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                                                                   EXHIBIT 10.28


                            STOCK PURCHASE AGREEMENT

      STOCK PURCHASE AGREEMENT, dated as of November 20, 2002, between BancWest
Corporation, a Delaware corporation ("SELLER"), and BNP Paribas, a French
societe anonyme ("BUYER").

      WHEREAS, Seller owns all 3,276,535 issued and outstanding shares of Common
Stock, par value $5.00 per share (the "SHARES"), of Bank of the West, a
Californian banking corporation, (the "BANK"); and

      WHEREAS, on March 15, 2002, the Seller acquired all of the 10,864,198
outstanding common shares of United California Bank; and

      WHEREAS, on April 1, United California Bank merged with and into the Bank,
and as a result of such merger, Seller received in exchange for its shares of
United California Bank, 1,456,238 shares of common shares of the Bank, including
the shares represented by the share certificate number 31 issued by the Bank on
November 20, 2002, representing 485,413 common shares of the Bank with an
aggregate fair market value and U.S. Federal income tax basis of $800 million
(the "MINORITY SHARES");

      WHEREAS, Buyer desires to purchase the Minority Shares from Seller upon
the terms and conditions hereinafter set forth; and

      WHEREAS, Buyer and Seller have entered into a Stockholders' Agreement of
even date herewith (the "STOCKHOLDERS' AGREEMENT") concerning the Minority
Shares;

      NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements set forth herein, the parties hereto agree as follows:

      1.    Sale of Minority Shares. Upon the terms and subject to the
conditions set forth in this Agreement, Seller shall sell, transfer and assign
the Minority Shares to Buyer, and Buyer shall purchase the Minority Shares from
Seller for an aggregate purchase price of $800,000,000 (the "PURCHASE PRICE").
Closing of the transactions contemplated hereby shall occur on November 22, 2002
or such other date as the parties may mutually agree (the "PURCHASE DATE"). On
the Purchase Date, (i) Seller shall deliver to Buyer Bank share certificate
number 31 for the Minority Shares duly endorsed to Buyer, or accompanied by a
stock power duly endorsed to Buyer, and (ii) Buyer shall deliver $800,000,000 to
Seller by interbank transfer in immediately available funds to an account
designated by Seller.

      2.    Representations and Warranties of Seller. Seller hereby represents
and warrants to Buyer as follows:

            (a)   Due Authorization; Enforceable Obligation. Seller has full
                  power and authority to execute and deliver this Agreement and
                  to perform its obligations hereunder. This Agreement has been
                  duly authorized by all necessary corporate action on the part
                  of Seller, has been duly executed and


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                  delivered by Seller and constitutes the valid and binding
                  obligation of Seller enforceable against Seller in accordance
                  with its terms.

            (b)   Conflicting Instruments. Neither the execution and delivery of
                  this Agreement nor the consummation of the transactions
                  contemplated hereby will violate or result in any violation of
                  or be in conflict with or constitute a default under any term
                  of the Certificate of Incorporation or By-Laws of Seller or
                  any judgment, decree or order of any court or administrative
                  body applicable to it or any agreement or other instrument or
                  law applicable to it.

            (c)   Title. Except as provided in this Agreement, (i) Seller is the
                  record and beneficial owner of the Minority Shares with sole
                  power to vote and to dispose of the Minority Shares and (ii)
                  the Minority Shares are owned by Seller free and clear of all
                  security interests, liens, claims, encumbrances, charges,
                  restrictions on transfer, proxies and voting and other
                  agreements.

            (d)   Delivery. Seller has, and upon consummation of the
                  transactions contemplated hereby Buyer will acquire, good and
                  marketable title to the Minority Shares, free and clear of all
                  security interests, liens, claims, encumbrances, charges,
                  restrictions on transfer, proxies and voting and other
                  agreements.

      3.    Representations and Warranties of Buyer. Buyer hereby represents and
warrants to Seller that (i) this Agreement has been duly authorized by all
necessary corporate action on the part of Buyer, (ii) this Agreement has been
duly executed and delivered by Buyer and (iii) this Agreement constitutes the
valid and binding obligation of Buyer enforceable against Buyer in accordance
with its terms.

      4.    Miscellaneous

            (a)   Severability. If any term, provision, covenant or restriction
                  of this Agreement is held by a court of competent jurisdiction
                  to be invalid, void or unenforceable, the remainder of the
                  terms, provisions, covenants and restrictions of this
                  Agreement shall remain in full force and effect and shall in
                  no way be affected, impaired or invalidated.

            (b)   Assignment. This Agreement shall be binding upon and inure to
                  the benefit of the parties hereto and their respective
                  successors and permitted assigns, but neither this Agreement
                  nor any rights hereunder shall be assigned by Buyer without
                  the prior written consent of the Seller.

            (c)   Entire Agreement; Amendments. This Agreement constitutes the
                  entire agreement of the parties with respect to the subject
                  matter hereof, notwithstanding any provision of any such
                  documents to the contrary. This Agreement may not be modified,
                  amended, altered or supplemented except upon execution and
                  delivery of a written agreement executed by the Buyer and
                  Seller.

            (d)   Notices. All notices, requests, claims, demands and other
                  communications hereunder shall be in writing and shall be
                  given (and shall be deemed to have


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                  been duly received if so given) by delivery in person or by
                  cable, telegram or telex to the respective parties as follows:

                  If to Seller:

                  BancWest Corporation
                  999 Bishop Street
                  Honolulu, HI 96813
                  Telecopy: (808) 529-6088
                  Attention: General Counsel & Secretary


                  If to Buyer:


                  BNP Paribas
                  3 rue d'Antin
                  75009 Paris, FRANCE
                  Telecopy: + 33 1 40 14 93 96
                  Attention: M. Philippe Bordenave

                  or to such other address as any party may have furnished to
                  the other in writing in accordance herewith.

            (e)   Governing Law. This Agreement shall be governed by and
                  construed in accordance with the laws of the State of New
                  York.

            (f)   Counterparts. This Agreement may be executed in several
                  counterparts, each of which shall be an original, but all of
                  which together shall constitute one and the same agreement.

            (g)   Effect of Headings. The section headings herein are for
                  convenience only and shall not affect the construction hereof.

            (h)   Further Assurances. Seller shall, upon the reasonable request
                  by Buyer, execute and deliver any additional documents
                  necessary or desirable to complete the sale, conveyance,
                  transfer and assignment of the Minority Shares.

            (i)   Survival. The warranties, representations, covenants and
                  agreements made pursuant to this Agreement shall survive and
                  continue irrespective of any investigation made by or on
                  behalf of any party.

            (j)   Specific Performance. Seller acknowledges that performance of
                  its obligations hereunder will confer a unique benefit on
                  Buyer and, accordingly, that a failure of performance by
                  Seller is not compassable by money damages. Buyer shall
                  therefore be entitled, without prejudice to the rights and
                  remedies otherwise available to it, to specific performance of
                  all obligations of Seller hereunder.

                  *                    *                    *


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      IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first above written.

                                              BNP Paribas SA


                                              By     /s/ PIERRE MARIANI
                                                  ------------------------------
                                              Name   Pierre Mariani
                                              Title: Executive Vice President


                                              BancWest Corporation


                                              By     /s/ WALTER A DODS, JR.
                                                  ------------------------------
                                              Name   Walter A. Dods, Jr.
                                              Title: Chairman & CEO


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