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                       SECURITIES AND EXCHANGE COMMISSION
 
                             WASHINGTON, D.C. 20549
 
                                   FORM 10-K
 
(MARK ONE)
 
  /X/    ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF
         THE SECURITIES EXCHANGE ACT OF 1934 FOR THE YEAR
         ENDED DECEMBER 31, 1998
                                    OR
 
         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF
         THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION
         PERIOD FROM TO
  / /
 
                      Commission file number     033-18392
 
                                   AMERICORP
             (Exact name of registrant as specified in its charter)
 
<TABLE>
<S>                                                                                   <C>
State of California                                                                   77-0164985
(State or other jurisdiction of                                                       (I.R.S. Identification No.)
employee incorporation or organization)
 
304 East Main Street, Ventura, California 93001                                       (805) 658-6633
(Address of principal executive offices and Zip Code)                                 Registrant's telephone
                                                                                      number, including area code
</TABLE>
 
Securities registered pursuant to Section 12(b) of the Act: None
 
Securities registered pursuant to Section 12(g) of the Act: None
 
Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes [X] No [  ]
 
Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of the registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K [  ]. NOT APPLICABLE
 
Items 1, 6, 7, 7A, 8 and 14 of this Report are subject to completion pursuant to
Rule 12b-25.
 
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<PAGE>
                              INDEX TO FORM 10-KSB
 
PART I
 
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<CAPTION>
                                                                                                       PAGE
                                                                                                      -------
<S>                                <C>                                                                <C>
Item 1.                            Business                                                               3
 
Item 2.                            Properties                                                            13
 
Item 3.                            Legal Proceedings                                                     13
 
Item 4.                            Submission of Matters to a Vote of Security Holders                   14
 
PART II
 
Item 5.                            Market for Common Equity and Related Stockholders Matters             15
 
Item 6.                            Selected Financial Data                                               16
 
Item 7.                            Management's Discussion and Analysis of Financial Condition and       16
                                     Results of Operations
 
Item 7A                            Quantitative and Qualitative Disclosure About Market Risk             16
 
Item 8.                            Financial Statements                                                  16
 
Item 9.                            Changes and Disagreements with Accountants on Accounting and          16
                                     Financial Disclosure
 
PART III
 
Item 10.                           Directors and Executive Officers of the Registrant                    17
 
Item 11.                           Executive Compensation                                                19
 
Item 12.                           Security Ownership of Certain Beneficial Owners and Management        22
 
Item 13.                           Certain Relationships and Related Transactions                        23
 
Item 14.                           Exhibits and Reports on Form 8-K                                      23
</TABLE>
 
                                       2
<PAGE>
                                     PART I
 
ITEM 1. BUSINESS
 
GENERAL
 
    Americorp ("Americorp" or the "Company") is a California corporation
organized to act as the bank holding company for American Commercial Bank ("ACB"
or the "Bank"). In 1987, Americorp acquired all of the outstanding common stock
of ACB in a holding company formation transaction. Other than holding the shares
of ACB, Americorp conducts no significant activities, although it is authorized,
with the prior approval of the Board of Governors of the Federal Reserve System
(the "Federal Reserve Board"), Americorp's principal regulator, to engage in a
variety of activities which are deemed closely related to the business of
banking. At December 31, 1998, Americorp had approximately $    million in
consolidated assets, $    million in consolidated net loans, $    million in
consolidated deposits, and $    million in consolidated stockholders' equity
after giving effect to the transaction with Channel Islands Bank described
below.
 
    ACB was licensed by the California Department of Financial Institutions (the
"DFI") and commenced operation in September 1973 as a California state bank. As
a California state bank, ACB is subject to primary supervision, examination and
regulation by the DFI and the Federal Deposit Insurance Corporation (the
"FDIC"). ACB is also subject to certain other federal laws and regulations. The
deposits of ACB are insured by the FDIC up to the applicable limits thereof. ACB
is not a member of the Federal Reserve System.
 
TRANSACTION WITH CHANNEL ISLANDS BANK
 
    Americorp and ACB entered into an Agreement to Merge and Plan of
Reorganization dated July 7, 1998 and amended on September 17, 1998 (the "Merger
Agreement") with Channel Islands Bank, headquartered in Oxnard, California
("CIB").
 
    The Merger Agreement provided for, among other things, (i) the merger of CIB
with and into ACB with ACB as the surviving bank, and (ii) the shareholders of
CIB becoming shareholders of Americorp in accordance with the exchange ratio set
forth in the Merger Agreement. The merger was consummated on December 31, 1998.
 
    The merger with CIB was intended to be a so-called "Merger of Equals"
whereby comparatively similar sized financial institutions and their respective
managements, boards of directors, shareholder groups and businesses are combined
to create an institution which may provide for, among other things, increased
synergies, expended products and markets, higher lending limits and a reduction
of overall overhead costs, including a reduction in duplicate positions and
employee benefits. Such mergers may also enhance the liquidity of a
shareholder's investment and may provide the combined entity with easier access
to the capital markets. "Mergers of Equals" provide the same types of risk
associated with combining any two entities, including (i) the disadvantages of
being part of a larger entity, including reduced voting power and the potential
for decreased customer service; (ii) the integration of the different corporate
cultures of the entities will divert the combined entities' management time from
other activities and (iii) the proposed changes to policies and procedures of
the combined entity may not prove to be successful to the customers of the
combined entity. "Mergers of Equals" also generally provide, among other less
favorable aspects, a smaller premium on their investment to the non-surviving
institutions' shareholders than would be anticipated in an actual sale of
control, less liquidity to such shareholders for their investment than if the
non-surviving institution had been acquired by a larger acquiror as well as the
difficulties associated with combining the human resources and cultural
differences of two similar sized institutions.
 
    At the consummation of the merger, CIB had approximately $    million in
total assets, approximately $    million in total loans, approximately $
million in total deposits and approximately $    million in total stockholders'
equity.
 
                                       3
<PAGE>
    The exchange ratio used in the merger was .7282 shares of Americorp Common
Stock for each share of CIB outstanding. Americorp issued a total of 405,505
shares of Common Stock in connection with the transaction.
 
    The merger was intended to be tax free at the corporate and shareholders
levels.
 
    The merger was accounted for as a "pooling of interest" and the financial
statement included in Item 8 hereof have been prepared in accordance with such
determination. See footnote   to such financial statements. ALL INFORMATION
CONCERNING AMERICORP AND ACB HEREIN REFLECTS THE CONSUMMATION OF THE MERGER.
 
BANKING SERVICES
 
    ACB is engaged in substantially all of the business operations customarily
conducted by independent California state bank. ACB maintains three full
service-banking offices in the city of Ventura, two full service offices in the
city of Oxnard and two full service offices in the city of Camarillo. ACB's
banking services include the acceptance of checking and savings deposits, and
the making of commercial, SBA, real estate, personal, automobile and other
installment loans. ACB also offers traveler's checks, notary public and other
customary bank services to its customers. While ACB does offer credit cards to
its customers, other financial institutions issue the cards. Trust services are
not offered by ACB.
 
    ACB's deposits are attracted primarily from individuals and small and
medium-sized business-related sources. ACB also attracts deposits from several
local agencies. In connection with municipal deposits, ACB is generally required
to pledge securities to secure such deposits, except for the first $100,000 of
such deposits which are insured by the FDIC.
 
    As of December 31, 1998, ACB had approximately     deposit accounts,
representing approximately     non-interest bearing (demand) accounts with
balances totaling approximately $    for an average balance per account of
approximately $    ;     savings, interest-bearing demand and money market
accounts with balances totaling approximately $    for an average balance per
account of approximately $    and     time certificate of deposit accounts with
balances totaling approximately $    for an average balance per account of
approximately $    .
 
    Americorp is engaged in lending activities to businesses and consumers
throughout the geographic area of Ventura County, California. ACB has
concentrations in commercial loans, real estate loans and installment loans. The
risks associated with these types of loans vary with the borrower, associated
type of industry and prevailing economic conditions.
 
    Business loans are extended to a variety of commercial borrowers. These
loans include revolving lines of credit, both secured and unsecured; equipment
financing and term loans on real estate. In general, business loans have a
higher degree of risk associated with changing economic cycles, product
obsolescence and management experience. ACB utilizes a loan policy manual which
sets standards for the accepted level of risk in the particular area under
consideration. Business loans are reviewed by experienced loan personnel
utilizing a secondary review and approval process which ultimately is overseen
by the Board of Directors. ACB typically obtains the guarantees of the borrowing
company's principal owners. Business lending risk is also mitigated by the
contracted services of an independent loan review company. Commercial loans
outstanding, as of December 31, 1998, totaled $    representing   % of the
portfolio.
 
    ACB also structures commercial loans secured by the real estate. These loans
also vary in risk depending primarily on business cycles. Commercial real estate
loans generally are amortized over a 20 year period with maturity dates of 5
years. ACB accepts properties whose appraised values provides a loan-to-value
ratio of 75% or less. Commercial loans outstanding, at December 31, 1998,
totaled $    , representing   % of the portfolio. ACB is not involved with any
residential tract housing construction and limits construction loans to either
pre-sold or contract homes with permanent financing arranged. Construction loans
total less than 3% of the total loan portfolio.
 
                                       4
<PAGE>
    ACB is also engaged in the brokering of single family first trust deeds to
other lenders.
 
    ACB also extends loans to consumers which include automobiles, installment,
recreational vehicles, equity lines of credit, bankcard and overdraft
protection. As of December 31, 1998, ACB had $    in installment loans
outstanding, representing   % of the portfolio. Home equity loans, primarily
secured by second deeds of trusts, totaled $    , representing   % of the
portfolio. Bankcard loans outstanding totaled $    and overdraft protection
totaled $    representing   % and   % respectively of the total portfolio.
During 1998, ACB sold its bankcard portfolio for a nominal premium. Consumer
loans are underwritten according to standards set in ACB's loan policy manual.
ACB utilizes Experian and Trans Union credit reporting agencies to obtain
current information on a consumer's payment history, monitors delinquency trends
regularly and sets reserves to mitigate risk in this area.
 
    The principal sources of ACB's revenues are (i) interest and fees on loans,
(ii) interest on investments, (iii) service charges on deposit accounts and
other charges and fees, and (iv) interest on federal funds sold (funds loaned on
short-term basis to other banks). For the period ended December 31, 1998, these
sources comprised   %,   %,   % and   %, respectively, of ACB's total operating
income.
 
    Virtually all of the consolidated net income of Americorp is generated by
ACB.
 
    ACB has not engaged in any material research activities relating to the
development of new services or the improvement of existing ACB services.
 
    There has been no significant change in the types of services offered by ACB
since its inception, except in connection with new types of accounts allowed by
statute or regulation in recent years. ACB has no present plans regarding "a new
line of business" requiring the investment of a material amount of total assets.
 
    Most of ACB's business originates from Ventura County and there is no
emphasis on foreign sources and application of funds. ACB's business, based upon
performance to date, does not appear to be seasonal. Except as described above,
a material portion of ACB's loans is not concentrated within a single industry
or group of related industries, nor is ACB dependent upon a single customer or
group of related customers for a material portion of its deposits. Management of
ACB is unaware of any material effect upon ACB's capital expenditures, earnings
or competitive position as a result of federal, state or local environmental
regulation.
 
    ACB holds no patents, licenses (other than licenses obtained from ACB
regulatory authorities), franchises or concessions.
 
EMPLOYEES
 
    As of December 31, 1998, ACB had a total of 95 full-time employees and 24
part-time employees. The management of ACB believes that its employee relations
are satisfactory.
 
COMPETITION
 
    Banking and financial services business in California generally, and in
ACB's market areas specifically, is highly competitive. The increasingly
competitive environment is a result primarily of changes in regulation, changes
in technology and product delivery systems, and the accelerating pace of
consolidation among financial services providers. ACB competes for loans and
deposits and customers for financial services with other commercial banks,
savings and loan associations, securities and brokerage companies, mortgage
companies, insurance companies, finance companies, money market funds, credit
unions, and other nonbank financial service providers. Many of these competitors
are much larger in total assets and capitalization, have greater access to
capital markets and offer a broader array of financial services than ACB. In
order to compete with the other financial services providers, ACB principally
relies upon local promotional activities, personal relationships established by
officers, directors and employees with its
 
                                       5
<PAGE>
customers, and specialized services tailored to meet its customers' needs. ACB
maintains seven full service-banking offices in Ventura County.
 
YEAR 2000 RISKS AND PREPAREDNESS
 
    Many existing computer programs use only two digits to identify a year in a
data field. These programs were designed and developed without considering the
impact of the upcoming change in the century. If not corrected, many computer
applications could fail or create erroneous results by or at the Year 2000 or
possibly earlier. In that the financial services business is highly dependent on
computer applications the Year 2000 issue affects the Company in a variety of
ways, including the following (i) the Company relies on computer systems in
almost all aspects of its business, including the processing of deposits, loans
and other services and products offered to customers, the failure of which in
connection with the Year 2000 could cause systemic disruptions and failures in
the products and services offered by the Company, (ii) other banks, clearing
houses and vendors whose products and services the Company uses are at risk of
systemic disruptions and potential failures in the event that such entities have
not adequately addressed their Year 2000 issues prior to the Year 2000, (iii)
the creditworthiness of borrowers of the Company might be diminished by
significant disruptions of their business as a result of their own or others'
failure to address adequately the Year 2000 issues prior to the Year 2000, and
(iv) federal banking agencies have issued interagency guidance on the
business-wide risk posed to financial institutions by the year 2000 problem
pursuant to which the federal banking agencies may take supervisory action
against financial institutions that fail to address appropriately Year 2000
issues prior to the Year 2000, including formal and informal enforcement
actions, denial of applications to the federal banking agencies, civil money
penalties and a reduction in the management component rating of the
institution's composite rating.
 
    In order to address the Year 2000 issues facing the Company, the Company's
Management has initiated a program to prepare the Company's computer systems and
applications for the Year 2000 (the "Year 2000 Plan"). The primary focus of the
Year 2000 Plan is to convert to the target systems identified and believed to be
Year 2000 compliant. The Company expects to incur internal staff costs as well
as consulting and other expenses related to infrastructure and facilities
enhancements necessary to prepare for conversion and Year 2000 system
preparations.
 
    As a part of the Year 2000 Plan, the Company is not only undertaking the
infrastructure and facilities enhancement and testing necessary to ensure that
the Company is adequately prepared for the Year 2000, but the Company is also
communicating with its vendors upon whose services the Company relies to ensure
Year 2000 compliance. Pursuant to the Year 2000 Plan, the Company substantially
completed testing of its mission-critical systems and the computer-related
interactive vendor systems by December 31, 1998 and expects to complete all
testing by June 1999. In addition, as part of the credit review process, the
Company is communicating with its major borrowers in an effort to ensure that
such borrowers have taken appropriate steps to address their Year 2000 issues
and will not be materially affected by any Year 2000 problems. The Company is
communicating with its deposit customers as well. The Company is also preparing
contingency plans to protect the Company in the event that the Company is unable
to attain Year 2000 compliance in certain applications according to the Year
2000 Plan.
 
    The Company has established a working committee comprised of Senior and
Middle Management to plan for and monitor the Company's compliance with Year
2000 issues. This committee has developed a comprehensive policy setting forth
priorities and a timetable for the Bank to follow in this process.
 
    The Company has developed a contingency plan that identifies the mission
critical processes and service providers. An alternative provider or process has
been identified for each mission critical vendor. In addition, on the assumption
that the original or alternative process fails at the point of processing in the
Year 2000, contingency plans are being designed that will provide minimum levels
of service or outputs until the failed system can be repaired or replaced. Most
of these contingency plans are manual effort systems. Test results to-date
indicate that the original system for each mission critical system should meet
 
                                       6
<PAGE>
the demands of processing in the Year 2000. As a reasonable worst case, the
manual systems designed should provide the minimum levels of service for the
time required to repair or replace failed systems. However, in the case of
failure, the ultimate impact on financial operations is not known, nor is it
known what impact a regional or nationwide power failure or communications
breakdown would have on the financial performance of the Company.
 
    The Company has created a budget specific to Year 2000 readiness. The budget
is comprised of the following components: (1) Consulting assistance for testing,
(2) Auditing, and (3) Operating system and network upgrades. These components
are budgeted at $300,000. As of December 31, 1998, $154,782, or 52% has been
spent. Senior Management reviews the budget from time to time as the Year 2000
Plan is implemented. There is no assurance that additional amounts will not be
added to the amounts already budgeted for Year 2000 expenditures. With respect
to components number (1) and (2), it should be noted that the Company has
engaged the services of three consulting firms that have or are currently
providing audit review of the effectiveness of the Year 2000 Plan and
technological assistance in preparing for and conducting the Company's testing
plan. Some of these fees, estimated to be approximately $7,500 combined, have
yet to be expensed.
 
    In addition, the Company has dedicated significant human resources to the
Year 2000 Plan. This includes the salaries and benefits of personnel devoting
significant time to the plan. As of December 31, 1998, the Company had expended
over $120,000 in "man-hours" to the project, equivalent to 100 work weeks. In
addition, expenditures have been made in the areas of advertising and public
relations, customer and employee awareness programs and more.
 
    In April of 1998, the Company initiated a credit risk assessment program,
with loan officers completing a Year 2000 questionnaire for all new and renewed
credits in amounts over $100,000. These questionnaires were designed to provide
the Company's management with information by which it could evaluate the
borrower's awareness of and sensitivity to Year 2000 risk. Questionnaires are
reviewed and discussed at weekly Officer Loan Committee meetings and are further
reviewed by Credit Administration and a Senior Lender to ascertain Year 2000
risk associated with the credit. As a result of this review, $
has been allocated to the Company's loan loss provision. In addition, legal
language addressing Year 2000 issues is included in significant commitment
letters and loan documentation for certain borrowers. Finally, on loan
participations purchased, the Company requires assurances from the lead lender
that it has obtained a Year 2000 questionnaire from the borrower and also that
the lead lender is satisfactorily progressing toward Year 2000 compliance.
 
    Although the Company believes that its Year 2000 Plan and other steps being
taken are adequate to ensure that it will not be materially affected by the Year
2000 problem, there can be no assurance that the Year 2000 Plan and the
Company's other Year 2000 remedial and contingency plans will fully protect the
Company from the risks associated with the Year 2000. The analysis of, and
preparation for, the Year 2000 and related problems necessarily rely on a
variety of assumptions about future events and there can be no assurance that
the Company's Management has accurately predicted such future events or that the
remedial and contingency plans of the Company will adequately address such
future events. In the event that the business of the Company, of vendors of the
Company or of customers of the Company is disrupted as a result of the Year 2000
problem, such disruption could have a material adverse effect on the Company.
 
EFFECT OF GOVERNMENTAL POLICIES AND RECENT LEGISLATION
 
    Banking is a business that depends on rate differentials. In general, the
difference between the interest rate paid by the Bank on its deposits and its
other borrowings and the interest rate received by the Bank on loans extended to
its customers and securities held in the Bank's portfolio comprise the major
portion of the Bank's earnings. These rates are highly sensitive to many factors
that are beyond the control of the Bank. Accordingly, the earnings and growth of
the Bank are subject to the influence of domestic and foreign economic
conditions, including inflation, recession and unemployment.
 
                                       7
<PAGE>
    The commercial banking business is not only affected by general economic
conditions but is also influenced by the monetary and fiscal policies of the
federal government and the policies of regulatory agencies, particularly the
Federal Reserve Board. The Federal Reserve Board implements national monetary
policies (with objectives such as curbing inflation and combating recession) by
its open-market operations in United States Government securities, by adjusting
the required level of reserves for financial institutions subject to its reserve
requirements and by varying the discount rates applicable to borrowings by
depository institutions. The actions of the Federal Reserve Board in these areas
influence the growth of bank loans, investments and deposits and also affect
interest rates charged on loans and paid on deposits. The nature and impact of
any future changes in monetary policies cannot be predicted.
 
    From time to time, legislation is enacted which has the effect of increasing
the cost of doing business, limiting or expanding permissible activities or
affecting the competitive balance between banks and other financial
institutions. Proposals to change the laws and regulations governing the
operations and taxation of banks, bank holding companies and other financial
institutions are frequently made in Congress, in the California legislature and
before various bank regulatory and other professional agencies. For example,
legislation has been introduced in Congress that would repeal the current
statutory restrictions on affiliations between commercial banks and securities
firms. See "Financial Modernization Legislation."
 
SUPERVISION AND REGULATION
 
    The Company and the Bank are extensively regulated under both federal and
state law. Set forth below is a summary description of certain laws which relate
to the regulation of the Company and the Bank. The description does not purport
to be complete and is qualified in its entirety by reference to the applicable
laws and regulations.
 
    AMERICORP
 
    The Company is a bank holding company within the meaning of the Bank Holding
Company Act of 1956, as amended (the "Bank Holding Company Act"), and is
registered as such with, and subject to the supervision of, the Federal Reserve
Board. The Company is required to file with the Federal Reserve Board quarterly
and annual reports and such additional information as the Federal Reserve Board
may require pursuant to the Bank Holding Company Act. The Federal Reserve Board
may conduct examinations of bank holding companies and their subsidiaries.
 
    The Company is required to obtain the approval of the Federal Reserve Board
before it may acquire all or substantially all of the assets of any bank, or
ownership or control of the voting shares of any bank if, after giving effect to
such acquisition of shares, the Company would own or control more than 5% of the
voting shares of such bank. Prior approval of the Federal Reserve Board is also
required for the merger or consolidation of the Company and another bank holding
company.
 
    The Company is prohibited by the Bank Holding Company Act, except in certain
statutorily prescribed instances, from acquiring direct or indirect ownership or
control of more than 5% of the outstanding voting shares of any company that is
not a bank or bank holding company and from engaging , directly or indirectly,
in activities other than those of banking, managing or controlling banks or
furnishing services to its subsidiaries. However, the Company may, subject to
the prior approval of the Federal Reserve Board, engage in any, or acquire
shares of companies engaged in, activities that are deemed by the Federal
Reserve Board to be so closely related to banking or managing or controlling
banks as to be a proper incident thereto.
 
                                       8
<PAGE>
    The Federal Reserve Board may require that the Company terminate an activity
or terminate control of or liquidate or divest subsidiaries or affiliates when
the Federal Reserve Board determines that the activity or the control or the
subsidiary or affiliates constitutes a significant risk to the financial safety,
soundness or stability of any of its banking subsidiaries. The Federal Reserve
Board also has the authority to regulate provisions of certain bank holding
company debt, including authority to impose interest ceilings and reserve
requirements on such debt. Under certain circumstances, the Company must file
written notice and obtain approval from the Federal Reserve Board prior to
purchasing or redeeming its equity securities.
 
    Under the Federal Reserve Board's regulations, a bank holding company is
required to serve as a source of financial and managerial strength to its
subsidiary banks and may not conduct its operations in an unsafe and unsound
manner. In addition, it is the Federal Reserve Board's policy that in serving as
a source of strength to its subsidiary banks, a bank holding company should
stand ready to use available resources to provide adequate capital funds to its
subsidiary banks during periods of financial stress or adversity and should
maintain the financial flexibility and capital-raising capacity to obtain
additional resources for assisting its subsidiary banks. A bank holding
company's failure to meet its obligations to serve as a source of strength to
its subsidiary banks will generally be considered by the Federal Reserve Board
to be an unsafe and unsound banking practice or a violation of the Federal
Reserve Board's regulations or both.
 
    The Company is subject to the periodic reporting requirements of Section
15(d) of the Securities Exchange Act of 1934, as amended, and files certain
reports pursuant to such Act with the Securities and Exchange Commission (the
"SEC").
 
    ACB
 
    The Bank is chartered under the laws of the State of California and its
deposits are insured by the FDIC to the extent provided by law. The Bank is
subject to the supervision of, and is regularly examined by, the DFI and the
FDIC. Such supervision and regulation include comprehensive reviews of all major
aspects of the Banks business and condition.
 
    Various requirements and restrictions under the laws of the United States
and the State of California affect the operations of the Bank. Federal and
California statutes relate to many aspects of the Banks operations, including
reserves against deposits, interest rates payable on deposits, loans,
investments, mergers and acquisitions, borrowings, dividends and locations of
branch offices. Further, the Bank is required to maintain certain levels of
capital.
 
CAPITAL STANDARDS
 
    The Federal Reserve Board and the FDIC have adopted risk-based minimum
capital guidelines intended to provide a measure of capital that reflects the
degree of risk associated with a banking organization's operations for both
transactions reported on the balance sheet as assets and transactions, such as
letters of credit and recourse arrangements, which are recorded as off balance
sheet items. Under these guidelines, nominal dollar amounts of assets and credit
equivalent amounts of off balance sheet items are multiplied by one of several
risk adjustment percentages, which range from 0% for assets with low credit
risk, such as certain U.S. Treasury securities, to 100% for assets with
relatively high credit risk, such as business loans.
 
    A banking organization's risk-based capital ratios are obtained by dividing
its qualifying capital by its total risk adjusted assets. The regulators measure
risk-adjusted assets, which includes off balance sheet
items, against both total qualifying capital (the sum of Tier 1 capital and
limited amounts of Tier 2 capital) and Tier 1 capital. Tier 1 capital consists
primarily of common stock, retained earnings, noncumulative perpetual preferred
stock (cumulative perpetual preferred stock for bank holding companies) and
minority interests in certain subsidiaries, less most intangible assets. Tier 2
capital may consist of a limited amount of the allowance for possible loan and
lease losses, cumulative preferred stock, long term preferred stock,
 
                                       9
<PAGE>
eligible term subordinated debt and certain other instruments with some
characteristics of equity. The inclusion of elements of Tier 2 capital is
subject to certain other requirements and limitations of the federal banking
agencies. The federal banking agencies require a minimum ratio of qualifying
total capital to risk-adjusted assets of 8% and a minimum ratio of Tier 1
capital to risk-adjusted assets of 4%.
 
    In addition to the risked-based guidelines, federal banking regulators
require banking organizations to maintain a minimum amount of Tier 1 capital to
total assets, referred to as the leverage ratio. For a banking organization
rated in the highest of the five categories used by regulators to rate banking
organizations, the minimum leverage ratio of Tier 1 capital to total assets is
3%. For all banking organizations not rated in the highest category, the minimum
leverage ratio must be at least 100 to 200 basis points above the 3% minimum, or
4% to 5%. In addition to these uniform risk-based capital guidelines and
leverage ratios that apply across the industry, the regulators have the
discretion to set individual minimum capital requirements for specific
institutions at rates significantly above the minimum guidelines and ratios.
 
    Future changes in regulations or practices could further reduce the amount
of capital recognized for purposes of capital adequacy. Such a change could
affect the ability of the Bank to grow and could restrict the amount of profits,
if any, available for the payment of dividends.
 
    The following table presents the amounts of regulatory capital and the
capital ratios for the Bank, compared to its minimum regulatory capital
requirements as of December 31, 1998.
 
<TABLE>
<CAPTION>
                                                                                DECEMBER 31, 1998
                                                                          ------------------------------
                                                                                        MINIMUM CAPITAL
                                                                            ACTUAL        REQUIREMENT
                                                                          -----------  -----------------
<S>                                                                       <C>          <C>
Leverage ratio..........................................................            %            4.0%
Tier 1 risk-based ratio.................................................                         4.0
Total risk-based ratio..................................................                         8.0
</TABLE>
 
    Under applicable regulatory guidelines, the Company and the Bank were
considered "Well Capitalized" at December 31, 1998.
 
    On January 1, 1998 new legislation became effective which, among other
things, gave the power to the DFI to take possession of the business and
properties of a bank in the event that the tangible shareholders' equity of the
bank is less than the greater of (i) 3% of the banks total assets or (ii)
$1,000,000.
 
PROMPT CORRECTIVE ACTION AND OTHER ENFORCEMENT MECHANISMS
 
    Federal law requires each federal banking agency to take prompt corrective
action to resolve the problems of insured depository institutions, including but
not limited to those that fall below one or more prescribed minimum capital
ratios. The law required each federal banking agency to promulgate regulations
defining the following five categories in which an insured depository
institution will be placed, based on the level of its capital ratios: well
capitalized, adequately capitalized, undercapitalized, significantly
undercapitalized and critically undercapitalized.
 
                                       10
<PAGE>
    An insured depository institution generally will be classified in the
following categories based on capital measures indicated below:
 
<TABLE>
<S>                                        <C>
"Well capitalized"                         "Adequately capitalized"
Total risk-based capital of 10%;           Total risk-based capital of 8%;
Tier 1 risk-based capital of 6%; and       Tier 1 risk-based capital of 4%; and
Leverage ratio of 5%.                      Leverage ratio of 4%.
 
"Undercapitalized"                         "Significantly undercapitalized"
Total risk-based capital less than 8%;     Total risk-based capital less than 6%;
Tier 1 risk-based capital less than 4%;    Tier 1 risk-based capital less than 3%;
  or                                        or
Leverage ratio less than 4%.               Leverage ratio less than 3%.
 
"Critically undercapitalized"
Tangible equity to total assets less than
  2%.
</TABLE>
 
    An institution that, based upon its capital levels, is classified as "well
capitalized," "adequately capitalized" or "undercapitalized" may be treated as
though it were in the next lower capital category if the appropriate federal
banking agency, after notice and opportunity for hearing, determines that an
unsafe or unsound condition or an unsafe or unsound practice warrants such
treatment. At each successive lower capital category, an insured depository
institution is subject to more restrictions. The federal banking agencies,
however, may not treat an institution as "critically undercapitalized" unless
its capital ratio actually warrants such treatment.
 
    The law prohibits insured depository institutions from paying management
fees to any controlling persons or, with certain limited exceptions, making
capital distributions if after such transaction the institution would be
undercapitalized. If an insured depository institution is undercapitalized, it
will be closely monitored by the appropriate federal banking agency, subject to
asset growth restrictions and required to obtain prior regulatory approval for
acquisitions, branching and engaging in new lines of business. Any
undercapitalized depository institution must submit an acceptable capital
restoration plan to the appropriate federal banking agency 45 days after
becoming undercapitalized. The appropriate federal banking agency cannot accept
a capital plan unless, among other things, it determines that the plan (i)
specifies the steps the institution will take to become adequately capitalized,
(ii) is based on realistic assumptions and (iii) is likely to succeed in
restoring the depository institution's capital. In addition, each company
controlling an undercapitalized depository institution must guarantee that the
institution will comply with the capital plan until the depository institution
has been adequately capitalized on an average basis during each of four
consecutive calendar quarters and must otherwise provide adequate assurances of
performance. The aggregate liability of such guarantee is limited to the lesser
of (a) an amount equal to 5% of the depository institution's total assets at the
time the institution became undercapitalized or (b) the amount which is
necessary to bring the institution into compliance with all capital standards
applicable to such institution as of the time the institution fails to comply
with its capital restoration plan. Finally, the appropriate federal banking
agency may impose any of the additional restrictions or sanctions that it may
impose on significantly undercapitalized institutions if it determines that such
action will further the purpose of the prompt correction action provisions.
 
    An insured depository institution that is significantly undercapitalized, or
is undercapitalized and fails to submit, or in a material respect to implement,
an acceptable capital restoration plan, is subject to additional restrictions
and sanctions. These include, among other things: (i) a forced sale of voting
shares to raise capital or, if grounds exist for appointment of a receiver or
conservator, a forced merger; (ii) restrictions on transactions with affiliates;
(iii) further limitations on interest rates paid on deposits; (iv) further
restrictions on growth or required shrinkage; (v) modification or termination of
specified activities; (vi) replacement of directors or senior executive
officers; (vii) prohibitions on the receipt of
 
                                       11
<PAGE>
deposits from correspondent institutions; (viii) restrictions on capital
distributions by the holding companies of such institutions; (ix) required
divestiture of subsidiaries by the institution; or (x) other restrictions as
determined by the appropriate federal banking agency. Although the appropriate
federal banking agency has discretion to determine which of the foregoing
restrictions or sanctions it will seek to impose, it is required to force a sale
of voting shares or merger, impose restrictions on affiliate transactions and
impose restrictions on rates paid on deposits unless it determines that such
actions would not further the purpose of the prompt corrective action
provisions. In addition, without the prior written approval of the appropriate
federal banking agency, a significantly undercapitalized institution may not pay
any bonus to its senior executive officers or provide compensation to any of
them at a rate that exceeds such officer's average rate of base compensation
during the 12 calendar months preceding the month in which the institution
became undercapitalized.
 
    Further restrictions and sanctions are required to be imposed on insured
depository institutions that are critically undercapitalized. For example, a
critically undercapitalized institution generally would be prohibited from
engaging in any material transaction other than in the ordinary course of
business without prior regulatory approval and could not, with certain
exceptions, make any payment of principal or interest on its subordinated debt
beginning 60 days after becoming critically undercapitalized. Most importantly,
however, except under limited circumstances, the appropriate federal banking
agency, not later than 90 days after an insured depository institution becomes
critically undercapitalized, is required to appoint a conservator or receiver
for the institution. The board of directors of an insured depository institution
would not be liable to the institution's shareholders or creditors for
consenting in good faith to the appointment of a receiver or conservator or to
an acquisition or merger as required by the regulator.
 
    In addition to measures taken under the prompt corrective action provisions,
commercial banking organizations may be subject to potential enforcement actions
by the federal regulators for unsafe or unsound practices in conducting their
businesses or for violations of any law, rule, regulation or any condition
imposed in writing by the agency or any written agreement with the agency.
Enforcement actions may include the imposition of a conservator or receiver, the
issuance of a cease and desist order that can be judicially enforced, the
termination of insurance of deposits (in the case of a depository institution),
the imposition of civil money penalties, the issuance of directives to increase
capital, the issuance of formal and informal agreements, the issuance of removal
and prohibition orders against institution-affiliated parties and the
enforcement of such actions through injunctions or restraining orders based upon
a judicial determination that the agency would be harmed if such equitable
relief was not granted.
 
PREMIUMS FOR DEPOSIT INSURANCE
 
    All deposits of the Bank are insured by the FDIC through the Bank Insurance
Fund ("BIF") which are subject to FDIC insurance assessment. The amount of FDIC
assessment paid by individual insured depository institutions is based upon
their relative risk as measured by regulatory capital ratios and certain other
factors. During 1995, the FDIC significantly reduced premium rates assessed on
deposits insured by the BIF. As a result of its "Well Capitalized" status, the
Bank currently pays approximately $6,900 per year.
 
FINANCIAL MODERNIZATION LEGISLATION
 
    Various proposals to adopt comprehensive financial modernization legislation
have been introduced in Congress which include, among other things, elimination
of the federal thrift charter, creation of a uniform financial institutions
charter, expansion of bank powers, and integration of banking, commerce,
securities activities and insurance. In May 1998, the House passed legislation
that would have overhauled the financial services industry and would have, among
other things, allowed mergers among banking, securities and insurance firms.
Congress adjourned for 1998 without the passage of similar legislation by the
Senate. Similar legislation has already been introduced in both houses of
Congress in the current session. It is currently impossible to predict whether
and in what form financial reform legislation will be
 
                                       12
<PAGE>
passed in 1999 or in the future or what the impact of such legislation might be
on the Company, its financial condition and business as well as its results of
operations.
 
COMMUNITY REINVESTMENT ACT
 
    The Bank is subject to certain fair lending requirements and reporting
obligations involving home mortgage lending operations and Community
Reinvestment Act ("CRA") activities. The CRA generally requires the federal
banking agencies to evaluate the record of a financial institution in meeting
the credit needs of their local communities, including low and moderate income
neighborhoods. In addition to substantial penalties and corrective measures that
may be required for a violation of certain fair lending laws, the federal
banking agencies may take compliance with such laws and CRA into account when
regulating and supervising other activities.
 
    In connection with its assessment of CRA performance, the appropriate bank
regulatory agency assigns a rating of "outstanding." "satisfactory," "needs to
improve" or "substantial noncompliance." At its last examination by the FDIC,
the Bank received a CRA rating of "Satisfactory."
 
ACCOUNTING CHANGES
 
    From time to time the Financial Accounting Standards Board ("FASB") issues
pronouncements which govern the accounting treatment for the Company's financial
statements. For a description of the recent pronouncements applicable to the
Company (see the Notes to the Financial Statements included in Item 8 of this
Report). The FASB recently proposed for comment a change in the accounting rules
relating to mergers and acquisitions. Specifically, the "pooling method" of
accounting for mergers would be eliminated. Financial institutions often prefer
to account for mergers using this method and many of the mergers in the
financial institutions industry in the last several years have been accounted
for using the pooling method. The impact of such accounting change, if adopted,
upon mergers and acquisitions involving financial institutions and upon the
Company, its acquisition of CIB and the value of the Company's Common Stock can
not presently be predicted.
 
POTENTIAL ENFORCEMENT ACTIONS
 
    Commercial banking organizations, such as the Company and the Bank, may be
subject to potential enforcement actions by the Federal Reserve Board, the DFI
and the FDIC for unsafe or unsound practices in conducting their businesses or
for violations of any law, rule, regulation or any condition imposed in writing
by the agency or any written agreement with the agency. Enforcement actions may
include the imposition of a conservator or receiver, the issuance of a cease and
desist order that can be judicially enforced, the termination of insurance of
deposits (in the case of a depository institution), the imposition of civil
money penalties, the issuance of directives to increase capital, the issuance of
formal and informal agreements, the issuance of removal and prohibition orders
against institution-affiliated parties and the enforcement of such actions
through injunctions or restraining orders based upon a judicial determination
that the agency would be harmed if such equitable relief was not granted.
 
ITEM 2. PROPERTIES
 
    All ACB's offices are leased. See Note   to the Americorp Financial
Statements contained in Item 8 of this Report for certain additional information
concerning the amount of ACB's lease commitments.
 
ITEM 3. LEGAL PROCEEDINGS
 
    The Bank is, from time to time, subject to various pending and threatened
legal actions which arise out of the normal course of its business. Neither the
Company nor the Bank is a party to any pending legal or administrative
proceedings (other than ordinary routine litigation incidental to the Company's
or the Bank's business) and no such proceedings are known to be contemplated.
 
                                       13
<PAGE>
    There are no material proceedings adverse to the Company or the Bank to
which any director, officer, affiliate of the Company or 5 % shareholder of the
Company or the Bank, or any associate of any such director, officer, affiliate
or 5% shareholder of the Company or Bank is a party, and none of the above
persons has a material interest adverse to the Company or the Bank.
 
ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS
 
    On December 15, 1998, Americorp held a special meeting of its shareholders
in connection with a shareholder vote on the merger with CIB and on a new stock
option plan for Americorp. In connection with the merger with CIB, there were
418,092 shares voted in favor of the merger, 1,200 shares voted against and
2,036 shares abstained. In connection with the stock option plan, 403,837 shares
voted in favor of the plan, 12,931 shares voted against and 4,560 shares
abstained.
 
                                       14
<PAGE>
                                    PART II
 
ITEM 5. MARKET FOR COMMON EQUITY AND RELATED STOCKHOLDER MATTERS
 
MARKET INFORMATION
 
    Americorp Common Stock is not listed on any stock exchange or with Nasdaq.
Trading in the Stock has not been extensive and such trades which have occurred
would not constitute an active trading market.
 
    The management of Americorp is aware of one securities dealer who maintains
an inventory and makes a market in Americorp Common Stock - Maguire Investments,
Santa Maria, California. The following quarterly summary of market activity is
furnished by Maguire Investments. These quotes do not necessarily include retail
markups, markdowns or commissions and may not necessarily represent actual
transactions. Additionally, there may have been transactions at prices other
than those shown below:
 
<TABLE>
<CAPTION>
QUARTER                                                                           BID       ASKED
-----------------------------------------------------------------------------  ---------  ---------
<S>                                                                            <C>        <C>
First '96....................................................................      27.00      28.00
Second '96...................................................................      27.00      28.00
Third '96....................................................................      28.00      29.00
Fourth '96...................................................................      28.00      29.00
First '97....................................................................      28.00      29.00
Second '97...................................................................      28.00      29.00
Third '97....................................................................      28.50      29.50
Fourth '97...................................................................      31.00      32.00
First '98....................................................................      31.00      32.00
Second '98...................................................................      31.00      32.00
Third '98....................................................................      36.00      37.00
Fourth '98...................................................................      37.00      38.00
</TABLE>
 
HOLDERS
 
    As of February 1, 1999, there were approximately 419 holders of Americorp
Common Stock. There are no other classes of equity outstanding.
 
DIVIDENDS
 
    The Company is a legal entity separate and distinct from the Bank. The
Company's shareholders are entitled to receive dividends when and as declared by
its Board of Directors, out of funds legally available therefor, subject to the
restrictions set forth in the California General Corporation Law (the
"Corporation Law"). The Corporation Law provides that a corporation may make a
distribution to its shareholders if the corporation's retained earnings equal at
least the amount of the proposed distribution. The Corporation Law also provides
that, in the event that sufficient retained earnings are not available for the
proposed distribution, a corporation may nevertheless make a distribution to its
shareholders if it meets two conditions, which generally stated are as follows:
(i) the corporation's assets equal at least 1-1/4 times its liabilities, and
(ii) the corporation's current assets equal at least its current liabilities or,
if the average of the corporation's earnings before taxes on income and before
interest expenses for the two preceding fiscal years was less than the average
of the corporation's interest expenses for such fiscal years, then the
corporation's current assets must equal at least 1-1/4 times its current
liabilities.
 
    The ability of the Company to pay a cash dividend depends largely on the
Bank's ability to pay a cash dividend to the Company. The payment of cash
dividends by the Bank is subject to restrictions set forth in the California
Financial Code (the "Financial Code"). The Financial Code provides that a bank
may not make a cash distribution to its shareholders in excess of the lesser of
(a) the bank's retained earnings; or (b) the bank's net income for its last
three fiscal years, less the amount of any distributions made by the
 
                                       15
<PAGE>
bank or by any majority-owned subsidiary of the bank to the shareholders of the
bank during such period. However, a bank may, with the approval of the DFI, make
a distribution to its shareholders in an amount not exceeding the greater of (x)
its retained earnings; (y) its net income for its last fiscal year; or (z) its
net income for its current fiscal year. In the event that the DFI determines
that the shareholders' equity of a bank is inadequate or that the making of a
distribution by the bank would be unsafe or unsound, the DFI may order the bank
to refrain from making a proposed distribution. The FDIC may also restrict the
payment of dividends if such payment would be deemed unsafe or unsound or if
after the payment of such dividends, the Bank would be included in one of the
"undercapitalized" categories for capital adequacy purposes pursuant to federal
law. (See, "Item 1 - Description of Business - Prompt Corrective Action and
Other Enforcement Mechanisms.") Additionally, while the Federal Reserve Board
has no general restriction with respect to the payment of cash dividends by an
adequately capitalized bank to its parent holding company, the Federal Reserve
Board might, under certain circumstances, place restrictions on the ability of a
particular bank to pay dividends based upon peer group averages and the
performance and maturity of the particular bank, or object to management fees to
be paid by a subsidiary bank to its holding company on the basis that such fees
cannot be supported by the value of the services rendered or are not the result
of an arm's length transaction.
 
    Under these provisions and considering minimum regulatory capital
requirements, the amount available for distribution from the Bank to the Company
was approximately $    at December 31, 1998.
 
    Americorp has paid 61 consecutive quarterly cash dividends to its
shareholders. Americorp is currently paying quarterly cash dividends of $0.21
per share and has paid at such rate since July 1995.
 
    The dividend policy of Americorp is not expected to be changed as a result
of the merger with CIB; however, no assurances can be given that such policy may
not change. Moreover, declarations or payments of dividends by the Board of
Directors of Americorp after the merger with CIB will depend upon a number of
factors, including capital requirements, regulatory limitations (as discussed
above), Americorp's and ACB's financial condition and results of operations, tax
considerations and general economic conditions. No assurance can be given that
any dividends will be declared or, if declared, what the amount of dividends or
their type (cash, stock or both) will be or whether such dividends, once
declared, will continue.
 
ITEM 6. SELECTED FINANCIAL DATA
 
    Subject to completion pursuant to Rule 12b-25.
 
ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS
 
    Subject to completion pursuant to Rule 12b-25.
 
ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK
 
    Subject to completion pursuant to Rule 12b-25.
 
ITEM 8. FINANCIAL STATEMENTS
 
    Subject to completion pursuant to Rule 12b-25.
 
ITEM 9. CHANGES AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL
        DISCLOSURE
 
    Information in response to this Item is set forth in Americorp's Report on
Form 8-K filed with the SEC on December 4, 1998 which by this reference is
incorporated herein.
 
                                       16
<PAGE>
                                    PART III
 
ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF REGISTRANT
 
    The following table sets forth information on the current members of the
Boards of Directors of Americorp and ACB after the merger with CIB.
 
<TABLE>
<CAPTION>
                                                                                                            YEAR
                                                                                                            FIRST
                                                                                                            ELECTED
                                                                                                            OR
NAME                               AGE   BUSINESS EXPERIENCE FOR PAST FIVE YEARS                            APPOINTED
---------------------------------  ---   -----------------------------------------------------------------  -------
<S>                                <C>   <C>                                                                <C>
Michael T. Hribar................  51    Certified Public Accountant                                         1998
 
Allen W. Jue.....................  63    Chairman of the Board (since 1994); Owner, Jue's Market             1973
 
Robert J. Lagomarsino............  72    VP Lagomarsino's (family business); U.S. Congress, 1974-93          1993
 
Gerald J. Lukiewski..............  45    Banker, President of ACB 3/98 to present; S.V.P. Chief Credit       1998
                                           Officer 7/97 to 3/98; V.P. Regional Manager 9/96 to 7/97; prior
                                           thereto various Vice President positions with Santa Barbara
                                           Bank & Trust Co. and Bank of A Levy
 
E. Thomas Martin.................  55    President, Martin Resorts, Inc. (hotel) 1998 to present; Manager,   1996
                                           Martin & Hobbs LLC (real estate and vineyards) 1996 to present;
                                           President, Martin & MacFarlane, Inc. (outdoor advertising and
                                           winery) 1976-1998; President, MW Sign Corp. (management
                                           company) 1991-1998
 
Harry L. Maynard.................  71    Retired, former President of ACB                                    1976
 
Edward F. Paul...................  61    President, Walker, Inc. (real estate management and sales);         1998
                                           President, CIB 1995-96
 
Joseph L. Priske.................  49    Vice Chairman of the Board; CEO, Priske-Jones Company (real         1998
                                           estate development)
 
Jacqueline S. Pruner.............  60    Consultant, American Medical Response 6/94-5/97; Co-Owner, Pruner   1998
                                           Investments
</TABLE>
 
                                       17
<PAGE>
    The following table sets forth information on the current executive officers
of Americorp or ACB.
 
<TABLE>
<CAPTION>
                                                                                                            YEAR
                                                                                                            FIRST
                                                                                                            ELECTED
                                                                                                            OR
NAME                               AGE   BUSINESS EXPERIENCE FOR PAST FIVE YEARS                            APPOINTED
---------------------------------  ---   -----------------------------------------------------------------  -------
<S>                                <C>   <C>                                                                <C>
Gerald J. Lukiewski .............  45    Banker, President of ACB 3/98 to present; S.V.P. Chief Credit       1998
  President                                Officer 7/97 to 3/98; V.P. Regional Manager 9/96 to 7/97; prior
                                           thereto various Vice President positions with Santa Barbara
                                           Bank & Trust Co. and Bank of A Levy
 
Thomas E. Anthony ...............  50    Senior Vice President and Chief Lending Officer of CIB              1998
  Sr. VP and Chief Lending
  Officer
 
Allen R. Partridge ..............  58    Senior Vice President and Chief Financial Officer of CIB from       1998
  Sr. VP and Chief Financial               3/97; in house con- sultant acting as chief accountant and
  Officer                                  information systems manager for the Israel Discount Bank from
                                           5/96 to 3/97; Chief Operating Officer and Chief Financial
                                           Officer for Bank of Los Angeles from 11/93 to 6/95
 
Mary Martha Stewart .............  38    Senior Vice President and Chief Operating Officer of ACB from       1998
  Sr. VP and Chief Operating               3/98; Senior Vice President Operations for Colonial Western
  Officer                                  Agency, Inc. from 10/97 to 1/98; Group Vice President and Area
                                           Manager for City National Bank from 1/97 to 9/97; Senior Vice
                                           President Branch Administration for Ventura County National
                                           Bank (acquired by City National) from 5/90 to 1/97
</TABLE>
 
                                       18
<PAGE>
ITEM 11. EXECUTIVE COMPENSATION
 
EXECUTIVE COMPENSATION
 
    Set forth below is the compensation accrued during 1998 to the five highest
paid executive officer of Americorp/ACB who received total annual salary and
bonus of more than $100,000 during 1998.
 
                           SUMMARY COMPENSATION TABLE
 
<TABLE>
<CAPTION>
                                                                              ANNUAL COMPENSATION
                                                                      -----------------------------------
                                                                                                 (E)
                                                                                                OTHER           (D)
                           (A)                                           (C)        (D)        ANNUAL        ALL OTHER
                        NAME AND                              (B)      SALARY      BONUS       COMPEN-     COMPENSATION
                   PRINCIPAL POSITION                        YEAR      ($)(1)       ($)     SATION($)(2)        ($)
---------------------------------------------------------  ---------  ---------  ---------  -------------  -------------
<S>                                                        <C>        <C>        <C>        <C>            <C>
Gerald J. Lukiewski .....................................       1998    114,166     50,000           --             --
  President(3)                                                   N/A
 
Mary Martha Stewart .....................................       1998     62,500     40,468           --             --
  Senior V.P.                                                    N/A
 
Thomas E. Anthony(4) ....................................       1998     97,060     15,000           --             --
  Senior VP                                                      N/A
 
Allen R. Partridge(4) ...................................       1998     88,400     15,000           --             --
  Senior VP                                                      N/A
 
James E. Beeninga .......................................       1998     11,940         --        7,000(6)     119,027(7)
  President(5)                                                  1997    139,100     26,065           --             --
</TABLE>
 
------------------------
 
(1) Amounts shown include cash and non-cash compensation earned and received,
    including monthly auto allowances.
 
(2) No executive officer received perquisites or other personal benefits in
    excess of the lesser of $50,000 or 10% of each such officer's total annual
    salary and bonus.
 
(3) Became President on March 2, 1998 and Senior Vice President and Chief Credit
    Officer prior thereto.
 
(4) Reflects services and compensation received at CIB prior to the merger on
    December 31, 1998.
 
(5) Resigned as President on March 2, 1998.
 
(6) Reflects the difference between the exercise price and the fair market value
    on the exercise of a stock option for 1,000 shares of Americorp stock.
 
(7) Reflects amounts paid to Mr. Beeninga in connection with his resignation.
 
OPTION GRANTS IN 1998
 
    In connection with the merger with CIB, Americorp adopted a new stock option
plan. Previous stock option plans of Americorp were terminated at such time but
options granted pursuant to such plans remained outstanding and exercisable in
accordance with their terms. Options granted during 1998 under
 
                                       19
<PAGE>
the various Americorp stock option plans to any of the officers set forth in the
Summary Compensation Table are as follows:
 
<TABLE>
<CAPTION>
                                                          (B)                (C)
                                                       NUMBER OF         PERCENT OF          (D)
                                                      SECURITIES       OPTIONS GRANTED   EXERCISE OR
                       (A)                            UNDERLYING        TO EMPLOYEES     BASE PRICE         (E)
                      NAME                          OPTIONS GRANTED        IN 1998        PER SHARE   EXPIRATION DATE
-------------------------------------------------  -----------------  -----------------  -----------  ---------------
<S>                                                <C>                <C>                <C>          <C>
Lukiewski........................................          1,000               3.01       $   31.50        3/25/03
Stewart..........................................          4,000              12.05       $   31.50        3/25/03
Anthony..........................................          3,641              10.97       $   27.46        6/18/08
Partridge........................................          3,641              10.97       $   27.46        6/18/08
Beeninga.........................................             --                 --              --             --
</TABLE>
 
    The following table sets forth certain information concerning unexercised
options under the Americorp stock option plans to the persons named in the
Summary Compensation Table.
 
<TABLE>
<CAPTION>
                                                                                             (D)
                                                                                          NUMBER OF          (E)
                                                                                         SECURITIES       VALUE OF
                                                                                         UNDERLYING      UNEXERCISED
                                                                                         UNEXERCISED    IN-THE-MONEY
                                                                                         OPTIONS AT        OPTIONS
                                                                 (B)                     12/31/98(#)   AT 12/31/98($)
                                                               SHARES          (C)      -------------  ---------------
                           (A)                               ACQUIRED ON    REALIZED    EXERCISABLE/    EXERCISABLE/
                           NAME                              EXERCISE(#)     ($)(1)     UNEXERCISABLE   UNEXERCISABLE
----------------------------------------------------------  -------------  -----------  -------------  ---------------
<S>                                                         <C>            <C>          <C>            <C>
Lukiewski.................................................           --            --    2,600/2,400     21,500/18,000
Stewart...................................................           --            --      800/3,200      4,400/17,600
Anthony...................................................           --            --      729/2,912      7,684/30,692
Partridge.................................................           --            --      729/2,912      7,684/30,692
Beeninga..................................................        1,000         7,000        --              --
</TABLE>
 
------------------------
 
(1) The aggregate value has been determined based upon the average of the bid
    and asked prices for Americorp's stock at exercise or year-end, minus the
    exercise price.
 
DIRECTOR COMPENSATION
 
    In 1998, each of the then directors received $1,000 per month in director's
fees except as indicated in the following sentences. The Secretary to the Board
(Mr. Cryne - retired) received $2,000 per month in fees and the Vice-Chairman of
the Board, (Mr. Lagomarsino) also received $2,000 per month in fees. Mr. Jue
(the Chairman of the Board) received $3,500 per month in fees.
 
    During 1998, ACB's Directors' Retirement Plan was terminated and the
benefits payable thereunder frozen. Benefits will only be payable upon
retirement and then either on a lump sum basis or pursuant to a 10 year pay-out.
Directors Cryne (retired), Jue, Lagomarsino and Wood (retired) were the only
participants in the plan. It is currently anticipated that the amount of such
additional accrual will be approximately $175,600.
 
EMPLOYMENT AGREEMENTS
 
    In connection with his appointment as President and Chief Executive Officer
of Americorp and ACB, ACB entered into an employment agreement with Gerald J.
Lukiewski as of March 2, 1998. The agreement, as amended and extended, currently
provides for a three year term with an annual salary of $135,000. The agreement
also provides for participation in ACB's bonus plan and certain other benefits,
including vacation, automobile allowance, insurance, retirement benefits and
expense reimbursements. In the event of termination without cause, the agreement
provides for the lesser of (i) three months of
 
                                       20
<PAGE>
additional salary and benefits or (ii) the remaining salary and benefits due
under the term of the agreement.
 
    On July 7, 1998, CIB entered into an employment agreement with Mr. Thomas
Anthony as CIB's Senior Vice President and Senior Lending Officer. The term of
the agreement commenced on June 18, 1998 and shall terminate on December 31,
1999. Mr. Anthony shall receive a salary of $95,258.89 per year, four weeks of
vacation, use of a Bank owned automobile, a stock option of 5,000 shares vesting
20% per year at an exercise price of $20.00 per share, certain health and
medical benefits, and reimbursement of certain business expenses. Mr. Anthony
may be terminated with cause for any of the various reasons enumerated in the
agreement, and upon such termination, Mr. Anthony would receive only accrued
salary and payment for any unused vacation. The agreement also provides for the
payment of six months salary if Mr. Anthony is terminated without cause. If Mr.
Anthony is terminated, Mr. Anthony may not, for a one year period following
termination, solicit any customers or employees to move their banking or
employment relationships.
 
    Also on July 7, 1998, CIB entered into an employment agreement with Mr.
Allen Partridge as CIB's Senior Vice President and Chief Financial Officer. The
term of the agreement commenced on June 18, 1998 and shall terminate on December
31, 1999. Mr. Partridge shall receive a salary of $88,400 per year, four weeks
of vacation, a stock option of 5,000 shares vesting 20% per year at an exercise
price of $20.00 per share, certain health and medical benefits, and
reimbursement of certain business expenses. Mr. Partridge may be terminated with
cause for any of the various reasons enumerated in the agreement, and upon such
termination, Mr. Partridge would receive only accrued salary and payment for any
unused vacation. The agreement also provides for the payment of six months
salary if Mr. Partridge is terminated without cause. If Mr. Partridge is
terminated, Mr. Partridge may not, for a one year period following termination,
solicit any customers or employees to move their banking or employment
relationships.
 
    The employment agreements of Messrs. Anthony and Partridge were assumed by
Americorp and ACB in connection with the merger of CIB with and into ACB.
 
                                       21
<PAGE>
ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
 
    Except as set forth in the following table, management of Americorp does not
know of any person who owns beneficially more than 5% of Americorp Stock. The
following table sets forth certain information as of February 1, 1999,
concerning the beneficial ownership of Americorp Stock by each of the current
directors of Americorp and ACB and by all current directors and executive
officers of Americorp and ACB as a group.
 
<TABLE>
<CAPTION>
                                                                    AMOUNT OF
                                                                   BENEFICIAL        PERCENT OF
                  NAME OF BENEFICIAL OWNER                        OWNERSHIP(1)        CLASS(2)
-------------------------------------------------------------  -------------------  -------------
<S>                                                            <C>                  <C>
Michael T. Hribar............................................           6,623(3)              *
Allen W. Jue.................................................          17,681(4)            1.7%
Robert J. Lagomarsino........................................          41,312               4.0%
Gerald J. Lukiewski..........................................           3,300(5)              *
E. Thomas Martin.............................................          55,575(6)            5.4%
Harry L. Maynard.............................................          15,202               1.5%
Edward F. Paul...............................................          41,044(7)            4.0%
Joseph L. Priske.............................................           9,443(8)              *
Jacqueline S. Pruner.........................................          21,106(9)            2.0%
Directors and Executive Officers
  as a Group (12 persons)....................................         217,985(10)          20.7%
</TABLE>
 
------------------------
 
*   Less than 1%.
 
(1) Beneficial owner of a security includes any person who, directly or
    indirectly, through any contract, arrangement, understanding, relationship,
    or otherwise has or shares; (a) voting power, which includes the power to
    vote, or to direct the voting of such security; and/or; (b) investment power
    which includes the power to dispose, or to direct the disposition of such
    security. Beneficial owner also includes any person who has the right to
    acquire beneficial ownership of such security as defined above within 60
    days of the date specified.
 
(2) Shares subject to options held by directors and executive officers that were
    exercisable within 60 days after February 1, 1999 are treated as issued and
    outstanding for the purpose of computing the percentage of class owned by
    such person (or group) but not for the purpose of computing the percentage
    of class owned by any other individual person.
 
(3) Includes 1,457 shares exercisable pursuant to the Americorp stock option
    plans.
 
(4) Includes 5,000 shares exercisable pursuant to the Americorp stock option
    plans.
 
(5) Includes 2,800 shares exercisable pursuant to the Americorp stock option
    plans.
 
(6) Includes 2,000 shares exercisable pursuant to the Americorp stock option
    plans.
 
(7) Includes 1,457 shares exercisable pursuant to the Americorp stock option
    plans.
 
(8) Includes 1,457 shares exercisable pursuant to the Americorp stock option
    plans.
 
(9) Includes 729 shares exercisable pursuant to the Americorp stock option
    plans.
 
(10) Includes 17,958 shares exercisable pursuant to the Americorp stock option
    plans.
 
                                       22
<PAGE>
ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS
 
    Some of the current directors and officers of Americorp and ACB and the
companies with which they are associated have been customers of, and have had
banking transactions with ACB, in the ordinary course of ACB's business, and ACB
expects to continue to have such banking transactions in the future. All loans
and commitments to lend included in such transactions have been made on
substantially the same terms, including interest rates and collateral, as those
prevailing at the time for comparable transactions with persons of similar
creditworthiness, and in the opinion of management of ACB, have not involved
more than the normal risk of repayment or presented any other unfavorable
features.
 
ITEM 14. EXHIBITS AND REPORTS ON FORM 8-K
 
<TABLE>
<C>    <S>
EXHIBITS:
 
  2.1  Agreement to Merge and Plan of Reorganization, dated July 7, 1998, and
         amended on September 17, 1998*
  3.1  Articles of Incorporation of Americorp*
  3.2  Bylaws of Americorp, as amended*
 10.1  Employment Agreement of Gerald J. Lukiewski*
 10.2  1994 Stock Option Plan*
 10.3  1998 Stock Option Plan*
 10.4  ACB 401K Profit Sharing Plan*
 10.5  Restated and Amended Senior Executives Retirement Plan*
 10.6  Restated and Amended Chief Executive Officer Retirement Plan*
 10.7  Restated and Amended Directors Retirement Plan*
 10.8  Data processing Agreement with Electronic Data Systems Corp.*
 10.9  Employment Agreement of Allen Partridge
 10.10 Employment Agreement of Thomas Anthony
 16    Letter concerning change in certifying accountant**
 21    Subsidiary of Americorp - American Commercial Bank is the only subsidiary
         of Americorp
 23    Consent of Vavrinek, Trine, Day & Co., LLP
 27    Financial Data Schedule
</TABLE>
 
------------------------
 
* filed with the SEC in Registration Statement 333-63841 on Form S-4 and by this
    reference incorporated herein
 
** contained in Americorp's Report on Form 8-K filed with the SEC on December 4,
    1998 and by this reference incorporated herein.
 
REPORTS ON FORM 8-K:
 
    On December 4, 1998, the Company filed a report on Form 8-K in connection
with item 4 - Change in Accountants.
 
    On January 13, 1999, the Company filed a report on Form 8-K in connection
with items 2 and 7 regarding the closing of the transaction with Channel Islands
Bank.
 
                                       23
<PAGE>
                                   SIGNATURES
 
    In accordance with Section 13 or 15(d) of the Securities Exchange Act of
1934, Americorp caused this Report to be signed on its behalf by the
undersigned, thereunto duly authorized on March 18, 1999.
 
<TABLE>
<S>                             <C>  <C>
                                AMERICORP
 
                                By:           /s/ GERALD J. LUKIEWSKI
                                     -----------------------------------------
                                                Gerald J. Lukiewski
                                       PRESIDENT AND CHIEF EXECUTIVE OFFICER
 
                                By:             /s/ ALLEN PARTRIDGE
                                     -----------------------------------------
                                                  Allen Partridge
                                              CHIEF FINANCIAL OFFICER
</TABLE>
 
    In accordance with the Securities Exchange Act of 1934, this Report has been
signed below by the following persons on behalf of Americorp and in the
capacities and on the dates indicated.
 
                                                                     Dated:
 
         /s/ ALLEN W. JUE
-----------------------------------  Chairman of the Board of    March 18, 1999
           Allen W. Jue               Directors
 
       /s/ MICHAEL T. HRIBAR
-----------------------------------  Director                    March 18, 1999
         Michael T. Hribar
 
     /s/ ROBERT J. LAGOMARSINO
-----------------------------------  Director                    March 18, 1999
       Robert J. Lagomarsino
 
      /s/ GERALD J. LUKIEWSKI
-----------------------------------  Director                    March 18, 1999
        Gerald J. Lukiewski
 
       /s/ E. THOMAS MARTIN
-----------------------------------  Director                    March 18, 1999
         E. Thomas Martin
 
       /s/ HARRY L. MAYNARD
-----------------------------------  Director                    March 18, 1999
         Harry L. Maynard
 
        /s/ EDWARD P. PAUL
-----------------------------------  Director                    March 18, 1999
          Edward P. Paul
 
-----------------------------------  Director                    March   , 1999
         Joseph L. Priske
 
     /s/ JACQUELINE S. PRUNER
-----------------------------------  Director                    March 18, 1999
       Jacqueline S. Pruner
 
                                       24
<PAGE>
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
 EXHIBIT
SEQUENTIAL                                                                                 PAGE
  NUMBER                                    DESCRIPTION                                   NUMBER
----------  ---------------------------------------------------------------------------  ---------
<S>         <C>                                                                          <C>
  10.9      Employment Agreement of Allen Partridge
 
  10.10     Employment Agreement of Thomas Anthony
 
  23        Consent of Vavrinek, Trine, Day & Co., LLP
 
  27        Financial Data Schedule
</TABLE>
 
                                       25