<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM 10-K

Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of
1934

For the Fiscal Year Ended December 31, 1998      Commission File Number 0-11928

                             AMERICAN BANCORP, INC.
             (Exact name of registrant as specified in its charter)

           Louisiana                        72-0951347
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
incorporation or organization)

       328 East Landry Street
         Opelousas, Louisiana               70570
(Address of principal executive offices)    (Zip Code)

Registrant's Telephone Number, including area code: (318) 948-3056

Securities registered pursuant to Section 12(b) of the Act: None

Securities registered pursuant to Section 12(g) of the Act:
                          Common Stock, $5.00 Par Value
                                (Title of Class)

Indicate by check mark whether the registrant: (l) 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 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. [ ]

The aggregate market value of the voting stock held by non-affiliates* of the
registrant:  $3,979,560.

The number of shares outstanding of each of the issuer's classes of common
stock, as of December 31, 1998: Common Stock, $5.00 Par Value, 118,449 shares
outstanding.

                       Documents Incorporated by Reference

Portions of the annual shareholders' report for the year ended December 31, 1998
are incorporated by reference into Parts I and II.

Portions of the proxy statement for the annual shareholders meeting to be held
April 14, 1999 are incorporated by reference into Part III.

        *For purposes of the computation, shares owned by executive officers,
directors, 5% shareholders and shares by non-affiliates whose voting rights have
been assigned to directors have been excluded.

                                     - 1 -

<PAGE>   2



                                     PART I

Item 1.  Business

        American Bancorp, Inc. (the Company) was incorporated under the laws of
the State of Louisiana in 1982. On October 1, 1983, American Bank and Trust
Company (the Bank) was reorganized as a subsidiary of the Company. Prior to
October 1, 1983, the Company had no material activity. The Company is currently
engaged, through its subsidiary, in banking and related business. The Bank is
the Company's principal asset and primary source of revenue.

The Bank

        The Bank, incorporated under the State Banking Laws on August 1, 1958 is
in the business of gathering funds by accepting checking, savings, and other
time-deposit accounts and reemploying these by making loans and investing in
securities and other interest-bearing assets. The Bank is a full service
commercial bank. Some of the major services which it provides include checking,
NOW accounts, Money Market checking, savings, and other time deposits of various
types, loans for business, agriculture, real estate, personal use, home
improvement, automobile, and a variety of other types of loans and services
including letters of credit, safe deposit boxes, bank money orders, wire
transfer facilities, and electronic banking facilities.

        The State of Louisiana, through its various departments and agencies,
deposits public funds with the Bank. However, as of December 31, 1998, the State
of Louisiana did not have any funds on deposit with the Bank.

        The Bank's general market area is in St. Landry Parish, which has a
population of approximately 81,939. Its primary market is Opelousas, which has a
population of approximately 19,540, and has experienced little population growth
over the past several years.

        The commercial banking business in St. Landry Parish is highly
competitive. The Depository Institutions Deregulation and Monetary Control Act
of 1980 and the Garn-St. Germain Depository Institutions Act of 1982 have
eliminated most, if not all, substantive distinctions between the services of
commercial banks and thrift institutions. The Bank competes with three banks and
two savings and loan institutions located in St. Landry Parish. The following is
a list of banks and savings associations in this market with the total deposits
and assets as of December 31, 1998.

<TABLE>
<CAPTION>
                                                (In thousands of dollars)
                                              Assets              Deposits
                                            ---------            ---------

<S>                                         <C>                  <C>      
American Bank and Trust Company             $  73,666            $  63,819
St. Landry Bank and Trust Company           $ 220,090            $ 187,346
St. Landry Homestead                        $ 132,653            $ 109,725
Washington State Bank                       $  81,329            $  63,716
First Federal Savings & Loan                $  65,823            $  48,474
</TABLE>





                                      - 2 -

<PAGE>   3


Item 1.  Business (continued)

        In addition to the institutions listed above, further competition is
provided by banks and other financial institutions located in Lafayette,
Louisiana, which is 20 miles south of Opelousas and Baton Rouge, Louisiana, the
state capital, which is 60 miles east of St. Landry Parish.

        Louisiana Banking Law provides that generally Louisiana banks having
capital of one hundred thousand dollars or more may open one or more branch
offices within the State or may acquire one or more banks or any or all branches
thereof, or both. On July 2, 1986, Louisiana passed an interstate banking law
affirmatively permitting Louisiana bank holding companies to immediately acquire
out-of-state bank holding companies and banks. On July 1, 1987, bank holding
companies located in a fifteen state region were permitted to acquire banks or
bank holding companies in Louisiana, and beginning January 1, 1991, out-of-state
bank holding companies may acquire banks or bank holding companies provided that
the law of the state in which the out-of-state bank holding company has its
principal place of business permits Louisiana bank holding companies to acquire
banks and bank holding companies in that state.

        The effect of the new liberalized branching laws and the Louisiana
Interstate Banking Law on the Company cannot be predicted at this time, but
increased competition is expected.

Employees

        During 1998, the average number of full-time equivalent employees at the
Bank was 44. This includes the officers of the Company that are listed under
Item 1 below.

        There are no unions or bargaining units that represent the employees of
the Bank. The relation between management and employees is considered to be
good.

Executive Officers

        The executive officers of the Company are as follows:

<TABLE>
<CAPTION>
                          Years of
   Officer Name            Service        Age            Position Currently Held   
----------------------    --------        ---       --------------------------------

<S>                          <C>           <C>      <C>                            
Salvador L. Diesi, Sr.       25            68       Chairman of the Board of the
                                                      Company and the Bank;
                                                      President of the Company
                                                      and the Bank

Ronald J. Lashute            26            49       Executive Vice-President and
                                                      Chief Executive Officer of the
                                                      Bank and Secretary/Treasurer
                                                      of the Company
</TABLE>






                                      - 3 -

<PAGE>   4


Item 1.  Business (continued)

        None of the directors and executive officers of the Company or the Bank
holds a directorship in any company with a class of securities registered under
Section 12 of the Securities Exchange Act of 1934, as amended, or subject to the
requirements of Section 15(d) of that Act or in any company registered as an
investment company under the Investment Company Act of 1940. Salvador L. Diesi,
Sr. and Ronald J. Lashute are the nephews of J.C. Diesi. No other family
relationships exist among the above named directors or executive officers of the
Company.

Supervision and Regulation

        The Bank is subject to regulation and regular examinations by the
Louisiana Commissioner of Financial Institutions and by the Federal Deposit
Insurance Corporation. Applicable regulations relate to reserves, investments,
loans, issuance of securities, establishment of branches, and other aspects of
its operations.

        The Federal Deposit Insurance Corporation Improvement Act of 1991
("FDICIA") further expanded the regulatory and enforcement powers of bank
regulatory agencies. Among the significant provisions of FDICIA is the
requirement that bank regulatory agencies prescribe standards relating to
internal controls, information systems, loan documentation, credit underwriting,
interest rate exposure, asset growth, compensation, fees and benefits. FDICIA
mandates annual examinations of banks by their primary regulators.

        The Company is a bank holding company within the meaning of the Bank
Holding Company Act of 1956, as amended (the Act), and is thereby subject to the
provisions of the Act and to regulation by the Board of Governors of the Federal
Reserve System (the Board).

        The Act requires the Company to file with the Board an annual report
containing such information as the Board may require. The Board is authorized by
the Act to examine the Company and all of its activities. The activities that
may be engaged in by the Company and its subsidiary are limited by the Act to
those so closely related to banking or managing or controlling banks as to be a
proper incident thereto. In determining whether a particular activity is a
proper incident to banking or managing or controlling banks, the Board must
consider whether its performance by an affiliate of a holding company can
reasonably be expected to produce benefits to the public, such as greater
convenience, increased competition or gains in efficiency that outweigh possible
adverse effects, such as undue concentration of resources, decreased or unfair
competition, conflicts of interest, or unsound banking practices.

        The Board has adopted regulations implementing the provisions of the Act
with respect to the non-banking activities of bank holding companies. Such
regulations reflect a determination by the Board that certain specified
activities are permissible for a bank holding company. An activity not listed in
the regulation may be engaged in if, upon application, the Board determines that
the activity meets the criteria described in the preceding paragraph. In each
case, a bank holding company must secure the approval of the Board prior to
engaging in any of these activities.

        Whether or not a particular non-banking activity is permitted under the
Act, the Board is authorized to require a holding company to terminate any
activity, or divest



                                      - 4 -

<PAGE>   5


Item 1.  Business (continued)

itself of any non-banking subsidiary, if in its judgment the activity or
subsidiaries would be unsound.

        Under the Act and the Board's regulations, a bank holding company and
its subsidiaries are prohibited from engaging in certain tie-in arrangements in
connection with any extension of credit or provision of any property or
services.

        In some cases, the Company must receive the prior approval of the Board
in order to repurchase or redeem its outstanding equity securities.

        With certain exceptions, the Subsidiary Bank is restricted by Sections
22 and 23A of the Federal Reserve Act from extending credit or making loans to
or investments in the Company and certain other affiliates as defined in the
Federal Reserve Act. Such transactions by the Subsidiary Bank with the Company
or any such affiliate are limited in an amount to 10% of the Subsidiary Bank's
capital and surplus. Furthermore, loans and extensions of credit are subject to
various collateral requirements.

        The Louisiana bank holding company law, as amended (the "Louisiana
Act"), permits bank holding companies to own more than one bank. In addition, a
bank holding company and its subsidiaries may not engage in any insurance
activity in which a bank may not engage. The Louisiana Commissioner of Financial
Institutions is authorized to administer the Louisiana Act and to issue orders
and regulations.

        The Board of Directors of the Company have no present plans or
intentions to cause the Company to engage in any substantial business activity
which would be permitted to it under the Act or the Louisiana Act but which is
not permitted to the Bank; however, a significant reason for formation of the
one-bank holding company is to take advantage of the additional flexibility
afforded by that structure if the Board of Directors of the Company concludes
that such action would be in the best interest of stockholders.

Statistical Information

        The following tables contain additional information concerning the
business and operations of the Registrant and its subsidiary and should be read
in conjunction with the Consolidated Financial Statements of the Registrant and
Management's Discussion and Analysis of Financial Condition and Results of
Operations. The 1998 Annual Report to Shareholders is incorporated herein by
reference under Item 8.

Investment Portfolio

        The following table sets forth the carrying amount of Investment
Securities at the dates indicated (in thousands of dollars):

<TABLE>
<CAPTION>
                                                            December 31,          
                                             ------------------------------------------
                                               1998             1997             1996  
                                             --------         --------         --------
<S>                                          <C>              <C>              <C>     
Securities held to maturity:
   U.S. Treasury                             $  2,696         $  3,692         $  4,005
   U.S. Government Agencies                     3,005           10,512           11,513
                                             --------         --------         --------
                                             $  5,701         $ 14,204         $ 15,518
                                             ========         ========         ========
</TABLE>





                                      - 5 -

<PAGE>   6


Item 1.  Business (continued)

<TABLE>
<CAPTION>
                                                        December 31,          
                                         ------------------------------------------
                                           1998             1997             1996  
                                         --------         --------         --------
<S>                                      <C>              <C>              <C>     
Securities available for sale:
   Mortgage-backed securities            $  4,455         $  1,210         $  1,787
   U.S. Treasury securities                 3,553            2,009            1,002
   U.S. Government Agencies                 9,002            5,532            3,012
   State and Political subdivisions         6,907            3,442            2,870
   Equity securities                           97               -                - 
                                         --------         --------         --------

                                         $ 24,014         $ 12,193         $  8,671
                                         ========         ========         ========
</TABLE>

        The following tables set forth the maturities of investment securities
at December 31, 1998, 1997, and 1996 and the weighted average yields of such
securities (in thousands of dollars):

<TABLE>
<CAPTION>
                                                                       December 31, 1998                      
                                  ---------------------------------------------------------------------------------------
                                                             After One               After Five
                                                             But Within              But Within               After
                                    Within One Year          Five Years              Ten Years              Ten Years   
                                  ------------------     ------------------     -------------------    ------------------
                                   Amount      Yield      Amount      Yield      Amount       Yield     Amount      Yield
                                  -------      -----     -------      -----     -------       -----    -------      -----
<S>                               <C>          <C>       <C>          <C>       <C>           <C>      <C>          <C>  
Securities held
   to maturities:
      U.S. Treasury               $ 2,496      6.25%     $    200     4.54%     $     -         - %    $     -        - %
      U.S. Government
      Agencies                        506      6.22         1,999     6.91           500      7.03           -        -
                                  -------                --------               --------               --------

            Total held
              to
              maturity              3,002      6.24         2,199     6.69           500      7.03          -0-       -
                                  -------                --------               --------               --------

Securities
   available for
   sale:
      U.S. Treasury                    -         -          3,553     5.75            -         -            -        -
      U.S. Government
         Agencies                      -         -          7,966     6.25         1,036      6.06           -        -
      Mortgage-backed
         securities                    -         -            669     6.85         2,301      5.77        1,485     6.82
      State and
         Political
         Subdivisions                 222      7.48         3,011     7.16         3,113      7.12          561     7.11
      Equity
         securities                    97        -             -        -             -         -            -        -
                                  -------                --------               --------               --------

            Total
              available
              for sale                319      7.48        15,199     6.34         6,450      6.47        2,046     6.90
                                  -------                --------               --------               --------

            Total
              securities          $ 3,321      6.33%     $ 17,398     6.38%     $  6,950      6.51%    $  2,046     6.90%
                                  =======     =====      ========    =====      ========     =====     ========    =====
</TABLE>




                                      - 6 -

<PAGE>   7


Item 1.  Business (continued)

<TABLE>
<CAPTION>
                                                                       December 31, 1997                      
                                  ---------------------------------------------------------------------------------------
                                                             After One               After Five
                                                             But Within              But Within               After
                                    Within One Year          Five Years              Ten Years              Ten Years   
                                  ------------------     ------------------     -------------------    ------------------
                                   Amount      Yield      Amount      Yield      Amount       Yield     Amount      Yield
                                  -------      -----     -------      -----     -------       -----    -------      -----
<S>                               <C>          <C>       <C>          <C>       <C>           <C>      <C>          <C>  
Securities held
   to maturities:
      U.S. Treasury               $ 1,200      5.95%     $  2,492     6.25%     $     -         - %    $     -        - %
      U.S. Government
      Agencies                      2,498      5.92         7,016     6.49           998      7.16           -        -
                                  -------                --------               --------               --------

            Total held
              to
              maturity              3,698      5.93         9,508     6.43           998      7.16          -0-       -
                                  -------                --------               --------               --------

Securities
   available for
   sale:
      U.S. Treasury                 1,001      6.27         1,008     6.28            -         -            -        -
      U.S. Government
         Agencies                      -         -          5,532     6.53            -         -            -        -
      Mortgage-backed
         securities                     4      9.35           407     8.66            68      9.16          731     8.66
      State and
         Political
         Subdivisions                  10      6.43         2,006     7.29         1,221      7.01          205     8.68
                                  -------                --------               --------               --------

            Total
              available
              for sale              1,015      6.28         8,953     6.76         1,289      7.11          936     8.67
                                  -------                --------               --------               --------

            Total
              securities          $ 4,713      6.01%     $ 18,461     6.59%     $  2,287      7.13%    $    936     8.67%
                                  =======     =====      ========    =====      ========     =====     ========    =====
</TABLE>





                                      - 7 -

<PAGE>   8


Item 1.  Business (continued)

<TABLE>
<CAPTION>
                                                                       December 31, 1996                      
                                  ---------------------------------------------------------------------------------------
                                                             After One               After Five
                                                             But Within              But Within               After
                                    Within One Year          Five Years              Ten Years              Ten Years   
                                  ------------------     ------------------     -------------------    ------------------
                                   Amount      Yield      Amount      Yield      Amount       Yield     Amount      Yield
                                  -------      -----     -------      -----     -------       -----    -------      -----
<S>                               <C>          <C>       <C>          <C>       <C>           <C>      <C>          <C>  
Securities held
   to maturities:
      U.S. Treasury               $ 1,801      6.15%     $  2,204     5.88%     $     -         - %    $     -        - %
      U.S. Government
      Agencies                      4,496      6.64         7,017     6.56            -         -            -        -
                                  -------                --------               --------               --------

            Total held
              to
              maturity              6,297      6.50         9,221     6.40           -0-        -           -0-       -
                                  -------                --------               --------               --------

Securities
   available for
   sale:
      U.S. Treasury                    -         -          1,002     6.27            -         -            -        -
      U.S. Government
         Agencies                   1,507      7.03         1,505     6.44            -         -            -        -
      Mortgage-backed
         securities                   124      8.24           906     8.20           757      9.14           -        -
      State and
         Political
         Subdivisions                  -         -          1,481     7.81         1,389      7.04           -        -
                                  -------                --------               --------               --------

            Total
              available
              for sale              1,631      7.12         4,894     7.15         2,146      7.78          -0-       -
                                  -------                --------               --------               --------

            Total
              securities          $ 7,928      6.63%     $ 14,115     6.67%     $  2,146      7.78%    $    -0-       - %
                                  =======     =====      ========    =====      ========     =====     ========    =====
</TABLE>


* Weighted average yields have been computed on a fully tax-equivalent basis
assuming a rate of 34% for 1998, 1997 and 1996.





                                      - 8 -

<PAGE>   9


Item 1.  Business (continued)

Loan Portfolio

        The amounts of loans outstanding at the indicated dates are shown in the
following table according to type of loan (in thousands of dollars):

<TABLE>
<CAPTION>
                                                                                              December 31,          
                                                                               ------------------------------------------
                                                                                 1998             1997             1996  
                                                                               --------         --------         --------

<S>                                                                            <C>              <C>              <C>     
Commercial, financial and agricultural                                         $  7,666         $  7,549         $  7,437
Real Estate - Construction                                                           51              359              285
Real Estate - Mortgage                                                           15,361           15,543           16,278
Installment                                                                       4,981            4,984            4,925
                                                                               --------         --------         --------

          Total                                                                  28,059           28,435           28,925

Less:
  Allowance for possible loan losses                                               (596)            (600)            (614)
  Unearned income                                                                    -                -                - 
                                                                               --------         --------         --------

                                                                               $ 27,463         $ 27,835         $ 28,311
                                                                               ========         ========         ========
</TABLE>


        The following table presents information concerning the aggregate amount
of nonperforming loans. Nonperforming loans comprise: (a) loans accounted for on
a nonaccrual basis; (b) loans contractually past due ninety days or more as to
interest or principal payments [but not included in the nonaccrual loans in (a)
above]; (c) other loans whose terms have been restructured to provide a
reduction or deferral of interest or principal because of a deterioration in the
financial position of the borrower [exclusive of loans in (a) or (b) above]; and
(d) loans now current where there are serious doubts as to the ability of the
borrower to comply with present loan requirement terms (in thousands of
dollars):

<TABLE>
<CAPTION>
                                                                                               December 31,          
                                                                               ------------------------------------------
                                                                                 1998             1997             1996  
                                                                               --------         --------         --------

<S>                                                                            <C>              <C>              <C>     
Loans accounted for on a nonaccrual basis                                      $    145         $    308         $    496

Restructured loans which are not on
  non-accrual                                                                        61               70               94
                                                                               --------         --------         --------

                                                                                    206              378              590
Other real estate and repossessed assets
  received in complete or partial
  satisfaction of loan obligations                                                   -                 7               14
                                                                               --------         --------         --------

    Total nonperforming assets                                                 $    206         $    385         $    604
                                                                               ========         ========         ========

Loans contractually past due ninety days
  or more as to principal or interest,
  but which were not on non-accrual                                            $     15         $      9         $     27
                                                                               ========         ========         ========
</TABLE>



                                      - 9 -

<PAGE>   10


Item 1.  Business (continued)

        As of January 1, 1995, the Company adopted SFAS No. 114, "Accounting by
Creditors for Impairment of a Loan," which, as it relates to in-substance
foreclosures, requires that a creditor continue to classify these assets as
loans in the balance sheet unless the creditor receives physical possession of
the collateral. The Company had no in-substance foreclosures at the date of
adoption of SFAS No. 114. At December 31, 1998, the recorded investment in loans
that were considered to be impaired under SFAS No. 114 was $144,797, with the
related allowance for loan losses of $100,000. These loans are included in
nonaccrual loans.

        The effect of nonperforming loans on interest income has not been
substantial in the past three years. Had interest been accrued on the
nonperforming loans, interest income would have been recorded in the amount of
$32,424, $53,417 and $59,177, for the years 1998, 1997, and 1996, respectively.
Interest income in the amount of $4,796, $5,621 and $6,633 on nonperforming
loans during 1998, 1997 and 1996, respectively, was recorded.

        At December 31, 1998, 1997 and 1996 there were no significant
commitments to lend additional funds to debtors whose loans were considered to
be nonperforming.

        The Bank places loans on nonaccrual when the borrower is no longer able
to make periodic interest payments due to a deterioration of the borrowers
financial condition.

        At December 31, 1998, the Bank has an insignificant amount of loans for
which payments are current, but the borrowers are experiencing financial
difficulties. These loans are subject to constant management attention, and
their classification is reviewed on a monthly basis.

Summary of Loan Loss Experience

        The following table summarizes loan balances at the end of each period
and average loans based on daily average balances for 1998, 1997, and 1996;
changes in the allowance for possible loan losses arising from loans charged off
and recoveries on loans previously charged off by loan category; and additions
to the allowance which have been charged to expense (in thousands of dollars):

<TABLE>
<CAPTION>
                                             1998         1997         1996  
                                           --------     --------     --------
<S>                                        <C>          <C>          <C>     
Amount of loans outstanding
  at end of period                         $ 28,058     $ 28,435     $ 28,926
                                           ========     ========     ========

Average amount                             $ 28,548     $ 27,797     $ 27,635
                                           ========     ========     ========
</TABLE>




                                     - 10 -

<PAGE>   11


Item 1.  Business (continued)

Allowance for Possible Loan Losses
(In thousands of dollars)

<TABLE>
<CAPTION>
                                                                        Year Ended December 31,    
                                                             -------------------------------------------
                                                               1998              1997             1996  
                                                             --------          --------         --------

<S>                                                          <C>               <C>              <C>     
Beginning balance                                            $    600          $    614         $    624
Provision charged against income                                   -                 -                - 
                                                             --------          --------         --------
                                                                  600               614              624
                                                             --------          --------         --------
Charge-offs:
  Commercial, financial and
    agricultural loans                                             -                 (1)              -
  Real estate mortgage loans                                       -                 -                -
  Real estate construction loans                                   -                 -                -
  Installment loans                                               (15)              (16)             (18)
                                                             --------          --------         --------
    Total charge-offs                                             (15)              (17)             (18)
                                                             --------          --------         --------

Recoveries:
  Commercial, financial and agricultural loans                     -                 -                 5
  Real estate mortgage loans                                       -                 -                 1
  Real estate construction loans                                   -                 -                -
  Installment loans                                                11                 3                2
                                                             --------          --------         --------
                                                                   11                 3                8
                                                             --------          --------         --------

Net (charge-offs) recoveries                                       (4)              (14)             (10)
                                                             --------          --------         --------

Ending balance                                               $    596          $    600         $    614
                                                             ========          ========         ========

Ratio of net (charge-offs) recoveries
  during the period to average loans
  outstanding during the period                                 (.01)%            (.05)%           (.04)%
                                                             =======           =======          =======
</TABLE>

        The allowance for possible loan losses has been allocated according to
the amount deemed to be reasonably necessary to provide for the possibility of
losses being incurred within the following categories of loans at the date
indicated:

Allocation of Allowance for Possible Loan Losses
(In thousands of dollars)

<TABLE>
<CAPTION>
                                                                December 31, 1998                    December 31, 1997  
                                                         ----------------------------         ----------------------------
                                                                           % of Loans                          % of Loans
                                                                          Outstanding                         Outstanding
                                                                            to Total                            to Total
                                                         Allowance           Loans            Allowance          Loans   
                                                         ---------        -----------         ---------       ------------
<S>                                                      <C>                   <C>            <C>                  <C>   
Commercial, financial and
  agricultural loans                                     $     135             27.32%         $     218            26.55%
Real estate construction                                         1               .18                  5             1.27
Real estate mortgage loans                                     272             54.75                 97            54.66
Installment loans                                              188             17.75                280            17.52
                                                         ---------           -------          ---------          -------

                                                         $     596            100.00%         $     600           100.00%
                                                         =========           =======          =========          =======
</TABLE>



                                     - 11 -

<PAGE>   12


Item 1.  Business (continued)

Allocation of Allowance for Possible Loan Losses (continued)
(In thousands of dollars)

<TABLE>
<CAPTION>
                                                                                                December 31, 1996  
                                                                                              ---------------------------
                                                                                                               % of Loans
                                                                                                              Outstanding
                                                                                                                to Total
                                                                                              Allowance          Loans   
                                                                                              ---------       -----------
<S>                                                                                           <C>                  <C>   
Commercial, financial and
  agricultural loans                                                                          $     201            25.71%
Real estate construction                                                                              3              .98
Real estate mortgage loans                                                                          146            56.28
Installment loans                                                                                   264            17.03
                                                                                              ---------          -------

                                                                                              $     614           100.00%
                                                                                              =========          =======
</TABLE>

Deposits

        The average amount of deposits, using daily average balances for 1998,
1997, and 1996, is summarized for the periods indicated in the following table
(in thousands of dollars):

<TABLE>
<CAPTION>
                                                                                         Year Ended December 31,    
                                                                              -------------------------------------------
                                                                                1998              1997             1996  
                                                                              --------          --------         --------

<S>                                                                           <C>               <C>              <C>     
Non-interest bearing demand deposits                                          $ 19,070          $ 16,846         $ 15,530
Interest-bearing demand deposits                                                11,104            11,752           11,510
Savings deposits                                                                 9,223             8,374            8,597
Time deposits                                                                   19,747            19,003           17,659
                                                                              --------          --------         --------

                                                                              $ 59,144          $ 55,975         $ 53,296
                                                                              ========          ========         ========
</TABLE>


Return on equity and assets

        The ratio of Net Income to Average Shareholders' Equity and to Average
Total Assets, and certain other ratios, are as follows:

<TABLE>
<CAPTION>
                                                                                        Year Ended December 31,    
                                                                              -------------------------------------------
                                                                                1998              1997             1996  
                                                                              --------          --------         --------
<S>                                                                               <C>               <C>              <C>  
Percentage of net income to:
  Average total assets                                                            1.47%             1.47%            1.70%
  Average shareholders' equity                                                   11.27%            11.70%           14.32%

Percentage of dividends declared per
  common share to net income per
  common share                                                                   14.76%            13.92%           11.56%

Percentage of average shareholders'
  equity to daily average total assets                                           13.06%            12.58%           11.88%
</TABLE>




                                     - 12 -

<PAGE>   13


Item 1.  Business (continued)

Short-Term Borrowing

        The Company's short-term borrowing and the average interest rate thereon
at the end of the last three years, are as follows (in thousands of dollars):

<TABLE>
<CAPTION>
                                                                                         Year Ended December 31,    
                                                                              -------------------------------------------
                                                                                1998              1997             1996  
                                                                              --------          --------         --------

<S>                                                                           <C>               <C>              <C>    
    Balance at December 31                                                    $     -           $     -          $     -
    Weighted average interest rate at
      year end                                                                      - %               - %              - %
    Maximum amount outstanding at any
      month's end                                                             $     -           $     -          $    950
    Average amount outstanding during
      the year                                                                $     29          $     -          $     66
    Weighted average interest rate
      during the year                                                             6.90%               - %            4.55%
</TABLE>


Item 2.  Properties

        The main office of the Company and the Bank are presently located at 328
East Landry Street, Opelousas, Louisiana, in the downtown business district. The
Bank leases four branch sites. The building in which the main office is located
is free of all mortgages.

        For information with respect to the Company obligations under its lease
commitments, see Note 12 to the Consolidated Financial Statements, which are
incorporated herein by reference under Item 8.


Item 3.  Legal Proceedings

        The Company is not involved in any legal actions; however, there are
presently pending by the Bank a number of legal proceedings. It is the opinion
of management that the resulting liability, if any, from these actions and other
pending claims will not materially affect the consolidated financial statements.


Item 4.  Submission of Matters to a Vote of Security Holders

         No matters were submitted during the fourth quarter of the fiscal year
covered by this report to a vote of security holders, through the solicitation
of proxies or otherwise.




                                     - 13 -

<PAGE>   14



                                     PART II

Item 5.  Market for Registrant's Common Stock and Related Security Holder 
         Matters

                       MARKET PRICE AND DIVIDENDS DECLARED

<TABLE>
<CAPTION>
                                                                                                         Dividends
               Year              Quarter                     High                   Low                  Per Share 
               ----              -------                    ------                ------                 ---------

               <S>               <C>                        <C>                   <C>                       <C> 
               1998              First                      $   53                $   53                    $  -
                                 Second                         55                    55                       -
                                 Third                          57                    57                       -
                                 Fourth                         60                    30                     1.25

               1997              First                      $   30                $   20                    $  -
                                 Second                         30                    30                       -
                                 Third                          30                    30                       -
                                 Fourth                         53                    30                     1.10
</TABLE>



        Note: The primary market area for American Bancorp, Inc.'s common stock
is the Opelousas, Louisiana area with American Bank and Trust Company acting as
registrar and transfer agent. There were approximately 540 shareholders of
record at December 31, 1998.

        Source of market price - American Bank & Trust Company acts as the
transfer agent for the Company. The stock is thinly traded and the price ranges
are based on stated sales price to the transfer agent, which does not represent
all sales.


RESTRICTIONS ON CASH DIVIDENDS PAYABLE BY THE REGISTRANT:

        The only source of funds by the Company to pay dividends is dividends
paid by the Subsidiary Bank, the payment of which is restricted by applicable
federal and state statutes.

        Federal bank regulatory authorities have authority under the Financial
Institutions Supervisory Act to prohibit a bank from engaging in an unsafe or
unsound practice. The payment of a dividend by the Bank could, depending upon
the financial condition of the Bank and other factors be deemed an unsafe or
unsound practice.

        Applicable Louisiana law prohibits a state bank subsidiary from paying a
dividend if its surplus remaining after payment of the dividend would be less
than half the aggregate par value of its outstanding stock. In addition, a state
bank subsidiary is required to obtain the prior approval of the Commissioner of
Financial Institutions of Louisiana before declaring or paying a dividend in a
given year if the total of all dividends declared or paid during that year would
exceed the total of its net profits for that year combined with the net profits
from the immediately preceding year.






                                     - 14 -

<PAGE>   15



Item 6.  Selected Financial Data

        The information called for by Item 6 is included in Registrant's Annual
Report on page 5 in the Section titled "Summary of Operations for the Last Five
Years" and is incorporated herein by reference.


Item 7.  Management's Discussion and Analysis of Financial Condition and Results
         of Operations

        The information called for by Item 7 is included in the Registrant's
Annual Report in the section titled "Management's Discussion and Analysis of
Operations" and is incorporated herein by reference.


Item 8.  Financial Statements and Supplementary Data

        The following consolidated financial statements of the Registrant and
its subsidiary included on pages 28 through 56 in the Annual Report are
incorporated herein by reference:

        Consolidated Balance Sheets - December 31, 1998 and 1997
        Consolidated Statements of Income - Years Ended December 31, 1998,
            1997, and 1996
        Consolidated Statements of Shareholders' Equity - Years Ended
            December 31, 1998, 1997, and 1996
        Consolidated Statements of Cash Flows - Years Ended December 31, 1998,
            1997, and 1996
        Notes to Consolidated Financial Statements


Item 9.  Disagreements in Accounting and Financial Disclosure

        There have been no disagreements with an independent accountant on any
matter of accounting principles or practice, financial disclosure, auditing
scope or procedure.


                                    PART III

Item 10. Directors and Executive Officers

        With the exception of identification of executive officers of the
Company, the information called for by Item 10 is omitted pursuant to General
Instruction G(3) and is included in Registrant's definitive Proxy Statement
filed pursuant to Section 14(a). Executive officers of the Company are
identified in Item 1, "Executive Officer," included in Part I of this report.


Item 11. Management Remuneration and Transactions

        The information called for by this item is included in Registrant's
definitive Proxy Statement filed pursuant to Section 14(a) of the Securities
Exchange Act of 1934 and is incorporated herein by reference.



                                     - 15 -

<PAGE>   16



Item 12. Security Ownership of Certain Beneficial Owners and Management

        The information called for by this item is included in Registrant's
definitive Proxy Statement filed pursuant to Section 14(a) of the Securities
Exchange Act of 1934 and is incorporated herein by reference.


Item 13. Certain Relationships and Related Transactions

        The information called for by this item is included in Registrant's
definitive Proxy Statement filed pursuant to Section 14(a) of the Securities
Exchange Act of 1934 and is incorporated herein by reference.


                                     PART IV

Item 14. Exhibits, Financial Statement Schedules, and Reports on Form 8-K

              (a)     1. Financial Statements

                      The following consolidated financial statements of
                      American Bancorp, Inc. and Subsidiary, included in pages
                      28 through 56 of the Registrant's Annual Report are
                      incorporated by reference in Item 8:

                         Consolidated Balance Sheets - December 31, 1998 and 
                              1997
                         Consolidated Statements of Income - Years Ended 
                              December 31, 1998, 1997 and 1996
                         Consolidated Statements of Shareholders' Equity - Years
                              Ended December 31, 1998, 1997 and 1996
                         Consolidated Statements of Cash Flows - Years Ended
                              December 31, 1998, 1997 and 1996
                         Notes to Consolidated Financial Statements


              (a)     2. Financial Statement Schedules

                      The Schedules to the consolidated financial statements
                      required by Article 9, and all other schedules to the
                      financial statements of the Registrant required by Article
                      9 of Regulation S-X are not required under the related
                      instructions or are inapplicable and therefore have been
                      omitted.


              (a)     3. Exhibits

                      (13)    1998 Annual Report to Shareholders
                      (22)    Proxy Statement for Annual Meeting of Shareholders
                              to be held on April 14, 1999
                      (23)    Consent of Independent Auditors
                      (27)    Financial data schedule





                                     - 16 -

<PAGE>   17



Item 14. Exhibits, Financial Statement Schedules, and Reports on Form 8-K 
         (continued)

              (b)             Reports on Form 8-K

                      None


              (c)             Exhibits

                      The response to this portion of Item 14 is submitted as a
                      separate section of this report.


              (d)             Financial Statement Schedules

                      The response to this portion of Item 14 is submitted as a
                      separate section of this report.




                                     - 17 -

<PAGE>   18



                                   Signatures

        Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

                                         American Bancorp, Inc.
                                         (Registrant)



                                         By:  /s/ Salvador L. Diesi, Sr.      
                                            -----------------------------------
                                              Salvador L. Diesi, Sr., Chairman
                                                of the Board of the Company
                                                and the Bank; President of
                                                the Company and the Bank

                                         Date: March 10, 1999                 
                                              ---------------------------------


        Pursuant to the requirements of the Securities Exchange Act of 1934,
this report has been signed by the following persons on behalf of the Registrant
and in the capacities and on the dates indicated.



/s/ Salvador L. Diesi, Sr.               /s/ Jasper J. Artall                  
------------------------------------     --------------------------------------
Salvador L. Diesi, Sr., Chairman of      Jasper J. Artall, Director
  the Board of the Company and the
  Bank; President of the Company
  and the Bank

Date: March 10, 1999                     Date: March 10, 1999                  
      ------------------------------           --------------------------------



/s/ Ronald J. Lashute                    /s/ Walter J. Champagne, Jr.          
------------------------------------     --------------------------------------
Ronald J. Lashute, Executive Vice-       Walter J. Champagne, Jr., Director
  President and Chief Executive 
  Officer of the Bank; Secretary/
  Treasurer of the Company

Date: March 10, 1999                     Date: March 10, 1999                  
      ------------------------------          ---------------------------------



                                         /s/ J. C. Diesi                       
                                         --------------------------------------
                                         J. C. Diesi, Director

                                         Date: March 10, 1999                  
                                              ---------------------------------






                                     - 18 -

<PAGE>   19


                                  EXHIBIT INDEX



<TABLE>
<CAPTION>
       Exhibit
       Number                      Description            
       -------                     -----------

<S>                 <C>                               
         13.1       1998 Annual Report to shareholders of American Bancorp, Inc.

         22.1       1998 Proxy Statement for annual meeting of shareholders.

         23.1       Consent of Independent Auditors.

         27.1       Financial Data Schedule.
</TABLE>