the trade with a
view to obtaining the best share price for the Participant, and to delivering to
the Participant or his/her representative the share certificate for the Shares
purchased upon payment by the Corporation of the purchase price and related
reasonable brokerage commission, and (ii) the Corporation's agreement to notify
the Broker of the number of Shares to be purchased and to pay the purchase price
and the related reasonable brokerage commission, provided however that no terms
of said letter agreement shall have the effect of making the Broker or deeming
the Broker to be an affiliate of (or not independent from) the Corporation for
purposes of any applicable corporate, securities or stock exchange requirement.

SECTION 14.       RIGHTS OF PARTICIPANTS

Except as specifically set out in the Plan or an Agreement, no Eligible Key
Employee, Participant or other person shall have any claim or right to any
Shares or other benefit in respect of Bonus DSUs or Discretionary DSUs granted
pursuant to the Plan.

<PAGE>
                                     - 9 -

Neither the Plan nor any award thereunder shall be construed as granting a
Participant a right to be retained as an employee of the Corporation or of any
of its Affiliates or a claim or right to any future grants of Bonus DSUs or
Discretionary DSUs. Neither the Plan nor any action taken thereunder shall
interfere with the right of the employer of an Eligible Key Employee or a
Participant to terminate the employment of such Eligible Key Employee or
Participant at any time. For greater certainty, the payment of any sum of money
in cash in lieu of notice of the termination of employment shall not be
considered as extending the period of employment for the purposes of the Plan.

Under no circumstances shall Bonus DSUs or Discretionary DSUs be considered
Shares nor shall they entitle any Participant to exercise voting rights or any
other rights attaching to the ownership of Shares, nor shall any Participant be
considered the owner of Shares by virtue of this Plan until after the date of
the purchase of such Shares on the open market pursuant to Section 9 hereof.

SECTION 15.       DEATH OF PARTICIPANT

In the event of a Participant's death, any and all Bonus DSUs and Discretionary
DSUs then credited to the Participant's account shall become payable to the
Participant's estate in accordance with Section 9 hereof.

SECTION 16.       COMPLIANCE WITH APPLICABLE LAWS

Any obligation of the Corporation with respect to its Shares pursuant to the
terms of the Plan is subject to compliance with all applicable laws. Should the
Corporation, in its sole discretion, determine that it is not feasible or
practicable to make payment of a Discretionary DSU or a Bonus DSU through the
purchase of Shares on the open market by reason of any such laws, such
obligation shall be satisfied by means of an equivalent cash payment. The
Participant shall comply with all such laws and furnish the Corporation with any
and all information and undertakings as may be required to ensure compliance
therewith.

SECTION 17.       WITHHOLDING TAXES

The Corporation shall be entitled to deduct any amount of withholding taxes and
other withholdings from any amount paid or credited hereunder.

SECTION 18.       TRANSFERABILITY

In no event may the rights or interests of a Participant under the Plan be
assigned, encumbered, pledged, transferred or alienated in any way, except to
the extent that certain rights may pass to a beneficiary or legal representative
upon death of a Participant, by will or by the laws of succession and
distribution.

SECTION 19.       ALTERATION OF NUMBER OF DSUS SUBJECT TO THE PLAN

In the event of any stock dividend, stock split or consolidation affecting the
number of Shares, the Bonus DSUs and the Discretionary DSUs credited to a
Participant's

<PAGE>
                                     - 10 -

account under the Plan will be adjusted in the same manner as if each Bonus DSU
and each Discretionary DSU were a Share. In the event of any exchange of shares
or other change in the Shares into a different number or kind of shares of the
Corporation or of any corporation related thereto, or of any other change in the
Shares or shares into which Shares have been changed or for which they have been
exchanged, such equitable adjustments, as the Committee may reasonably
determine, shall be made with respect to the number of Bonus DSUs and
Discretionary DSUs then recorded in the Participant's account under the Plan.
However, no amount will be paid to, or in respect of, a Participant under the
Plan or pursuant to any other arrangement, and no Bonus DSU or Discretionary DSU
will be granted nor will any credit be made to such Participant's account under
the Plan to compensate for a downward fluctuation in the price of Shares, nor
would any other form of benefit be conferred upon, or in respect of a
Participant for such purpose.

SECTION 20.       GOVERNING LAW

The Plan shall be governed by and interpreted in accordance with the laws in
force in the Province of Alberta.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00045-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00045-of-00352.parquet"}]]