Exhibit 4.2


                          AMENDMENT TO RIGHTS AGREEMENT

         This Amendment, dated as of August 15, 2001 (the "Amendment"), is to
the Rights Agreement dated as of January 19, 1999 (the "Rights Agreement"),
between MCB Financial Corporation, a California corporation ( "MCB"), and U.S.
Stock Transfer Corporation (the "Rights Agent").

         WHEREAS, the Board of Directors of MCB has approved an Agreement and
Plan of Reorganization dated as of August 15, 2001 between Business Bancorp
("BB"), a California corporation and MCB providing for the merger of MCB with
and into BB and a related Merger Agreement (such agreements together, the
"Merger Agreements");

         WHEREAS, the Merger Agreements contemplate that MCB, at the time such
agreements are executed, shall have taken all actions necessary to prevent the
Merger Agreements and the transactions contemplated therein from triggering the
Rights (as defined in the Rights Agreement) outstanding under the Rights
Agreement;

         WHEREAS, the Board of Directors has determined that this Amendment is
in the best interests of MCB and its shareholders; and

         WHEREAS, MCB and the Rights Agent have determined that, pursuant to
Section 27 of the Rights Agreement, the Rights Agreement may be amended as set
forth herein without the approval of the holders of the Rights.

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements set forth herein, MCB and the Rights Agent hereby agree as follows:

         1. This Amendment shall become effective on the date that MCB and BB
have both executed the Merger Agreements, immediately before such execution.

         2. Subsection 1(a) of the Rights Agreement is hereby amended to include
the following additional sentence to immediately follow the current language
therein: "Notwithstanding the foregoing, neither Business Bancorp, a California
corporation, nor any of its Affiliates or Associates, shall be an `Acquiring
Person.'"

         3. Section 1 of the Rights Agreement is hereby amended to include a new
Subsection 1(aa) which shall read as follows: "`Section 11(a)(ii) Event' shall
mean any Trigger Event as defined in Section 11(a)(ii)."

         4. Section 1 of the Rights Agreement is hereby amended to include a new
Subsection 1(bb) which shall read as follows:

         "Section 13 Event" shall mean any event described in clause (i), (ii),
         (iii) or (iv) of Section 13(a) of this Agreement, other than the
         delivery, execution or performance or consummation of any of the
         transactions contemplated in the Agreement and Plan of Reorganization
         dated as of August 15, 2001 between Business Bancorp, a California
         corporation and the Company and the related Merger Agreement.


<PAGE>


         5. Section 1 of the Rights Agreement is hereby amended to include a new
Subsection 1(cc) which shall read as follows: "`Trigger Event'" shall mean any
Section 11(a)(ii) Event or any Section 13 Event."

         6. The Rights Agreement is hereby amended to include a new Subsection
(v) to Section 11(a) thereof which shall read as follows:

         (v) Notwithstanding anything in this Agreement to the contrary, the
         execution, delivery, performance or consummation of any of the
         transactions contemplated in the Agreement and Plan of Reorganization
         dated as of August 15, 2001 between Business Bancorp and the Company
         and the related Merger Agreement will not be deemed Trigger Events.

         7. Section 13 of the Rights Agreement is hereby amended to include a
new Subsection 13(f) which shall read as follows:

         (f) Notwithstanding anything in this Agreement to the contrary, this
         Section 13 shall not be applicable to the execution, delivery, or the
         performance or consummation of any of the transactions contemplated in,
         the Agreement and Plan of Reorganization dated as of August 15, 2001
         between Business Bancorp and the Company and the related Merger
         Agreement.

         8. The form of Summary of Rights to Purchase Preferred Shares attached
as Exhibit C to the Rights Agreement is hereby replaced in its entirety by the
form of Summary of Rights to Purchase Common Shares attached as Exhibit A
hereto.

         9. As promptly as practicable following the date of this Amendment, MCB
shall take all appropriate actions to cause the legend on the certificates for
the Common Stock referring to the Rights Agreement to make reference to this
Amendment.

         10. This Amendment shall be limited solely to the matters expressly set
forth herein and shall not (a) prejudice any right or rights which MCB may now
have or may in the future have under or in connection with the Agreement or any
instruments or agreements referred to therein or (b) except to the extent
expressed as set forth herein, modify the Agreement or any Rights, or any
instruments or agreements referred to therein.

         11. Unless defined herein, all capitalized terms shall have the
meanings provided in the Rights Agreement.

         12. This Amendment shall be deemed to be a contract under the laws of
the State of California and for all purposes shall be governed by and construed
in accordance with the laws of such State applicable to contracts to be made and
performed entirely within such State.



                                       2

<PAGE>


         13. This Amendment may be executed in any number of counterparts and
each of such counterparts shall for all purposes be deemed to be an original,
and all such counterparts shall together constitute but one and the same
instrument. Signatures by facsimile transmission are deemed acceptable.

         14. This Amendment shall be for the sole and exclusive benefit of MCB,
the Rights Agent and the registered holders of the Rights Certificates (and,
prior to the Distribution Date, MCB's common shares). Nothing in this Amendment
shall be construed to give any person other than MCB, the Rights Agent and the
registered holders of the Rights Certificates (and, prior to the Distribution
Date, MCB's common shares) any legal or equitable right, remedy or claim under
this Amendment and the Merger Agreement.

         IN WITNESS WHEREOF, the parties have caused this Amendment to be duly
executed and their respective corporate seals to be hereto affixed and attested,
all as of the date and year first above written.

                                   MCB FINANCIAL CORPORATION


                                   By:      /s/Charles O. Hall
                                      ---------------------------------------
                                             Charles O. Hall

                                   Its: President & Chief Executive Officer
                                       --------------------------------------


                                   AMERICAN SECURITIES TRANSFER AND TRUST CO.


                                   By: /s/ William Garza
                                      ---------------------------------------
                                           William Garza

                                   Its:  Vice President
                                       --------------------------









                                       3



                                                                       EXHIBIT A


                 SUMMARY OF RIGHTS TO PURCHASE PREFERRED SHARES



                  On December 17, 1998, the Board of Directors of MCB Financial
Corporation (the "Company") declared a dividend of one preferred share purchase
right (a "Right") for each outstanding share of common stock, no par value (the
"Common Shares"), of the Company. The dividend was payable on February 8, 1999
(the "Record Date") to the shareholders of record on that date. Each Right
entitles the registered holder to purchase from the Company one one-hundredth of
a share of Series A Junior Participating Preferred Stock, no par value (the
"Preferred Shares"), of the Company at a price of $37.00 per one one-hundredth
of a Preferred Share (the "Purchase Price"), subject to adjustment. The
description and terms of the Rights are set forth in a Rights Agreement dated as
of January 19, 1999 (the "Rights Agreement") between the Company and U. S. Stock
Transfer Corporation, as Rights Agent (the "Rights Agent").

                  Initially, the Rights will be attached to all certificates
representing Common Shares then outstanding, regardless of whether any such
certificate has a copy of this Summary of Rights attached thereto, and no
separate Right Certificates will be distributed. The Rights will separate from
the Common Shares and a Distribution Date will occur upon the earlier of (i) 10
days following a public announcement that a person or group of affiliated or
associated persons have acquired beneficial ownership of 10% or more of the
outstanding Common Shares (an "Acquiring Person"); provided, however, a person
or group holding 10% or more of the outstanding shares as of January 19, 1999
will become a "Grandfathered Person" and such Grandfathered Person will be
treated as an Acquiring Person upon public announcement or knowledge by the
Company's Board of Directors that such Grandfathered Person has acquired
beneficial ownership of an additional 1% of the outstanding Common Shares; or
(ii) 10 business days (or such later date as may be determined by action of the
Board of Directors prior to such time as any Person becomes an Acquiring Person)
following the commencement of, or announcement of an intention to make, a tender
offer or exchange offer the consummation of which would result in the beneficial
ownership by a person or group of 10% or more of such outstanding Common Shares
(unless the Company's Board of Directors has approved the offer). On August 15,
2001, the Rights Agreement was amended (the "Amendment") to allow MCB and
Business Bancorp, a California corporation ("BB") to enter into and engage in
the transactions described in an Agreement and Plan of Merger dated August 15,
2001 between MCB and BB pursuant to which MCB will merge with BB (the "BB
Merger") and a related Stock Option Agreement by MCB and BB (such agreements
collectively, the "BB Merger Agreements"). As amended, the Rights Agreement
provides that BB and its Affiliates and Associates will not be Acquiring Persons
as a result of the BB Merger Agreements or the transactions described in those
agreements, nor will consummation of any of the transactions contemplated by the
BB Merger Agreements trigger the exercisability of the Rights described herein.

                  The Rights Agreement provides that, until the Distribution
Date, the Rights will be transferred with and only with the Common Shares. Until
the Distribution Date (or earlier redemption or expiration of the Rights), new
Common Share certificates issued after the Record


                                      C-1

<PAGE>

Date, upon transfer or new issuance of Common Shares, will contain a notation
incorporating the Rights Agreement by reference. Until the Distribution Date (or
earlier redemption or expiration of the Rights), the surrender for transfer of
any certificates for Common Shares outstanding as of the Record Date, even
without such notation or a copy of this Summary of Rights being attached
thereto, will also constitute the transfer of the Rights associated with the
Common Shares represented by such certificate. As soon as practicable following
the Distribution Date, separate certificates evidencing the Rights ("Right
Certificates") will be mailed to holders of record of the Common Shares as of
the close of business on the Distribution Date and such separate Right
Certificates alone will evidence the Rights.

                  The Rights are not exercisable until the Distribution Date.
The Rights will expire on January 30, 2009 (the "Final Expiration Date"), unless
the Rights are earlier redeemed or exchanged by the Company, in each case as
described below.

                  The Purchase Price payable, and the number of Preferred Shares
or other securities or property issuable, upon exercise of the Rights are
subject to adjustment from time to time to prevent dilution (i) in the event of
a stock dividend on, or a subdivision, combination or reclassification of, the
Preferred Shares, (ii) upon the grant to holders of the Preferred Shares of
certain rights or warrants to subscribe for or purchase Preferred Shares at a
price, or securities convertible into Preferred Shares with a conversion price,
less than the then current market price of the Preferred Shares or (iii) upon
the distribution to holders of the Preferred Shares of evidences of indebtedness
or assets (excluding regular periodic cash dividends paid out of earnings or
retained earnings or dividends payable in Preferred Shares) or of subscription
rights or warrants (other than those referred to above).

                  The number of outstanding Rights and the number of one
one-hundredths of a Preferred Share issuable upon exercise of each Right are
also subject to adjustment in the event of a stock split of the Common Shares or
a stock dividend on the Common Shares payable in Common Shares or a subdivision,
consolidation or combination of the Common Shares occurring, in any such case,
prior to the Distribution Date.

                  Preferred Shares purchasable upon exercise of the Rights will
not be redeemable. Each Preferred Share will be entitled to a minimum
preferential dividend payment of 100 times the dividend declared per Common
Share. In the event of liquidation, the holders of the Preferred Shares will be
entitled to a minimum preferential liquidation payment of $100.00 per share but
will be entitled to an aggregate payment of 100 times the payment made per
Common Share. Each Preferred Share will have 100 votes, voting together with the
Common Shares. Finally, in the event of any merger, consolidation or other
transaction in which Common Shares are exchanged, each Preferred Share will be
entitled to receive 100 times the amount received per Common Share. These rights
are protected by customary antidilution provisions.

                  Because of the nature of the Preferred Shares' dividend,
liquidation and voting rights, the value of the one one-hundredth interest in a
Preferred Share purchasable upon exercise of each Right should approximate the
value of one Common Share.


                                      C-2

<PAGE>


                  In the event that (i) any person or group of affiliated or
associated persons becomes an Acquiring Person, or (ii) during such time as
there is an Acquiring Person, there shall be a reclassification of securities or
a recapitalization or reorganization of the Company or other transaction or
series of transactions involving the Company which has the effect of increasing
by more than 1% the proportionate share of the outstanding shares of any class
of equity securities of the Company or any of its subsidiaries beneficially
owned by the Acquiring Person (each a "flip-in" event), proper provision shall
be made so that each holder of a Right, other than Rights beneficially owned by
the Acquiring Person (which will thereafter be void), will thereafter have the
right to receive upon exercise that number of Common Shares (or, in the event
that there are insufficient authorized Common Shares, substitute consideration
such as cash, property, or other securities of the Company, such as Preferred
Stock) having a market value of two times the exercise price of the Right. In
the event that the Company is acquired in a merger or other business combination
transaction or 50% or more of its consolidated assets or earning power are sold
(a "flip-over event"), proper provision will be made so that each holder of a
Right will thereafter have the right to receive, upon the exercise thereof at
the then current exercise price of the Right, that number of shares of common
stock of the acquiring company which at the time of such transaction will have a
market value of two times the exercise price of the Right.

                  At any time after the acquisition by a person or group of
affiliated or associated persons of beneficial ownership of 10% or more of the
outstanding Common Shares and prior to the acquisition by such person or group
of 50% or more of the outstanding Common Shares, the Board of Directors of the
Company may exchange the Rights (other than Rights owned by such person or group
which have become void), in whole or in part, at an exchange ratio of one Common
Share, or one one-hundredth of a Preferred Share (or of a share of a class or
series of the Company's preferred stock having equivalent rights, preferences
and privileges), per Right (subject to adjustment).

                  With certain exceptions, no adjustment in the Purchase Price
will be required until cumulative adjustments require an adjustment of at least
1% in such Purchase Price. No fractional Preferred Shares will be issued (other
than fractions which are integral multiples of one one-hundredth of a Preferred
Share, which may, at the election of the Company, be evidenced by depository
receipts) and in lieu thereof, an adjustment in cash will be made based on the
market price of the Preferred Shares on the last trading day prior to the date
of exercise.

                  At any time before a person becomes an Acquiring Person, the
Board of Directors of the Company may redeem the Rights in whole, but not in
part, at a price of $0.001 per Right (the "Redemption Price"). After the
redemption period has expired, the Company's rights of redemption may be
reinstated if, prior to completion of certain recapitalizations, mergers or
other business combinations, an Acquiring Person reduces its beneficial
ownership to less than 10% of the outstanding Common Shares in a transaction or
series of transactions not involving the Company. The redemption of the rights
may be made effective at such time, on such basis and with such conditions as
the Board of Directors in its sole discretion may establish. Immediately upon
any redemption of the Rights, the right to exercise the Rights will terminate
and the only right of the holders of Rights will be to receive the Redemption
Price.


                                      C-3

<PAGE>

                  The terms of the Rights may be amended by the Board of
Directors of the Company without the consent of the holders of the Rights,
including an amendment to lower certain thresholds described above to not less
than the greater of (i) any percentage greater than the largest percentage of
the outstanding Common Shares then known to the Company to be beneficially owned
by any person or group of affiliated or associated persons (unless such person
or group is excluded from the effect of such reduction) and (ii) 10%, except
that from and after such time as any person becomes an Acquiring Person no such
amendment may adversely affect the interests of the holders of the Rights.

                  Until a Right is exercised, the holder of a Right will not, by
reason of being such a holder, have rights as a shareholder of the Company,
including, without limitation, the right to vote or to receive dividends.

                  Copies of the Rights Agreement and the Amendment have been
filed with the Securities and Exchange Commission as Exhibits to a Registration
Statement on Form 8-A. Copies of the Rights Agreement and the Amendment are
available free of charge from the Company. This summary description of the
Rights does not purport to be complete and is qualified in its entirety by
reference to the Rights Agreement and the Amendment which are hereby
incorporated herein by reference.











                                      C-4