<PAGE>   1
                                                                   Exhibit 10.15

                                 PNC BANK CORP.
                   OUTSIDE DIRECTORS DEFERRED STOCK UNIT PLAN

1.       DEFINITIONS

         In this Plan, except where the context otherwise indicates, the
following definitions apply:

         1.1. "ACCOUNT" means an unfunded deferred compensation bookkeeping
account established in the name of an Outside Director pursuant to the Plan.

         1.2.  "BOARD" means the Board of Directors of the Corporation.

         1.3. "COMMITTEE" means the committee appointed by the Board to
administer the Plan, all of the members of which shall be "non-employee
directors" as defined in Rule 16b-3(b)(3)(i) under the Exchange Act or any
similar successor rule. Unless otherwise determined by the Board, the Committee
on Corporate Governance of the Board shall be the Committee.

         1.4. "COMMON STOCK" means the common stock, par value $5.00 per share,
of the Corporation.

         1.5.  "CORPORATION" means PNC Bank Corp. or any successor thereto.

         1.6. "DATE OF GRANT" means the date on which a Deferred Stock Unit is
granted by the Committee or such later date as may be specified by the Committee
in authorizing the grant.

         1.7. "DEFERRED STOCK UNIT" means a phantom share of the Corporation's
Common Stock, which may be redeemed and paid only in cash pursuant to the terms
of the Plan.

         1.8. "EFFECTIVE DATE" means November 18, 1999 or such later date as may
be specified in the Board resolution adopting the Plan.

         1.9. "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended, and the rules and regulations promulgated thereunder.

         1.10. "FAIR MARKET VALUE" of a Share means an amount equal to the fair
market value of a Share as determined pursuant to a reasonable method adopted by
the Committee in good faith for such purpose. In the absence of a method of
valuation specifically adopted by the Committee, Fair Market Value shall mean
the closing price of a share of Common Stock on the New York Stock Exchange
composite transactions tape on the valuation date, except as otherwise provided
in Article 9, Section 9.2, determined as of such time on the valuation date as
the Corporation's officers may select for this purpose.


                                       1
<PAGE>   2



         1.11. "GRANTEE" means an Outside Director to whom Deferred Stock Units
have been granted pursuant to Article 6 and credited to the Grantee's Account.

         1.12. "OUTSIDE DIRECTOR" means a member of the Corporation's Board of
Directors who is not on the Date of Grant an officer, as defined in Rule
16a-1(f) under the Exchange Act or any similar successor rule, or employee of
the Corporation or a Subsidiary.

         1.13. "PLAN" means the PNC Bank Corp. Outside Directors Deferred Stock
Unit Plan, as amended from time to time.

         1.14. "SHARE" means a share of authorized but unissued Common Stock or
a reacquired share of Common Stock.

         1.15. "SUBSIDIARY" means a corporation at least 80% of the total
combined voting power of all classes of stock of which is owned by the
Corporation, either directly or through one or more other Subsidiaries.

         1.16. "VALUATION DATE" means March 31, June 30, September 30, and
December 31 of each year, except as otherwise provided in Section 10.1. If any
of the preceding dates is not a date on which the New York Stock Exchange is
open for business, then the next preceding date on which the Exchange is open
for business shall serve as the Valuation Date.

2.       PURPOSE

         The Plan is intended to provide a tax-deferred method of compensation
to assist in attracting, retaining, and motivating Outside Directors of
outstanding ability and to promote the identification of their interests with
those of the shareholders of the Corporation.

3.       ADMINISTRATION

         The Plan shall be administered by the Committee or by the Chairman of
the Committee in the exercise of such authority as the Committee may delegate to
him or her from time to time. In addition to any other powers granted to the
Committee, it shall have the following powers, subject to the express provisions
of the Plan:

         3.1. to determine in its discretion the Date of Grant and number or
dollar value of Deferred Stock Units to be granted to each Outside Director and
the terms upon which Deferred Stock Units may be acquired or forfeited and the
terms and conditions of each grant of Deferred Stock Units, which terms and
conditions need not be identical for each Outside Director;

         3.2.  to construe and interpret the Plan;

         3.3. to make all other determinations and take all other actions
necessary or advisable for the administration of the Plan; and


                                       2
<PAGE>   3



         3.4. to delegate to officers or managers of the Corporation or any
Subsidiary the authority to perform administrative functions under the Plan.

Any determinations or actions made or taken by the Committee pursuant to this
Article shall be binding and final.

4.       ELIGIBILITY

Deferred Stock Units may be granted to each Outside Director (including
Committee members) serving on the Effective Date of the Plan, or elected or
appointed and duly qualified thereafter.

5.       ESTABLISHMENT AND TERMINATION OF ACCOUNTS

         5.1. As of the Effective Date of the Plan, the Corporation shall
establish an Account in the name of each Outside Director serving on the
Effective Date.

         5.2. With respect to Outside Directors elected or appointed and duly
qualified after the Effective Date of the Plan, the Corporation shall establish
an Account in the name of each such Outside Director as of the date on which he
or she is duly qualified to serve on the Board.

         5.3. The Corporation shall terminate an Account promptly upon the
redemption of all Deferred Stock Units credited to the Account and the
distribution of all cash resulting therefrom, following the death or retirement
of the Outside Director.

6.       GRANT OF DEFERRED STOCK UNITS

         6.1. Effective as of each Date of Grant specified by the Committee, the
Corporation shall credit each Grantee's Account with the number of Deferred
Stock Units granted by the Committee to that Grantee.

         6.2. The Committee may elect to authorize an annual grant of Deferred
Stock Units to each Grantee, as of a Date of Grant specified by the Committee.
In such case, the number of Deferred Stock Units (including fractional Deferred
Stock Units) to be credited to a Grantee's Account shall be calculated by
dividing a dollar amount specified by the Committee by the Fair Market Value of
a Share as of the Date of Grant. Grants authorized by the Committee pursuant to
this Section shall be credited by the Corporation to each Grantee's Account as
of each annual Date of Grant until the Committee acts to supersede its standing
grant authorization.

         6.3. In addition to the annual grants of Deferred Stock Units
authorized by Section 6.2, the Committee may authorize grants on a special or
one-time basis to Outside Directors, as of such Date of Grant and for such
purposes as the Committee may deem necessary or appropriate. The number of
Deferred Stock Units credited to a Grantee's Account pursuant to such grants
shall be calculated in the same manner as specified in Section 6.2 for annual
grants.


                                       3
<PAGE>   4



         6.4. All Deferred Stock Units granted pursuant to the Plan shall be
credited directly to the Grantee's Account, subject to the terms and conditions
of the Plan and such elections and designations as the Grantee may make pursuant
to Article 8.

7.       ADJUSTMENTS TO DEFERRED STOCK UNITS FOR DIVIDENDS ON COMMON STOCK

         7.1. Except as otherwise provided in Section 7.3, in the event of the
declaration of a dividend on Common Stock that is payable in cash or property
other than Common Stock, the Corporation shall, on or as promptly as shall be
practicable after the date fixed for payment of such dividend, credit to each
Account a number of Deferred Stock Units (including fractional Deferred Stock
Units) equal in value to the number of Shares of Common Stock which would have
been otherwise purchased using the methodology in effect pursuant to the
Corporation's Dividend Reinvestment and stock Purchase Plan from time to time in
effect ("DRP"). Under the DRP as currently in effect, the purchase price per
Share is 100% of the average of the per Share closing prices of the Common Stock
on the New York Stock Exchange for the last two trading days prior to the date
that the dividend is payable.

         7.2. Except as otherwise provided in Section 7.3, in the event of the
declaration of a dividend on Common Stock that is payable in the form of Common
Stock, or if the Common Stock shall be changed into a different number of shares
of stock of the Corporation through a merger, consolidation, reorganization,
stock split or similar transaction, the Corporation shall, on the date fixed for
determining the stockholders of the Corporation entitled to receive such stock
dividend or to participate in such merger, consolidation, reorganization, stock
split or similar transaction, credit each Account with a number of Deferred
Stock Units (including fractional Deferred Stock Units) equal to the number of
Shares (including fractions thereof, even if fractional shares would not have
been issuable) that the Outside Director would have received as a result of such
stock dividend, merger, consolidation, reorganization, stock split or similar
transaction, if the Outside Director were a stockholder of record on such record
date with respect to a number of Shares equal to the number of Deferred Stock
Units credited to the Account on the payable date.

         7.3 In the case of an Outside Director who elects to receive payment of
Deferred Stock Units either (a) as of the date after the later of the Outside
Director's retirement from the Board or attainment of age 70, or (b) in
installments that commence or continue on or after the later of such retirement
or attainment of age 70, in lieu of the credits and adjustments to the Outside
Director's Account otherwise provided for by Sections 7.1 and 7.2, the Outside
Director's Account shall, with respect to Deferred Stock Units covered by an
election described in the preceding clauses (a) or (b), be credited on or as
promptly as shall be practicable after the date fixed for the payment of the
Common Stock dividend, with a number of Deferred Stock Units (including
fractional Deferred Stock Units) equal in value (determined as hereinafter
provided) to the product of (a) the value (determined as herein provided) of the
Deferred Stock Units credited to the Outside Director's Account and covered by
such election and (b) a fair market interest rate approved by the Committee;
provided, that for purposes of this Section, the value of the Deferred Stock
Units credited to the Outside Director's Account and the number of additional
Deferred Stock Units to be credited shall be determined using the Fair Market
Value of a Share as of the later of the Outside Director's date of retirement
from the Board or attainment of age 70. Notwithstanding the foregoing
provisions, the Corporation's officers may instead elect to assign a notional
equivalent cash value to the Deferred Stock Units which would otherwise be
credited to the Outside Director's Account and to account for the value of the
Account, including interest credited thereto, on that basis.


                                       4
<PAGE>   5

8.       PAYMENT ELECTIONS AND BENEFICIARY DESIGNATIONS BY AN OUTSIDE DIRECTOR

         8.1. With respect to each grant of Deferred Stock Units, each Outside
Director shall have the right to elect: (a) the event or date (which event or
date shall not precede the earlier of the date of the Outside Director's
retirement from the Board or the date on which the Outside Director attains age
70) when the Deferred Stock Units credited to his or her Account shall be
redeemed and paid out in cash; and (b) whether the payment shall be in a lump
sum or in a designated number of annual installments, not to exceed ten annual
installments.

         8.2. Each Outside Director shall also have the right to designate one
or more beneficiaries to receive unpaid amounts in his or her Account in the
event of the Outside Director's death, in accordance with the administrative
procedures and applicable elections and beneficiary payment options then in
effect for the Plan. Unless otherwise specified by the Outside Director, in the
event that a designated beneficiary dies after beginning to receive payments
from the Account but before the payment of all amounts in the Account due to
that beneficiary, the beneficiary's estate shall be entitled to receive such
unpaid amounts in a lump sum. The estate of a beneficiary who has predeceased
the Outside Director shall have no claim to payments under the Plan.

         8.3. In the event that an Outside Director fails to make a payment
election or beneficiary designation, or all designated beneficiaries have
predeceased the Outside Director, the following default elections or
designations shall be deemed to have been made by the Outside Director: (a) the
default payment election shall be a lump-sum payment upon retirement from the
Board; and (b) the default beneficiary designation shall be the Outside
Director's surviving spouse, or if none, the Outside Director's estate.

         8.4. An Outside Director shall have the right to amend or terminate his
or her elections or designations at any time upon completing, signing, dating,
and submitting to the Corporation's Corporate Secretary Department the form of
agreement provided by the Corporation. Amendments or terminations shall be
effective as follows: With respect to payment elections, amendments shall be
effective on the next subsequent Date of Grant. Except as otherwise provided in
Article 10, such amendment shall only apply to Deferred Stock Units or notional
cash value credited (plus adjustments made for dividends or interest pursuant to
Article 7) to the Account after the effective date of the amendment. The
Deferred Stock Units or notional cash value in the Account immediately prior to
the effective date of the amended payment election shall be paid in accordance
with the prior payment election or elections. With respect to beneficiary
designations, amendments or terminations shall be effective immediately upon the
Corporation's Corporate Secretary Department's receipt of a properly completed,
executed, and dated form of agreement.


                                       5
<PAGE>   6
9.       REDEMPTION OF DEFERRED STOCK UNITS

         9.1. The Corporation shall redeem Deferred Stock Units credited to an
Account at such times and in such amounts as may be necessary to distribute cash
in accordance with the elections and designations made by an Outside Director
pursuant to Article 8 and the provisions of Article 10.

         9.2. In the case of an Outside Director who elects to defer the receipt
of Deferred Stock Units until retirement from the Board or attainment of age 70,
or in the event an Outside Director elects to receive payment in the manner
described in Section 9.3 or pursuant to Section 10.3, Deferred Stock Units
covered by such an election shall be valued as of the applicable Valuation Date
at the higher of the following: (a) the Fair Market Value of a Share on the
Valuation Date; or (b) the average Fair Market Value of a Share for all trading
days during the twelve-month period immediately preceding the Valuation Date.
Notwithstanding the foregoing provisions, the twelve-month period immediately
preceding the Valuation Date shall not extend earlier than January 3, 2000.

         9.3 In the case of an Outside Director who elects to receive payment of
Deferred Stock Units either (a) as of a date after the later of the Outside
Director's retirement from the Board or attainment of age 70, or (b) in
installments that commence or continue on or after the later of such retirement
or attainment of age 70, Deferred Stock Units covered by such an election shall
be valued for purposes of redemption using the Fair Market Value of a Share on
the later of the date of the Outside Director's retirement from the Board or
attainment of age 70, except as otherwise provided in Section 9.2. It is the
express purpose of this Section to fix the value of a Deferred Stock Unit as of
the later of the date of an Outside Director's retirement from the Board or
attainment of age 70 in all cases where the redemption is for a payment other
than one paid upon retirement from the Board or attainment of age 70 or an early
withdrawal made pursuant to Section 10.3.

         9.4.  Deferred Stock Units shall be redeemed only for cash.

10.      PAYMENT FOLLOWING THE REDEMPTION OF DEFERRED STOCK UNITS

         10.1. All payments from an Account shall be made solely in cash.
Payment shall commence on or before thirty days after the Valuation Date
immediately following the designated date or the date that the designated event
occurs and the amount to be paid shall be based on the Account balance on such
Valuation Date. Notwithstanding the preceding sentence, the Corporation's
officers may elect to accelerate payment by deeming the designated date or the
date that the designated event occurs to be a Valuation Date and to make payment
within thirty days thereafter. If an Outside Director elects the equal annual
installment payment option, the amount of each installment to be paid shall be
determined by dividing the balance in the Account to be paid in the form of
installments by the number of installments remaining to be paid. The Deferred
Stock Units or notional cash value remaining in an Account subject to
installment payouts shall continue to be adjusted for dividends or interest in
accordance with Article 7. In the event of the death or disability of an Outside
Director, the Committee may accelerate the


                                       6
<PAGE>   7



payment of any installment or lump-sum payment because of hardship or other
circumstances deemed in the sole discretion of the Committee to warrant such
acceleration.

         10.2. Notwithstanding Section 10.1: (a) at any time earlier than twelve
months prior to the date on which a payment of all or a portion of an Account
would be payable, an Outside Director may elect to extend the deferral of all of
his or her Account, or of such portion of his or her Account as would otherwise
be paid; and (b) at any time earlier than twelve months prior to the date on
which a payment of all or a portion of an Account would be payable, an Outside
Director may modify his or her prior payment date election for the Account;
provided, that such modified payment date is on or after the earlier of the date
that he or she expects to retire from the Board or reaches the age of 70.

         10.3. An Outside Director may at any time elect the payment, as soon as
administratively practicable, of all of the balance of his or her Account;
provided, that in each such instance, a 10 percent early withdrawal penalty
shall apply to the amount of the requested early withdrawal. An Outside Director
who makes such an election shall not be eligible to have Deferred Stock Units
credited to his or her Account for two years after the date of the payment
election.

11.      ACCOUNT STATEMENTS

         11.1. A regular quarterly statement of account shall be sent to each
current or former Outside Director with a balance in his or her Account listing
the aggregate number of Deferred Stock Units in the Account, including
adjustments for dividends or interest made pursuant to Article 7, and showing
the aggregate Fair Market Value of such Deferred Stock Units as of each
Valuation Date, respectively. The Corporation's officers may also provide such
additional statements of account as they may deem appropriate from time to time.

         11.2. In the case of an Outside Director who elects to receive payment
of Deferred Stock Units either (a) as of a date after the later of the Outside
Director's retirement from the Board or attainment of age 70, or (b) in
installments that commence or continue on or after the later of such retirement
or attainment of age 70, Account statements after the later of retirement or
attainment of age 70 shall reflect the aggregate Fair Market Value of such
Deferred Stock Units using the Fair Market Value of a Share as of the later of
the date of the Outside Director's retirement from the Board or attainment of
age 70. Notwithstanding the foregoing provisions, the Corporation's officers may
instead elect to assign a notional equivalent cash value to the Deferred Stock
Units which would otherwise be credited to the Outside Director's Account and to
account for the value of the Account, including interest credited thereto, on
that basis.

12.      EFFECTIVENESS OF THE PLAN

         The Plan shall become effective as of November 18, 1999, or such later
date as may be specified in the Board resolution adopting the Plan.


                                       7
<PAGE>   8
13.      TERM OF THE PLAN

         The Plan shall continue in effect until terminated by the Board upon
the Committee's recommendation pursuant to Section 15.8. No Deferred Stock Units
may be granted under Article 6 hereof after termination. The termination of the
Plan shall not affect the validity of any Deferred Stock Unit credited to an
Account on the date of termination.

14.      INDEMNIFICATION OF COMMITTEE

         In addition to such other rights of indemnification as they may have as
directors or as members of the Committee, the members of the Committee shall be
indemnified by the Corporation against the reasonable expenses, including
attorney's fees, actually and reasonably incurred in connection with the defense
of any action, suit or proceeding, or in connection with any appeal therein, to
which they or any of them may be a party by reason of any action taken or
failure to act under or in connection with the Plan or any Deferred Stock Unit
granted hereunder, and against all amounts reasonably paid by them in settlement
thereof or paid by them in satisfaction of a judgment in any such action, suit
or proceeding, if such members acted in good faith and in a manner which they
believed to be in, and not opposed to, the best interests of the Corporation.

15.      MISCELLANEOUS PROVISIONS

         15.1. NO RIGHT OR OBLIGATION OF CONTINUED SERVICE. Nothing contained
herein shall entitle an Outside Director to continue to serve as a member of the
Board or require an Outside Director to continue to provide services as a member
of the Board. The termination of an Outside Director's service as a member of
the Board shall have no effect on his or her rights hereunder, except as
otherwise provided herein.

         15.2. NO STOCKHOLDER RIGHTS. The sole interest of an Outside Director
hereunder shall be the right to receive the payments provided for herein as and
when the same shall become due and payable, and an Outside Director shall have
no rights as a stockholder of the Corporation with respect to Deferred Stock
Units credited to his or her Account.

         15.3. NONALIENABILITY. Except for the withholding of any tax under
applicable law, no Deferred Stock Units credited to an Account or any amount
payable at any time hereunder shall be subject in any manner to alienation,
sale, transfer, assignment, pledge, attachment or other legal process, or
encumbrance of any kind. Any attempt to alienate, sell, transfer, assign, pledge
or otherwise encumber any such Deferred Stock Units or amount, whether currently
or hereafter payable, shall be void. Except as otherwise specifically provided
by law, no Deferred Stock Units or amount payable hereunder shall, in any
manner, be liable for or subject to the debts or liabilities of an Outside
Director or beneficiary.


                                       8
<PAGE>   9
         15.4. WITHHOLDING. Payments made by the Corporation hereunder shall be
subject to any applicable tax withholding requirements and to such other
deductions as shall at the time of such payment be required under any income tax
or other law, whether of the United States or any other jurisdiction.

         15.5. HEADINGS. The headings of Articles and Sections herein are
included solely for convenience of reference and shall not alter the meaning or
interpretation of any of the provisions of the Plan.

         15.6. SUCCESSORS. The Corporation shall require any successor (whether
direct or indirect, by purchase, merger, consolidation or otherwise) to all or
substantially all of the business and/or assets of the Corporation to expressly
assume the Corporation's obligations hereunder in the same manner and to the
same extent that the Corporation would be required to perform if no such
succession had taken place. This Plan shall inure to the benefit of and be
enforceable by each Outside Director and each Outside Director's personal or
legal representatives, beneficiaries, executors, administrators, successors,
heirs, distributees, devisees and legatees.

         15.7. STATUS AS UNSECURED CREDITOR; FUNDING OF PAYMENTS. All Account
balances shall constitute unsecured contractual obligations of the Corporation.
In the sole discretion of the Corporation, the Corporation or any of its
affiliates may establish or maintain a nonqualified grantor trust and make
contributions thereto for the purpose of providing a source of funds to make
payments hereunder as they become due and payable; provided, that no such trust
shall result in an Outside Director or any designated beneficiary being required
to include in gross income for federal income tax purposes any amounts payable
hereunder prior to the date of actual payment. Notwithstanding the establishment
or maintenance of any such trust, Outside Directors' and their designated
beneficiaries' rights hereunder shall be solely those of a general unsecured
creditor of the Corporation.

         15.8. TERMINATION AND AMENDMENT OF PLAN. The Plan may be terminated or
amended at any time by vote of the Board without the consent of any current or
former Outside Director for whom an Account has been established, upon the
Committee's recommendation; provided, that any termination or amendment shall be
of general application to all Outside Directors participating in the Plan (and
their beneficiaries) and shall not, without the specific written consent of any
such Outside Director (or beneficiary) adversely affect: (a) any Deferred Stock
Units or amounts theretofore credited to an Account; or (b) the right of an
Outside Director (or beneficiary) to receive all amounts due and payable with
respect to an Account.

         15.9. GOVERNING LAW. The Plan shall be construed in accordance with and
governed by the laws of the Commonwealth of Pennsylvania, without reference to
its conflicts of laws provisions.



                                       9