UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year-ended December 31, 20042005

or

For the transition period from            to            

Commission File Number 0-10967

FIRST MIDWEST BANCORP, INC.

(Exact name of registrant as specified in its charter)

300 Park Blvd.,One Pierce Place, Suite 400, P.O. Box 4591500

Itasca, Illinois 60143-9768

(Address of principal executive offices) (zip code)

Registrant’s telephone number, including area code: (630) 875-7450

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

Securities registered pursuant to Section 12(g) of the Act:

Title of each class:

Indicate by check mark whether the issuer is a well-known seasoned issuer as defined in Rule 405 of the Securities Act of 1933.    Yes  x    No  ¨.

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    Yes  ¨    No  x.

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.    Yesx    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.x¨.

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer (as defined in Rule 12b-2 of the Exchange Act).    YesLarge accelerated filer  x    NoAccelerated filer  ¨    Non-accelerated filer  ¨.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x.

The aggregate market value of the registrant’s outstanding voting common stock held by non-affiliates on June 30, 2004,2005, determined using a per share closing price on that date of $35.21,$35.08, as quoted on The Nasdaq Stock Market, was $1,521,111,189.

$1,478,199,847.

At March 3, 2005February 27, 2006 there were 45,744,53345,442,134 shares of common stock, $.01 par value, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of Registrant’s Proxy Statement for the 20052006 Annual Stockholders’ Meeting - - Part III

FORM 10-K

FORM 10-K

TABLE OF CONTENTS

PART I

ITEM 1. BUSINESS

First Midwest Bancorp, Inc.

First Midwest Bancorp, Inc. (the “Company”) is a bank holding company incorporated in Delaware in 1982 for the purpose of becoming a holding company registered under the Bank Holding Company Act of 1956, as amended (the “Act”). The Company is one of Illinois’ largest publicly traded banking companies with assets of $6.9$7.2 billion at year-end 20042005 and is headquartered in the Chicago suburb of Itasca, Illinois.

The Company operates two wholly owned subsidiaries: First Midwest Bank (the “Bank”), employing 1,6301,622 full-time equivalent employees at December 31, 2004,2005, and First Midwest Insurance Company, which is largely inactive.

The Company has responsibility for the overall conduct, direction, and performance of its subsidiaries. The Company provides various services, establishes Company-wide policies and procedures, and provides other resources as needed, including capital.

Subsidiaries

At December 31, 2004,2005, the Bank had $6.8$7.2 billion in total assets, $5.0$5.2 billion in total deposits, and operated 6768 banking offices primarily in suburban metropolitan Chicago.

The Bank is engaged in commercial and retail banking and offers a broad range of lending, depository, and related financial services, including accepting deposits; commercial and industrial, consumer, and real estate lending; collections; trust and investment management services; cash management services; safe deposit box operations; and other banking services tailored for consumer, commercial and industrial, and public or governmental customers. The Bank also provides an electronic banking center on the Internet atwww.firstmidwest.com, which enables Bank customers to perform banking transactions and provides information about Bank products and services to the general public.

The Bank is comprised of two divisions, aBank’s operations are divided into sales division and a support division.functions. The sales divisionfunction is structured along commercial and retail product lines, and the support divisionfunction provides corporate, administrative, and support services.

The Bank has one wholly-owned subsidiary,operates two wholly owned subsidiaries: FMB Investment Corporation and First Midwest Investments, Inc., which currently is inactive.

FMB Investment Corporation whichis a Delaware corporation established in 1998. FMB Investment Corporation manages investment securities, principally state and municipal obligations, and provides corporate management services to its wholly-ownedwholly owned subsidiary First MidwestFMB Investment Trust, whicha Maryland business trust also established in 1998. FMB Investment Trust manages real estate loans.

loans originated by the Bank. FMB Investment Trust has elected to be taxed as a Real Estate Investment Trust for federal income tax purposes.

First Midwest Insurance Company operates as a reinsurer of credit life, accident, and health insurance sold through the Bank, primarily in conjunction with its consumer lending operations, and is largely inactive.

On December 12, 2005, the Company announced the execution of a definitive agreement to acquire Bank Calumet, Inc. (“Bank Calumet”) and its wholly owned subsidiary bank for $307 million in cash. Bank Calumet is a bank holding company headquartered in Hammond, Indiana with $1.2 billion in assets and 30 branches located predominantly in Lake County, Indiana and the contiguous Illinois counties of Cook and Will. In February 2006, the transaction was approved by the Board of Governors of the Federal Reserve Board (the “Federal Reserve”) and by Bank Calumet’s shareholders. The Company expects to complete this acquisition early in the second quarter of 2006, subject to customary closing conditions, including the approval of the Department of Financial Institutions of the State of Indiana.

The Company believes that Bank Calumet represents an excellent opportunity to expand its franchise in the southeast Chicago metropolitan area. The Company looks forward to building upon the long-standing relationships that Bank Calumet has developed in its 73 years of banking service to these dynamic markets and expects that Bank Calumet’s conservative policies, diversified lending base, and community banking approach will fit well with the Company’s established business model.

Competition

Illinois and the metropolitan Chicago area are highly competitive markets for banking and related financial services. Competition is based on a number of factors, including:including interest rates charged on loans and paid on deposits; the ability to attract new deposits; the scope and type of banking and financial services offered; the hours during which business can be conducted; the location of bank branches and ATMs; the availability, ease of use, and range of banking services on the Internet; the availability of related services; and a variety of additional services such as investment management, fiduciary, and brokerage services. Within the geographic areaareas it serves, the Bank competes with other banking institutionsbanks and savings and loan associations, personal loan and finance companies, and credit unions. In addition, the Bank competes for deposits with money market mutual funds and investment brokers on the basis of interest rates offered and available products. Recently, theThe competition for banking customers intensifiedremains intense as a number of local and out-of-state banking institutions announced plans forhave engaged in large-scale branch office expansion in the suburban Chicago markets, and certain local banks were acquired by larger local and national financial institutions.

whether through acquisition or establishment of de novo branches.

In providing investment advisory services, the Bank also competes with retail and discount stockbrokers, investment advisors, mutual funds, insurance companies, and, to a lesser extent, financial institutions for investment management clients. Factors influencing this type of competition generally involve the variety of products and services that can be offered to clients and the performance of funds under management. With the proliferation of investment management service companies, such as mutual funds and discount brokerage services, competitionCompetition for investment management services comes from financial service providers both within and outside of the geographic areas in which the Bank maintains offices.

Offering a broad array of products and services at competitive prices is an important element in competing for customers. The Company differentiates itself, however, byin the way it systematically assessingassesses a customer’s specific financial needs, sellingsells products and services identified in such assessment, and providingprovides its high quality services and products. The Company believes thisits approach as well asand its knowledge and commitment to the communities in which the Bank is located isare the most important aspectaspects in retaining and expanding its customer base.

Supervision and Regulation

The Company and its subsidiaries are subject to regulation and supervision by various governmental regulatory authorities including the Board of Governors of the Federal Reserve, Board, the Federal Deposit Insurance Corporation (the “FDIC”), the Illinois CommissionerDepartment of BanksFinancial and Real Estate CompaniesProfessional Regulation (the “Commissioner of Illinois”“IDFRP”), and the Arizona Department of Insurance. Financial institutions and their holding companies are extensively regulated under Federal and state law. The effect of such statutes, regulations, and policies can be significant and cannot be predicted with a high degree of certainty.

Federal and state laws and regulations generally applicable to financial institutions, such as the Company and its subsidiaries, regulate, among other things, the scope of business, investments, reserves against deposits, capital levels relative to operations, the nature and amount of collateral for loans, the establishment of branches, mergers, consolidations, and dividends. This supervision and regulation is intended primarily for the protection of the FDIC’s bank (the “BIF”) and savings association (the “SAIF”) insurance funds and the depositors, rather than the stockholders, of a financial institution.

The following references to material statutes and regulations affecting the Company and its subsidiaries are brief summaries thereof and are qualified in their entirety by reference to such statutes and regulations. Any change in applicable law or regulations may have a material effect on the business or operations of the Company and its subsidiaries. The operations of the Company and the Bank may also be affected by changes in the policies of various regulatory authorities. The Company cannot accurately predict the nature or the extent of the effects that any such changes would have on its business and earnings.

Bank Holding Company Act of 1956, as amended (the “Act”)

Generally, the Act governs the acquisition and control of banks and non-bankingnonbanking companies by bank holding companies. A bank holding company is subject to regulation under the Act and is required to register with the Federal Reserve under the Act. A bank holding company is required by the Act to file an annual report of its operations and such additional information as the Federal Reserve may require and is subject, along with its subsidiaries, to examination by the Federal Reserve. The Federal Reserve has jurisdiction to regulate the terms of certain debt issues of bank holding companies, including the authority to impose reserve requirements.

The acquisition of 5% or more of the voting shares of any bank or bank holding company requires the prior approval of the Federal Reserve and is subject to applicable Federal law, including the Riegle-Neal Interstate Banking and Branching Efficiency Act of 1994 (“Riegle Neal”), for interstate transactions, and possible state law limitations as well. The Federal Reserve evaluates acquisition applications based upon, among other things, antitrust, safetycompetitive factors, supervisory factors, adequacy of financial and soundness,managerial resources, and banking and community service considerations.

The Act also prohibits, with certain exceptions, a bank holding company from acquiring direct or indirect ownership or control of more than 5% of the voting shares of any “non banking”“nonbanking” company unless the non-bankingnonbanking activities are found by the Federal Reserve to be “so closely related to banking . . . as to be a proper incident thereto.” Under current regulations of the Federal Reserve, a bank holding company and its nonbank subsidiaries are permitted, among other activities, to engage in such banking-related business ventures as consumer finance, equipment leasing, data processing, mortgage banking, financial and investment advice, and securities brokerage services. The Act does not place territorial restrictions on the activities of a bank holding company or its nonbank subsidiaries.

Federal law prohibits acquisition of “control” of a bank or bank holding company without prior notice to certain Federal bank regulators. “Control” is defined in certain cases as the acquisition of as little as 10% of the outstanding shares. Furthermore, under certain circumstances, a bank holding company may not be able to purchase its own stock, where the gross consideration will equal 10% or more of the company’s net worth, without obtaining approval of the Federal Reserve. Under the Federal Reserve Act, banks and their subsidiaries (including bank holding companies) are subject to certain requirements and restrictions when dealing with each other (subsidiary transactions)(affiliate transactions including transactions with their bank holding company). The Company is also subject to the provisions of the Illinois Bank Holding Company Act.

Interstate Banking

Bank holding companies are permitted in any state to acquire banks and bank holding companies in any state and to be acquired, subject to the requirements of Riegle Neal, and in some cases, applicable state law.

Under Riegle Neal, adequately capitalized and managed bank holding companies may be permitted by the Federal Reserve to acquire control of a bank in any state. States, however, may prohibit acquisitions of banks that have not been in existence for at least five years. The Federal Reserve is prohibited from approving an application for acquisition if the applicant controls more than 10% of the total amount of deposits of insured depository institutions nationwide. In addition, interstate acquisitions may also be subject to statewide concentration limits.

The Federal Reserve would be prohibited from approving an application if, prior to consummation, the proposed acquirer controls any insured depository institution or branch in the home state of the target bank, and the applicant, following consummation of an acquisition, would control 30% or more of the total amount of deposits of insured depository institutions in that state. This legislation also provides that the provisions on concentration limits do not affect the authority of any state to limit or waive the percentage of the total amount of deposits in the state which would be held or controlled by any bank or bank holding company to the extent the application of this limitation does not discriminate against out-of-state institutions.

Interstate branching under Riegle Neal permits banks to merge across state lines, thereby creating a bank headquartered in one state with branches in other states. Approval of interstate bank mergers is subject to certain conditions, including: adequate capitalization, adequate management, Community Reinvestment Act compliance, deposit concentration limits (as set forth above), compliance with Federal and state antitrust laws, and compliance with applicable state consumer protection laws. An interstate merger transaction may involve the acquisition of a branch without the acquisition of the bank only if the law of the state in which the branch is located permits out-of-state banks to acquire a branch of a bank in that state without acquiring the bank. Following the consummation of an interstate transaction, the resulting bank may establish additional branches at any location where any bank involved in the transaction could have established a branch under applicable Federal or state law, if such bank had not been a party to the merger transaction.

Riegle Neal became effective on June 1, 1997 and allowed each state, prior to the effective date, the opportunity to “opt out,” thereby prohibiting interstate branching within that state. Of the two states in which the Bank is located (Illinois and Iowa), neither has adopted legislation to “opt out” of the interstate merger provisions. Furthermore, pursuant to Riegle Neal, a bank is able to add new branches in a state in which it does not already have banking operations if such state enacts a law permitting such de novo branching, or, if the state allows acquisition of branches, subject to applicable state requirements.

Illinois law allows de novo banking with other states that allow Illinois banks to branch de novo in those states.

The effects on the Company of the changes in interstate banking and branching laws cannot be accurately predicted, but it is likely that there will be increased competition from national and regional banking firms headquartered outside of Illinois which establish banks in Illinois. Likewise, the Company may establish branches in reciprocity states (such as Indiana) on a de novo basis.

Illinois Banking Law

The Illinois Banking Act (“IBA”) governs the activities of the Company,Bank, an Illinois state banking corporation. The IBA defines the powers and permissible activities of an Illinois state chartered bank, prescribes corporate governance standards, imposes approval requirements on mergers of state banks, prescribes lending limits, and provides for the examination of state banks by the Commissioner of Illinois.IDFPR. The Banking on Illinois Act (“BIA”) became effective in mid-1999 and amended the IBA to provide a potential wide range of new activities for Illinois state chartered banks, including the Bank. The provisions of the BIA are to be construed liberally in order to create a favorable business climate for banks in Illinois. The main features of the BIA are to expand bank powers through a new “wild card” provision authorizing Illinois chartered banks to offer virtually any product or service that any bank or thrift may offer anywhere in the country, subject to certain safety and soundness considerations and prior notification to the Commissioner of IllinoisIDFPR and the FDIC. Previously, in addition to enumerated powers stated in the IBA, state banks could engage in any activity authorized or permitted to be conducted by a national bank. Management of the Bank remains aware of the favorable environment created by the BIA and will consider the opportunities that may become available to the Bank as a result of such legislation.

The Bank is subject to a variety of Federal and state laws and regulations governing its operations. For example, deposit activities are subject, among other things, to the Federal Truth in Savings Act and the Illinois Consumer Deposit Account Act. Federal law, including the Electronic Funds Transfer Act, and state laws also govern electronic banking transactions. Trust activities of the Bank are subject to the Illinois Corporate Fiduciaries Act. Loans made by the Bank are subject to applicable provisions of the Illinois Interest Act, the Federal Truth in Lending Act, and the Illinois Financial Services Development Act.

The Bank is subject to a variety of other laws and regulations concerning equal credit opportunity, fair lending, customer privacy, fair credit reporting, and community reinvestment. The Bank currently holds an “outstanding” rating for community reinvestment activity, the highest available.

The Commissioner of Illinois has adopted predatory lending regulations. These regulations apply to “high cost” mortgages which are defined as mortgages which exceed a specified interest rate or are assessed points in excess of a specified minimum. Once any of these thresholds is reached, the regulations impose certain restrictions on the lender, including: obligating the lender to verify the borrower’s ability to repay the loan based on the borrower’s income and debt obligations; prohibiting deceptive refinancing known as loan flipping where a lender refinances existing loans; charging additional points and fees, without any financial benefit to the consumer; prohibiting the financing of a single premium credit insurance policy; prohibiting the financing of points and fees in excess of 6% of the total loan amount; limiting the size and interval of balloon payments; and limiting prepayment penalties that could be charged to consumers. These regulations also require the lender to make certain disclosures to borrowers who are seeking high cost mortgages. The regulations apply to all state licensed financial institutions making residential loans in Illinois. The regulations also require lenders to file with the Commissioner of Illinois semi-annual reports on mortgage loans, including information relating to defaults and foreclosures.

The Illinois legislature has also considered the adoption of legislation aimed at curbing what some legislators and consumer-oriented advocacy groups consider to be predatory lending practices by some mortgage brokers and other lenders active in the State of Illinois. “Predatory” lending consists of fraudulent and deceptive sales practices that occur when borrowers are pressured into taking out loans they do not need or cannot afford. Since neither the Company nor the Bank engages in such practices, it is unlikely that any legislation adopted in Illinois to combat this perceived problem would have an impact on the Company or the Bank, other than the creation of additional reporting requirements.

As an Illinois banking corporation controlled by a bank holding company, the Bank is subject to the rules regarding change of control in the Act and the Federal Deposit Insurance Act and the regulations promulgated thereunder and is also subject to the rules regarding change in control of Illinois banks contained in the IBA.

IBA and the Illinois Bank Holding Company Act.

The Bank is subject to Sections 22(h), 23A, and 23B of the Federal Reserve Act, which restrict or impose requirements on financial transactions between federally insured depository institutions and subsidiaryaffiliated companies. The statute limits credit transactions between a bank and its executive officers and its subsidiaries, prescribes terms and conditions for bank subsidiaryaffiliate transactions deemed to be consistent with safe and sound banking practices, requires arms-length transactions between subsidiaries,affiliates, and restricts the types of collateral security permitted in connection with a bank’s extension of credit to a subsidiary.

affiliates.

Gramm-Leach-Bliley Act of 1999

The enactment of the Gramm-Leach-Bliley Act of 1999 (“GLB Act”) swept away large parts of a regulatory framework that had its origins in the Depression Era of the 1930s. Effective March 11, 2000, new opportunities became available for banks, other depository institutions, insurance companies, and securities firms to enter into combinations that permit a single financial services organization to offer customers a more comprehensive array of financial products and services. To further this goal, the GLB Act amends section 4 of the Act providing a new regulatory framework applicable to a financial holding company (“FHC”), which has as its primary regulator the Federal Reserve. Functional regulation of the FHC’s subsidiaries will be conducted by their primary functional regulators. Pursuant to the GLB Act, bank holding companies, subsidiary depository institutions thereof, and foreign banks electing to qualify as aan FHC must be “well managed,” “well capitalized,” and rated at least satisfactory under the Community Reinvestment Act in order to engage in new financial activities.

An FHC may engage in securities and insurance activities and other activities that are deemed financial in nature or incidental to a financial activity under the GLB Act.Act, such as merchant banking activities. While aware of the flexibility of the FHC statute, the Company has, for the time being, decided not to become aan FHC, but will continue to follow the reception given FHCs in the marketplace. The activities of bank holding companies that are not FHCs will continue to be regulated by and limited to activities permissible under the Act.

The GLB Act also prohibits a financial institution from disclosing non-public personal information about a consumer to nonaffiliatedunaffiliated third parties, unless the institution satisfies various disclosure requirements and the consumer has not elected to opt out of the disclosure. Under the GLB Act, a financial institution must provide its customers with a notice of its privacy policies and practices. The Federal Reserve, the FDIC, and other financial regulatory agencies have issued regulations implementing notice requirements and restrictions on a financial institution’s ability to disclose non-public personal information about consumers to nonaffiliatedunaffiliated third parties.

The Company is also subject to certain state laws that limit the use and distribution of non-public personal information, both to subsidiaries, affiliates, and unaffiliated entities.

The GLB Act is expected, in time, to alter the competitive landscape of the product markets presently served by the Company. Companies that are presently engaged primarily in insurance activities or securities activities are now permitted to acquire banks and bank holding companies, such as the Company. The Company may, in the future, face increased competition from a broader range of larger, more diversified financial companies.

Bank Secrecy Act and USA Patriot Act

In 1970, Congress enacted the Currency and Foreign Transactions Reporting Act, commonly known as the Bank Secrecy Act (the “BSA”). The BSA requires financial institutions to maintain records of certain customers and currency transactions and to report certain domestic and foreign currency transactions, which have a high degree of usefulness in criminal, tax, or regulatory investigations or proceedings. Under this law, financial institutions are required to develop a BSA compliance program.

On October 26, 2001, the President signed into law comprehensive anti-terrorism legislation known as the USA Patriot Act. Title III of the USA Patriot Act requires financial institutions, including the Company and the Bank, to help prevent, detect, and prosecute those involved in international money laundering and the financing of terrorism. The Department of the Treasury has adopted additional requirements to further implement Title III.

Under these regulations, a mechanism has been established for law enforcement officials to communicate names of suspected terrorists and money launderers to financial institutions to enable financial institutions to promptly locate accounts and transactions involving those suspects. Financial institutions receiving names of suspects must search their account and transaction records for potential matches and report positive results to the U.S. Department of the Treasury Financial Crimes Enforcement Network (“FinCEN”). Each financial institution must designate a point of contact to receive information requests. These regulations outline how financial institutions can share information concerning suspected terrorist and money laundering activity with other financial institutions under the protection of a statutory safe harbor if each financial institution notifies FinCEN of its intent to share information.

The Department of the Treasury has also adopted regulations intended to prevent money laundering and terrorist financing through correspondent accounts maintained by U.S. financial institutions on behalf of foreign banks. Financial institutions are required to take reasonable steps to ensure that they are not providing banking services directly or indirectly to foreign shell banks.

In addition, banks must have procedures in place to identify and verify the identity of the persons with whom they deal. The Company and the Bank have augmented their systems and procedures to accomplish compliance with these requirements. The Company and the Bank believe that the cost of compliance with Title III of the USA Patriot Act is not likely to be material to them.

In July 2004, the Company and the Bank entered into an agreement with the Federal Reserve and the Illinois Office of Banks and Real EstateIDFPR (the “Written Agreement”) to enhance its compliance with all applicable Federalfederal and state laws, rules, and regulations relating to anti-money laundering policies and procedures. To fully address allthe deficiencies cited deficiencies,in the Written Agreement, the Bank authored a written compliance plan and completed a compliance review of certain customer transactions since the date of the last prior satisfactory regulatory review. TheAs a result, the Bank has conducted a comprehensive review of policy, procedure, systems, and manpower addressing these important areasareas. The Bank successfully resolved the deficiencies cited, and expects that it will be deemed in compliance with this agreement.received a letter dated September 30, 2005 from the Federal Reserve Bank of Chicago and the IDFPR, which formally communicated the termination of the Written Agreement. The Company believes that this agreement willWritten Agreement did not have no negativea significant effect on itsthe Bank’s financial condition, liquidity, capital resources, or operations.

Capital Guidelines

The Federal Reserve and the other Federalfederal functional bank regulators have established risk-based capital guidelines to provide a framework for assessing the adequacy of the capital of national and state banks, thrifts, and their bank holding companies (collectively, “banking institutions”). These guidelines apply to all banking institutions, regardless of size, and are used in the examination and supervisory process as well as in the analysis of applications to be acted upon by the regulatory authorities. These guidelines require banking institutions to maintain capital based on the credit risk of their operations, both on and off-balance sheet.

The minimum capital ratios established by the guidelines are based on both Tier 1 and Total capital to total risk-based assets. In addition to the risk-based capital requirements, the Federal Reserve and the FDIC require banking institutions to maintain a minimum leveraged-capital ratio to supplement the risk-based capital guidelines. The Company and the Bank are “well capitalized” by these standards, the highest applicable ratings.

Dividends

The Company’s primary source of liquidity is dividend payments from the Bank. In addition to capital guidelines, the Bank is limited in the amount of dividends it can pay to the Company under the IBA. Under this law, the Bank is permitted to declare and pay dividends in amounts up to the amount of its accumulated net profits, provided that it retains in its surplus at least one-tenth of its net profits since the date of the declaration of its most recent dividend until those additions to surplus, in the aggregate, equal the paid-in capital of the Bank. The Bank may not, while it continues its banking business, pay dividends in excess of its net profits then on hand (after deductions for losses and bad debts). As of December 31, 2004,2005, the Bank could distribute dividends of approximately $19.7$32.0 million without approval from the Commissioner of Illinois.IDFPR. In addition, the Bank is limited in the amount of dividends it can pay under the Federal Reserve Act and Regulation H. For example, dividends cannot be paid that would constitute a withdrawal of capital,capital; dividends cannot be declared or paid if they exceed a bank’s undivided profits,profits; and a bank may not declare or pay a dividend greater than current year net income plus retained net income of the prior two years without Federal Reserve approval.

Since the Company is a legal entity, separate and distinct from the Bank, its dividends to stockholders are not subject to the bank dividend guidelines discussed above. The Commissioner of IllinoisIDFPR is authorized to determine, under certain circumstances relating to the financial condition of a bank or bank holding company, that the payment of dividends by the Company would be an unsafe or unsound practice and to prohibit payment thereof. The Federal Reserve has taken the position that dividends that would create pressure or undermine the safety and soundness of the subsidiary bank are inappropriate.

FDIC Insurance Premiums

The Bank’s deposits are predominantly insured through the BIF, with certain deposits held by the Bank insured through the SAIF, both of which are administered by the FDIC. As insurer, the FDIC imposes deposit insurance premiums and is authorized to conduct examinations of, and to require reporting by, FDIC-insured institutions. It also may prohibit any FDIC-insured institution from engaging in any activity the FDIC determines by regulation or order to pose a serious risk to the BIF or SAIF.

The FDIC’s deposit insurance premiums are assessed through a risk-based system under which all insured depository institutions are placed into one of nine categories and assessed insurance premiums on deposits based upon their level of capital and supervisory evaluation. For 2005,2006, the Bank will pay premium assessments on both its BIF and SAIF insured deposits in order to service the interest on the Financing Corporation (“FICO”) bond obligations which were used to finance the cost of “thrift bailouts” in the 1980’s. The FICO assessment rates for the first semi-annual period of 20052006 were set at $.0144$.0132 per $100 of insured deposits each for BIF and SAIF assessable deposits. These rates may be adjusted quarterly to reflect changes in assessment basis for the BIF and SAIF.

Where You Can Find More Information About First Midwest

The Company makes available, free of charge, on its website, http://www.firstmidwest.com, its annual report on Form 10-K, quarterly reports on Form 10-Q, and current reports on Form 8-K, as soon as reasonably practicable after those reports are electronically filed with or furnished to the Securities and Exchange Commission (“SEC”).

ITEM 1A. RISK FACTORS

The material risks and uncertainties that management believes affect the Company are described below. Before making an investment decision with respect to any of the Company’s securities, you should carefully consider the risks and uncertainties as described below together with all of the information included herein. The risks and uncertainties described below are not the only risks and uncertainties the Company faces. Additional risks and uncertainties not presently known or that are currently deemed immaterial also may have a material adverse effect on the Company’s results of operations and financial condition. If any of the following risks actually occur, the Company’s results of operations and financial condition could suffer, possibly materially. In that event, the trading price of the Company’s common stock or other securities could decline. The risks discussed below also include forward-looking statements, and actual results may differ substantially from those discussed or implied in these forward-looking statements.

Risks Related To The Company’s Business

Competition in the banking industry is intense.

Competition in the banking and financial services industry is intense. In its primary market areas, the Bank competes with other commercial banks, savings and loan associations, credit unions, finance companies, insurance companies, and brokerage and investment banking firms operating locally and elsewhere. Many of these competitors have substantially greater resources and lending limits than the Bank and may offer certain services that the Bank does not provide. The Company’s profitability depends upon the Bank’s continued ability to compete effectively in its market areas. A number of local and out-of-state banking institutions have engaged in large-scale branch office expansion in the suburban Chicago markets, through acquisition or establishment of de novo branches.

The Company operates in a heavily regulated environment.

The banking industry is heavily regulated. The banking business of the Company and the Bank are subject, in certain respects, to regulation by the Federal Reserve, the FDIC, the Office of the Comptroller of the Currency, the IDFPR, and the SEC. The Company’s success depends not only on competitive factors but also on state and federal regulations affecting banks and bank holding companies. The regulations are primarily intended to protect depositors, not stockholders or other security holders. The ultimate effect of recent and proposed changes to the regulation of the financial institution industry cannot be predicted. Regulations now affecting the Company may be modified at any time, and there is no assurance that such modifications, if any, will not adversely affect the Company’s business.

Changes in the policies of monetary authorities could adversely affect the Company’s profitability.

The Company’s results of operations are affected by credit policies of monetary authorities, particularly the Federal Reserve. The instruments of monetary policy employed by the Federal Reserve include open market operations in United States government securities, changes in the discount rate or the federal funds rate on bank borrowings, and changes in reserve requirements against bank deposits. Changes in these policies could adversely affect the Company’s profitability. For example, changes impacting the Company’s cost of funds could reduce net interest income. No certainty can be given as to possible future changes in interest rates, deposit levels, loan demand, or the business and earnings of the Bank due to changing conditions in the national economy and in the money markets.

The Company’s business is concentrated in the Chicago metropolitan area, and a downturn in the economy of this area may adversely affect the Company’s business.

The Company’s success depends to a large degree on the general economic conditions of the geographic markets served by the Bank in the State of Illinois and, to a lesser extent, contiguous states. The local economic conditions in these areas have a significant impact on the generation of the Bank’s commercial, real estate commercial, and real estate construction loans; the ability of borrowers to repay these loans; and the value of the collateral securing these loans. Adverse changes in the economic conditions of the Chicago metropolitan area in general could also negatively impact the financial results of the Company’s operations and have a negative effect on its profitability. For example, these factors could lead to reduced interest income and an increase in the provision for loan losses.

A significant portion of the loans in the Company’s portfolio is secured by real estate. Most of these loans are secured by properties located in the Chicago metropolitan area. Negative conditions in the real estate markets where collateral for a mortgage loan is located could adversely affect the borrower’s ability to repay the loan and the value of the collateral securing the loan. Real estate values are affected by various factors, including changes in general or regional economic conditions, supply and demand for properties and governmental rules or policies.

Changes in the reserve for loan losses could affect profitability.

Managing the Company’s reserve for loan losses is based upon, among other things, (1) historical experience, (2) an evaluation of local and national economic conditions, (3) regular reviews of delinquencies and loan portfolio quality, (4) current trends regarding the volume and severity of past due and problem loans, (5) the existence and effect of concentrations of credit and (6) results of regulatory examinations. Based upon such factors, management makes various assumptions and judgments about the ultimate collectibility of the respective loan portfolios. Although the Company

believes that the reserve for loan losses is adequate, there can be no assurance that such reserve will prove sufficient to cover future losses. Future adjustments may be necessary if economic conditions change or adverse developments arise with respect to nonperforming or performing loans or if regulatory supervision changes. Material additions to the reserve for loan losses would result in a material decrease in the Company’s net income, and possibly its capital, and could result in the inability to pay dividends, among other adverse consequences.

The Company is a bank holding company, and its sources of funds are limited.

The Company is a bank holding company and its operations are primarily conducted by the Bank, which is subject to significant federal and state regulation. Cash available to pay dividends to stockholders of the Company is derived primarily, if not entirely, from dividends paid by the Bank. As a result, the Company’s ability to receive dividends or loans from its subsidiaries is restricted. At December 31, 2005, $32.0 million of the retained earnings of the Bank were available to pay dividends to the Company without regulatory approval. Dividend payments by the Bank to the Company in the future will require generation of future earnings by the Bank and could require regulatory approval if the proposed dividend is in excess of prescribed guidelines. Further, the Company’s right to participate in the assets of the Bank upon its liquidation, reorganization or otherwise will be subject to the claims of the Bank’s creditors, including depositors, which will take priority except to the extent the Company may be a creditor with a recognized claim. As of December 31, 2005, the Company’s subsidiaries had deposits and other liabilities of approximately $6.6 billion.

The Company is subject to environmental liability risk associated with lending activities.

A significant portion of the Company’s loan portfolio is secured by real property. During the ordinary course of business, the Company may foreclose on and take title to properties securing certain loans. In doing so, there is a risk that hazardous or toxic substances could be found on these properties. If hazardous or toxic substances are found, the Company may be liable for remediation costs, as well as for personal injury and property damage. Environmental laws may require the Company to incur substantial expenses and may materially reduce the affected property’s value or limit the Company’s ability to use or sell the affected property. In addition, future laws or more stringent interpretations or enforcement policies with respect to existing laws may increase the Company’s exposure to environmental liability.

Changes in interest rates could have an adverse effect on the Company’s income.

The Company’s financial performance depends to a significant extent upon its net interest income. Net interest income represents the difference between interest income and fees earned on interest-earning assets and interest expense incurred on interest-bearing liabilities. The Company’s net interest income is adversely affected if interest paid on deposits and borrowings increases faster than the interest earned on loans and investments. Changes in interest rates could also adversely affect the income of certain components of the Company’s noninterest income. For example, if mortgage interest rates increase, the demand for residential mortgage loans would likely decrease, which would have an adverse effect on the gain on the sale of mortgages.

Changes in the mix of the Company’s funding sources could have an adverse effect on the Company’s income. Over half of the Company’s funding sources are in lower-rate transactional deposit accounts. Market rate increases or competitive pricing could heighten the risk of moving to higher-rate funding sources, which would cause an adverse impact on the Company’s net income.

Future acquisitions may disrupt the Company’s business, dilute stockholder value, and adversely affect operating results.

The Company has grown by strategically acquiring banks or branches of other banks. The Company intends to continue to pursue acquisitions to supplement internal growth opportunities. Acquiring other banks or branches involves risks commonly associated with acquisitions, including:

Competition for acquisition candidates is intense.

Competition for acquisitions is intense. Numerous potential acquirors compete with the Company for most acquisition candidates, particularly on the basis of price to be paid. The Company may not be able to successfully identify and acquire suitable targets, which could slow the Company’s growth rate.

The Company’s continued pace of growth may require it to raise additional capital in the future, but that capital may not be available when it is needed.

The Company is required by federal and state regulatory authorities to maintain adequate levels of capital to support its operations. To the extent the Company continues to expand its asset base, primarily through loan growth, it will be required to support such growth by increasing its capital. In addition, the Company may be required to raise capital to support its acquisition strategy. Accordingly, the Company may need to raise capital in the future to support continued growth.

The Company’s ability to raise capital will depend on conditions in the capital markets, which are outside of its control, and on the Company’s financial performance. Accordingly, the Company cannot assure you of its ability to raise capital when needed or on favorable terms. If the Company cannot raise additional capital when needed, it will be subject to increased regulatory supervision and the imposition of restrictions on its growth and business. These could negatively impact the Company’s ability to further expand its operations through acquisitions or the establishment of additional branches and may result in increases in operating expenses and reductions in revenues that could harm its operating results.

Any reduction in the Company’s credit ratings could increase its financing costs.

The Company cannot give any assurance that its current credit ratings will remain in effect for any given period of time or that a rating will not be lowered or withdrawn entirely by a rating agency if, in its judgment, circumstances in the future so warrant. Any downgrade could increase the cost of borrowings or make it more difficult to obtain capital.

Our junior subordinated debentures have been assigned a rating by Standard & Poor’s Ratings Group, a division of The McGraw-Hill Companies, Inc. (“S&P”), of “BBB-” (stable outlook), by Moody’s Investors Service, Inc. (“Moody’s”) of “Baa2” (stable outlook), and by Fitch, Inc. (“Fitch”) of “BBB” (negative outlook). Fitch changed its outlook on our rating to negative on December 12, 2005.

The Company may experience greater than expected difficulties in integrating Bank Calumet into its operations.

The acquisition of Bank Calumet will involve the integration of two financial institutions that have previously operated independently of one another. The Company expects to realize cost savings together with other financial and operating benefits from the acquisition of Bank Calumet, but there can be no assurance as to when, or the extent to which, if at all, the Company will be able to realize these benefits. The Company may experience greater than expected difficulties in integrating Bank Calumet’s business, which could have an adverse effect on the Company’s ability to realize the expected benefits of the acquisition.

There are many things that could go wrong and adversely affect the business and profitability of the combined financial institution. The Company cannot predict the full range of post-acquisition problems that may occur. Some possible difficulties include:

The Company intends to finance a portion of the acquisition of Bank Calumet with a combination of the net proceeds of a common stock offering and the net proceeds from the issuance of subordinated debentures. The Company intends to finance the remainder of the purchase price with senior debt, which may take the form of senior debentures, a bank term loan, or a draw under the Company’s revolving credit facility. The Company’s final determination as to the mix of subordinated notes and senior debt will depend upon market conditions at the time of the offering of the debt securities among other considerations.

The Company cannot give any assurance that it will be able to consummate the Bank Calumet acquisition during the time frame currently contemplated or at all. In the event that the closing of the acquisition is delayed or does not occur, and if the common stock and debt securities have been issued, the Company will incur significant interest expense and stockholders will suffer dilution without the benefit of having acquired Bank Calumet.

The Company’s business is continually subject to technological change, and it may have fewer resources than its competition to continue to invest in technological improvements.

The banking and financial services industry continually undergoes rapid technological changes, with frequent introductions of new technology-driven products and services. In addition to better serving customers and thereby preserving its customer base, the effective use of technology increases efficiency and enables financial institutions to reduce costs. The Company’s future success will depend, in part, upon its ability to address the needs of its customers by using technology to provide products and services that enhance customer convenience, as well as create additional efficiencies in the Company’s operations. Many of the Company’s competitors have greater resources to invest in technological improvements, and the Company may not effectively implement new technology-driven products and services or do so as quickly, which could reduce its ability to effectively compete.

The Company’s information systems may experience an interruption or breach in security.

The Company relies heavily on communications and information systems to conduct its business. Any failure, interruption, or breach in security of these systems could result in failures or disruptions in the Company’s customer relationship management, general ledger, deposit, loan, or other systems. While the Company has policies and procedures designed to prevent or limit the effect of a failure, interruption, or security breach of its information systems, there can be no assurance that any such failures, interruptions or security breaches will not occur or, if they do occur, that they will be adequately addressed. The occurrence of any failures, interruptions or security breaches of the Company’s information systems could damage the Company’s reputation, result in a loss of customer business, subject the Company to additional regulatory scrutiny, or expose the Company to civil litigation and possible financial liability, any of which could have an adverse effect on the Company’s financial condition and results of operations.

The Company and its subsidiaries are subject to examinations and challenges by tax authorities.

In the normal course of business, the Company and its subsidiaries are routinely subject to examinations and challenges from federal and state tax authorities regarding the amount of taxes due in connection with investments made and the businesses in which we have engaged. Recently, federal and state taxing authorities have become increasingly aggressive in challenging tax positions taken by financial institutions. These tax positions may relate to tax compliance, sales and use, franchise, gross receipts, payroll, property, or income tax issues, including tax base, apportionment, and tax credit planning. The challenges made by tax authorities may result in adjustments to the timing or amount of taxable income or deductions or the allocation of income among tax jurisdictions. If any such challenges are made and are not resolved in the Company’s favor, they could have an adverse effect on the Company’s financial condition and results of operations.

Consumers and businesses may decide not to use banks to complete their financial transactions.

Technology and other changes are allowing parties to complete financial transactions that historically have involved banks at one or both ends of the transaction. For example, consumers can now pay bills and transfer funds directly without banks. The process of eliminating banks as intermediaries, known as disintermediation, could result in the loss of fee income, as well as the loss of customer deposits and income generated from those deposits.

Risks Related to the Securities Markets

Substantial sales of the Company’s common stock could cause its stock price to fall.

If stockholders sell substantial amounts of the Company’s common stock in the public market, the market price of the Company’s common stock could fall. Such sales also might make it more difficult for the Company to sell equity or equity-related securities in the future at a time and price that it deems appropriate.

The Company’s Restated Certificate of Incorporation, Amended and Restated By-Laws, and Amended and Restated Rights Agreement as well as certain banking laws may have an anti-takeover effect.

Provisions of the Company’s Restated Certificate of Incorporation and Amended and Restated By-laws, federal banking laws, including regulatory approval requirements, and the Company’s Amended and Restated Rights Plan could make it more difficult for a third party to acquire the Company, even if doing so would be perceived to be beneficial by the Company’s stockholders. The combination of these provisions effectively inhibits a non-negotiated merger or other business combination, which, in turn, could adversely affect the market price of the Company’s common stock.

The Company may issue additional securities, which could dilute the ownership percentage of holders of the Company’s common stock.

The Company may issue additional securities to raise additional capital or finance acquisitions or upon the exercise or conversion of outstanding options, and if it does, the ownership percentage of holders of the Company’s common stock could be diluted.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None. The Company did not receive written comments from the Commission during the 180 days preceding the end of the fiscal year to which this annual report relates.

ITEM 2. PROPERTIES

The executive offices of the Company, the Bank, and certain subsidiary operational facilities are located in a five-story16-story office building in Itasca, Illinois. The Company and the Bank currently occupy approximately 36,17960,933 square feet on the fourth floor of that building, which is leased through an unaffiliated third party.

As of December 31, 2004,2005, the Bank operated through 6768 bank branches and one operational facilities.facility. Of these, 12 are leased and the remaining 5557 are owned and not subject to any material liens. The banking offices are largely located in various communities primarily throughout Northernnorthern Illinois, principallyprimarily the Chicago metropolitan suburban area. At certain Bank locations, excess space is leased to third parties. The Bank also owns 9192 automated teller machines (ATMs), some of which are housed at a banking location and some of which are independently located. In addition, the Company owns other real property that, when considered individually or in the aggregate, is not material to the Company’s financial position.

The Company believes its facilities in the aggregate are suitable and adequate to operate its banking business. Additional information with respect to premises and equipment is presented in Note 76 of “Notes to Consolidated Financial Statements” commencing on page 59in Item 8 of this Form 10-K.

ITEM 3. LEGAL PROCEEDINGS

There are certain legal proceedings pending against the Company and its subsidiaries in the ordinary course of business at December 31, 2004.2005. The Company believes that any liabilities arising from these proceedings would not have a material adverse effect on the consolidated financial condition of the Company.

ITEM 4. SUBMISSIONSSUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

There were no items submitted to a vote of security holders during the fourth quarter of 2004.2005.

PART II

ITEM 5. MARKET FOR THE REGISTRANT’S COMMON EQUITY,

AND RELATED STOCKHOLDER MATTERS, AND

ISSUER PURCHASES OF EQUITY SECURITIES

The Company’s common stock is traded on The Nasdaq Stock Market under the symbol “FMBI.” As of December 31, 2004,2005, there were 2,6782,605 stockholders of record. The following table sets forth the closing common stock price, dividends per share, and book value per share during each quarter of 20042005 and 2003.2004.