<PAGE>

                                 Exhibit 10.23











                                 Key Executive

                               Change-in-Control

                              Severance Agreement





                                  ----------




                     Pacific Century Financial Corporation
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                                   Contents


                                                                            Page


Article 1.     Establishment and Purpose...................................   1


Article 2.     Definitions and Construction................................   2


Article 3.     Severance Benefits..........................................   4


Article 4.     Just Cause..................................................   6


Article 5.     Form and Timing of Severance Benefits.......................   7


Article 6.     Parachute Payments..........................................   7


Article 7.     Other Rights and Benefits Not Affected......................   7


Article 8.     Successors..................................................   8


Article 9.     Administration..............................................   8


Article 10.    Legal Fees and Arbitration..................................   9
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                     Pacific Century Financial Corporation

                                 Key Executive

                     Change-in-Control Severance Agreement



Article 1.   Establishment and Purpose
             -------------------------

     1.1     Effective Date. This Executive Change-in-Control Severance
Agreement (the "Agreement) is made and entered into pursuant to Bancorp's Key
Executive Severance Plan (the "Plan"), and is effective as of this 26th day of
January 26, 2001 (the "Effective Date"), by and between Pacific Century
Financial Corporation ("PCFC"), a Hawaii corporation, and William C. Nelson, an
executive (the "Executive") of PCFC and its subsidiary, Bank of Hawaii (the
"Bank"). This Agreement shall supersede and replace any prior severance
agreement entered into between PCFC and the Executive.

     1.2     Term of the Agreement. The Agreement shall commence as of the
Effective Date written above, and shall continue until the Board of Directors of
PCFC (the "Board") determines, in good faith and in its sole discretion, that
the Executive is no longer to be included in the Plan and so notifies in writing
the Executive during the term of this Agreement of such determination.

             Provided, however, in the event that a Change in Control of PCFC,
as defined in Section 2.1 herein, occurs during the term of this Agreement, this
Agreement shall remain irrevocably in effect for the greater of twenty-four (24)
months from the date of such Change in Control, or until all benefits have been
paid to the Executive hereunder.

             Further, in the event that the Board has knowledge that a third
party has taken steps reasonably calculated to effect a Change in Control of
PCFC, including, but not limited to, the commencement of a tender offer for the
voting stock of PCFC, or the circulation of a proxy to PCFC's shareholders, then
this Agreement shall remain irrevocably in effect until the Board, in good
faith, determines that such third party has fully abandoned or terminated its
effort to effect a Change in Control of PCFC.

     1.3     Purpose of the Agreement. The purpose of this Agreement pursuant to
the Plan, is to advance the interests of PCFC and the Bank by assuring that PCFC
and the Bank will have the continued employment and dedication of the Executive
and the availability of his advice and counsel in the event that an acquisition
or Change in Control of PCFC occurs. This Agreement shall also assure the
Executive of equitable treatment during the period of uncertainty that surrounds
an acquisition or Change in Control, and allow the Executive to act at all times
in the best interests of PCFC and its shareholders.

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     1.4     Contractual Right to Benefits. This Agreement establishes and vests
in the Executive a contractual right to the benefits which he or she is entitled
hereunder, enforceable by the Executive against PCFC. However, nothing herein
shall require PCFC to segregate, earmark, or otherwise set aside any funds or
other assets to provide for any payments hereunder.

             This Agreement shall be considered an unfunded agreement to provide
benefits to a select group of management or highly compensated employees, and is
therefore intended to be a "top-hat" plan exempt from the requirements of the
provisions of Parts 2, 3, and 4 of Title I of ERISA.



Article 2.   Definitions and Construction
             ----------------------------

     2.1     Definitions. Whenever used in the Agreement, the following terms
shall have the meanings set forth below and, when the meaning is intended, the
initial letter of the word is capitalized.

             (a).   "Base Salary" means the annualized salary at the beginning
                    of each Year, which includes all regular basic wages, before
                    reduction for any amounts deferred on a tax-qualified or
                    nonqualified basis, payable in cash to an Executive for
                    services rendered during the Year. Base Salary shall exclude
                    bonuses, incentive compensation, special fees or awards,
                    commissions, allowances, or any other form of premium or
                    incentive pay, or amounts designated by PCFC as payment
                    toward or reimbursement of expenses.

             (b).   "Beneficial Owner" shall have the meaning ascribed to such
                    term in Rule 13d-3 of the General Rules and Regulations
                    under the Securities Exchange Act of 1934, as amended (the
                    "Exchange Act").

             (c).   "Beneficiary" with respect to an Executive means the person
                    or entities designated or deemed designated by an Executive
                    pursuant to Section 8.2 herein.

             (d)    "Board" means the Board of Directors of PCFC.

             (e)    "Change in Control" of PCFC means any one or more of the
                    following occurrences:

                    (i)     Any Person, including a "group" as defined in
                            Section 13(d)(3) of the Securities Exchange Act of
                            1934, becomes the beneficial owner of shares of PCFC
                            having 25 percent or more of the total number of
                            votes that may be cast for the election of Directors
                            of PCFC; or

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                    (ii)    As the result of, or in connection with, any cash
                            tender or exchange offer, merger or other business
                            combination, sale of assets or contested election,
                            or any combination of the foregoing transactions,
                            the person who were Directors of PCFC before the
                            transaction shall cease to constitute a majority of
                            the Board of Directors of PCFC or any successor to
                            PCFC.

             (f)    "Code" means the Internal Revenue Code of 1986, as amended.

             (g)    "PCFC" means Pacific Century Financial Corporation, a Hawaii
                    corporation, or any successor thereto that adopts the
                    Agreement, as provided in Section 8.1 herein.

             (h)    "Committee" means the Compensation Committee of the Board of
                    Directors of PCFC or any other committee appointed by the
                    Board to administer this Agreement.

             (i)    "Disability" means a physical or mental condition which
                    renders an Executive unable to discharge his or her normal
                    work responsibility with PCFC or the Bank and which, in the
                    opinion of a licensed physician selected by the Executive,
                    subject to reasonable approval by the Committee based upon
                    sufficient medical evidence, can be reasonably expected to
                    continue for a period of at least one full calendar year. If
                    an Executive fails to select a physician with ten (10)
                    business days of a written request made by PCFC, then PCFC
                    may select a physician for purposes of this paragraph.

             (j)    "Effective Date" means the date the Agreement is approved by
                    the Board, or such other date as the Board shall designate
                    in its resolution approving the Agreement, and as provided
                    in Section 1.1 herein.

             (k)    "Effective Date of Termination" means the date on which a
                    voluntary employment termination or involuntary employment
                    termination other than for Just Cause occurs within twenty-
                    four (24) months of a Change in Control which triggers
                    Severance Benefits hereunder.

             (l)    "ERISA" means the Employee Retirement Income Security Act of
                    1974, as amended from time to time, or any successor act
                    thereto.

             (m)    "Expiration Date" means the date the Agreement expires, as
                    provided in Section 1.2 herein.

             (n)    "Just Cause" means a termination of an Executive's
                    employment by PCFC for which no Severance Benefits are
                    payable hereunder, as provided in Article 4 herein.

             (o)    "Normal Retirement Date" shall mean the date the Executive
                    reaches

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                    65 years of age.

             (p)    "Person" shall have the meaning ascribed to such terms in
                    Section 3(a)(9) of the Exchange Act and used in Sections
                    13(d) and 14(d) thereof, including a "group" as defined in
                    Section 13(d).

             (q)    "Plan" means the Bancorp Hawaii, Inc. Key Executive
                    Severance Plan, adopted April 27, 1983.

             (r)    "Severance Benefit" means the payment of severance
                    compensation as provided in Article 3 herein.

             (s)    "Year" means the consecutive 12-month period beginning each
                    January 1 and ending December 31.

     2.2     Gender and Number. Except where otherwise indicated by the context,
any masculine term used herein also shall include the feminine, the plural shall
include the singular, and the singular shall include the plural.

     2.3     Severability. In the event any provision of the Agreement shall be
held illegal or invalid for any reason, the illegality or invalidity shall not
affect the remaining parts of the Agreement, and the Agreement shall be
construed and enforced as if the illegal or invalid provision had not been
included.

     2.4     Modification. No express provisions of this Agreement may be
modified, waived, or discharged unless such modification, waiver, or discharge
is agreed to by the Executive in writing and approved by the Compensation
Committee of the Board of Directors.

     2.5     Applicable Law. To the extent not preempted by the laws of the
United States, the laws of the State of Hawaii shall be the controlling law in
all matters relating to the Agreement.



Article 3    Severance Benefits
             ------------------

     3.1     Right to Severance Benefits. The Executive shall be entitled to
receive from PCFC Severance Benefits as described in Section 3.2 herein, if
there has been a Change in Control of PCFC, as defined in Section 2.1(e) herein,
and if, within twenty-four (24) months thereafter, the Executive voluntarily
terminates employment or is involuntarily terminated without Just Cause with
PCFC. An Executive shall not be entitled to receive Severance Benefits if the
Executive's employment with PCFC or Bank of Hawaii ends due to an involuntary
termination by PCFC for Just Cause, as provided under Article 4 herein.

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     3.2     Description of Severance Benefits. In the event that an Executive
becomes entitled to receive Severance Benefits, as provided in Section 3.1
herein, PCFC shall pay to the Executive and provide the Executive with the
following:

             (a)    An amount equal to three (3) times the Executive's highest
                    annual Base Salary earned (i) at any time during the three
                    (3) complete fiscal years immediately preceding the
                    Effective Date of Termination, or (ii) if the Executive was
                    not employed during such time period, at any time
                    thereafter; and

             (b)    An amount equal to three (3) times the Executive's highest
                    annual bonus earned under the One-Year Incentive Plan during
                    the three (3) complete fiscal years prior to the Effective
                    Date of Termination, or, if shorter, over the Executive's
                    entire period of employment. However, if the Executive's
                    period of employment is less than one year, the bonus shall
                    be considered zero (0); and

             (c)    An amount equal to three (3) times the Executive's highest
                    annual incentive compensation earned under the Pacific
                    Century Financial Corporation Profit Sharing Plan, the
                    Sustained Profit Growth Plan, or any successor plans thereto
                    over the three (3) complete fiscal years prior to the
                    Effective Date of Termination, or, if shorter, over the
                    Executive's entire period of employment. However, if the
                    Executive's period of employment is less than one year, the
                    average incentive compensation shall be considered zero (0);
                    and

             (d)    An amount equal to the excess of (i) the maximum payment the
                    Executive would have received under the One-Year Incentive
                    Plan if he had continued in the employment of PCFC and the
                    Bank through the end of the performance period following the
                    Effective Date of Termination, and if the Bank had met its
                    maximum performance goals as provided under the terms of the
                    Plan and the maximum amount payable to the Executive had
                    been paid, over (ii) the actual payout under the One-Year
                    Incentive Plan resulting from the Executive's termination of
                    employment; provided however, that in the event the
                    Executive becomes entitled to receive Severance Benefits
                    within the first twelve months of employment, the amount of
                    the payment under this section 3.2 (d) will be the One-Year
                    Incentive Plan payout amount stated in the Executive's offer
                    letter dated December 8, 2000; and

             (e)    A payout under the Sustained Profit Growth Plan, in
                    accordance with the terms of such Plan; and

             (f)    A continuation of all welfare benefits at no direct cost to
                    the Executive, including medical insurance, long-term
                    disability, and group term life insurance for three (3) full
                    years from the Effective Date of Termination

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                    or until the Executive reaches his Normal Retirement Date,
                    whichever occurs earlier.

     3.3     Reduction of Severance Benefits. In the event there are fewer than
thirty-six (36) whole or partial months remaining from the Executive's Effective
Date of Termination until the Executive's Normal Retirement Date, as defined
under the Retirement Plan, then the amounts provided for under Sections 3.2(a),
(b), and (c) above shall be reduced by a fraction, the numerator of which shall
be the number of whole or partial months remaining until the Executive's Normal
Retirement Date, and the denominator of which shall be thirty-six (36).

     3.4     Fringe Benefits. The Executive's participation in fringe benefits
prior to the Executive's Effective Date of Termination shall be continued, or
equivalent benefits shall be provided, at no cost to the Executive, for a period
of three (3) years from the Executive's Effective Date of Termination (or until
he or she reaches his Normal Retirement Date, whichever occurs earlier).

     3.5     Relocation Benefits. Should the Executive move his residence in
order to pursue other business opportunities within two (2) years of Executive's
Effective Date of Termination, the Executive shall be reimbursed for any moving
expenses (as defined in Section 217(b) of the Code) incurred in that relocation
(including taxes, if any, payable on the reimbursement) which are not reimbursed
by another employer. Benefits provided herein shall not exceed the assistance
and benefits customarily provided by PCFC to transferred employees prior to the
Change in Control.

     3.6     Incentive Compensation. Any deferred awards previously granted to
the Executive under PCFC's incentive compensation plans and not previously paid
to the Executive, shall immediately vest on the date of the Executive's
Effective Date of Termination and shall be paid no later than ninety (90)
calendar days following that date, and be included as compensation in the month
paid.

     3.8     Stock Options and SARs. Stock options ("options") and stock
appreciation rights ("SARs"), if any, granted to the Executive by PCFC will be
exercisable pursuant to the terms of the applicable plans.



Article 4.   Just Cause
             ----------

     4.1     Just Cause. Nothing in this Agreement shall be construed to prevent
PCFC or the Bank from terminating an Executive's employment for Just Cause. In
such case, no Severance Benefits shall be payable to the Executive under this
Agreement.

             Just Cause shall mean the criminal conviction of the Executive for
an act of fraud, embezzlement, theft or any other act constituting a felony.

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             The determination that the Executive's actions constitute Just
Cause for termination shall be made by the Board, acting in good faith.



Article 5.   Form and Timing of Severance Benefits
             -------------------------------------

     5.1     Form and Timing of Severance Benefits. The Severance Benefits
described in Sections 3.4(a), (b), (c) (d) and 3.8 herein, shall be paid in cash
to the Executive in a single lump sum as soon as practicable following the
Executive's Effective Date of Termination, but in no event beyond ninety (90)
calendar days from such date.

             The Severance Benefits described in Section 3.2(f) and 3.5 herein
shall be provided by PCFC to the Executive immediately upon the Executive's
Effective Date of Termination and shall continue to be provided for three (3)
full calendar years from the Executive's Effective Date of Termination or until
the Executive reaches his or her Normal Retirement date, whichever occurs
earlier.

     5.2     Withholding of Taxes. PCFC shall withhold from any amounts payable
under this Agreement all Federal, state, city, or other taxes as legally shall
be required.



Article 6.   Parachute Payments
             ------------------

     6.1     Excise Tax Cap. In the event that a Change in Control of PCFC shall
occur and a determination is made by PCFC, pursuant to Sections 280G and 4999 of
the Code (and corresponding state law provisions) that a golden parachute excise
tax is due, the Executive's Severance Benefits under this Plan shall be grossed
up for the amount equal to and only equal to the amount necessary to pay the
excise tax.

     6.2     Subsequent Recalculation. In the event the Internal Revenue Service
adjusts the excise tax computation of PCFC, as provided in Section 6.1 herein,
such that the Executive is liable for the payment of a greater excise tax under
Sections 280G and 4999 of the Code, or such that the Executive does not receive
the full benefit that he or she would have received, PCFC shall reimburse the
Executive for the full amount necessary to make the Executive whole (less any
amounts received by the Executive that he or she would not have received had the
computation initially been computed as subsequently adjusted), including the
value of the excise tax and all corresponding interest and penalties due to the
Internal Revenue Service.



Article 7.   Other Rights and Benefits Not Affected
             --------------------------------------

     7.1     Other Benefits. Neither the provisions of this Agreement nor the
Severance Benefits provided for hereunder shall reduce any amounts otherwise
payable, or in any way

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diminish the Executive's rights as an employee of PCFC, whether existing now or
hereafter, under any benefit, incentive, retirement, stock option, stock bonus,
stock purchase plan, or any employment agreement, or other plan or arrangement.

     7.2     Employment Status. This Agreement does not constitute a contract of
employment or impose on the Executive or PCFC any obligation to retain the
Executive as an employee, to change the status of the Executive's employment, or
to change PCFC's policies regarding termination of employment.



Article 8.   Successors
             ----------

     8.1     Successors. PCFC will require any successor (whether direct or
indirect, by purchase, merger, consolidation, or otherwise) of all or
substantially all of the business and/or assets of PCFC or of any division or
subsidiary thereof to expressly assume and agree to perform this Agreement in
the same manner and to the same extent that PCFC would be required to perform it
if no such succession had taken place. Failure of PCFC to obtain such assumption
and agreement prior to the effectiveness of any such succession shall be a
breach of this Agreement and shall entitle the Executive to compensation from
PCFC in the same amount and on the same terms as they would be entitled
hereunder if terminated voluntarily following a Change in Control. Except for
the purposes of implementing the foregoing, the date on which any succession
becomes effective shall be deemed the Effective Date of Termination.

             This Agreement shall inure to the benefit of and be enforceable by
the Executive's personal or legal representatives, executors, administrators,
successors, heirs, distributees, devisees, and legatees. If an Executive should
die while any amount would still be payable hereunder had the Executive
continued to live, all such amounts, unless otherwise provided herein, shall be
paid in accordance with the terms of this Agreement, to the Executive's devisee,
legatee, or other designee, or if there is no such designee, to the Executive's
estate.

     8.2     Beneficiaries. The beneficiary of the Executive under the Pacific
Century Financial Corporation Money Purchase Plan shall be the beneficiary of
the Executive's benefits under this Agreement, unless a beneficiary is otherwise
designated by the Executive in the form of a signed writing acceptable to the
Committee. An Executive may make or change such designation at any time.



Article 9.   Administration
             --------------

     9.1     Administration. This Agreement shall be administered by the
Compensation Committee of the Board of Directors. The Committee is authorized to
interpret this Agreement, to prescribe and rescind rules and regulations, to
provide conditions and assurances deemed necessary and advisable, to protect the
interests of PCFC, and to make all other determinations necessary or advisable
for the Agreement's administration.

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<PAGE>

             In fulfilling its administrative duties hereunder, the Committee
may rely on outside counsel, independent accountants, or other consultants to
render advice or assistance.

     9.2     Indemnification and Exculpation. The members of the Board, its
agents and officers, directors, and employees of PCFC and its affiliates shall
be indemnified and held harmless by PCFC against and from any and all loss,
cost, liability, or expense that may be imposed upon or reasonably incurred by
them in connection with or resulting from any claim, action, suit, or proceeding
to which they may be a party or in which they may be involved by reason of any
action taken or failure to act under this Agreement and against and from any and
all amounts paid by them in settlement (with PCFC's written approval) or paid by
them in satisfaction of a judgment in any such action, suit, or proceeding. The
foregoing provision shall not be applicable to any person if the loss, cost,
liability, or expense is due to such person's gross negligence or willful
misconduct.



Article 10.  Legal Fees
             ----------

     10.1    Legal Fees and Expenses. PCFC shall pay all reasonable legal fees,
costs of litigation, and other expenses incurred in good faith by the Executive
as a result of PCFC's refusal to provide the Severance Benefits to which the
Executive becomes entitled under this Agreement, or as a result of PCFC's
contesting the validity, enforceability, or interpretation of the Agreement.
Provided, however, that such payments shall not exceed the amount permitted by
law and PCFC's Restated Articles of Incorporation.

             IN WITNESS WHEREOF, PCFC has caused this Agreement to be executed
by a resolution of the Board of Directors, as of the day and year first above
written.


                                   Pacific Century Financial Corporation

                                   By:  /S/ MICHAEL E. O'NEILL
                                        ------------------------------------
                                   Its: Chairman & Chief Executive Officer

                                   By:  /S/ WILLIAM C. NELSON
                                        ------------------------------------
                                        (Executive)


ATTEST:

/S/ JOSEPH KIEFER
---------------------------

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