(35 ILCS 5/1501) (from Ch. 120, par. 15-1501)
    Sec. 1501. Definitions.
    (a) In general. When used in this Act, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof:
        (1) Business income. The term "business income" means all income that may be treated as
    
apportionable business income under the Constitution of the United States. Business income is net of the deductions allocable thereto. Such term does not include compensation or the deductions allocable thereto. For each taxable year beginning on or after January 1, 2003, a taxpayer may elect to treat all income other than compensation as business income. This election shall be made in accordance with rules adopted by the Department and, once made, shall be irrevocable.
        (1.5) Captive real estate investment trust:
            (A) The term "captive real estate investment trust" means a corporation, trust, or
        
association:
                (i) that is considered a real estate investment trust for the taxable year under
            
Section 856 of the Internal Revenue Code;
                (ii) the certificates of beneficial interest or shares of which are not
            
regularly traded on an established securities market; and
                (iii) of which more than 50% of the voting power or value of the beneficial
            
interest or shares, at any time during the last half of the taxable year, is owned or controlled, directly, indirectly, or constructively, by a single corporation.
            (B) The term "captive real estate investment trust" does not include:
                (i) a real estate investment trust of which more than 50% of the voting power or
            
value of the beneficial interest or shares is owned or controlled, directly, indirectly, or constructively, by:
                    (a) a real estate investment trust, other than a captive real estate
                
investment trust;
                    (b) a person who is exempt from taxation under Section 501 of the Internal
                
Revenue Code, and who is not required to treat income received from the real estate investment trust as unrelated business taxable income under Section 512 of the Internal Revenue Code;
                    (c) a listed Australian property trust, if no more than 50% of the voting
                
power or value of the beneficial interest or shares of that trust, at any time during the last half of the taxable year, is owned or controlled, directly or indirectly, by a single person;
                    (d) an entity organized as a trust, provided a listed Australian property
                
trust described in subparagraph (c) owns or controls, directly or indirectly, or constructively, 75% or more of the voting power or value of the beneficial interests or shares of such entity; or
                    (e) an entity that is organized outside of the laws of the United States and
                
that satisfies all of the following criteria:
                        (1) at least 75% of the entity's total asset value at the close of its
                    
taxable year is represented by real estate assets (as defined in Section 856(c)(5)(B) of the Internal Revenue Code, thereby including shares or certificates of beneficial interest in any real estate investment trust), cash and cash equivalents, and U.S. Government securities;
                        (2) the entity is not subject to tax on amounts that are distributed to
                    
its beneficial owners or is exempt from entity-level taxation;
                        (3) the entity distributes at least 85% of its taxable income (as
                    
computed in the jurisdiction in which it is organized) to the holders of its shares or certificates of beneficial interest on an annual basis;
                        (4) either (i) the shares or beneficial interests of the entity are
                    
regularly traded on an established securities market or (ii) not more than 10% of the voting power or value in the entity is held, directly, indirectly, or constructively, by a single entity or individual; and
                        (5) the entity is organized in a country that has entered into a tax
                    
treaty with the United States; or
                (ii) during its first taxable year for which it elects to be treated as a real
            
estate investment trust under Section 856(c)(1) of the Internal Revenue Code, a real estate investment trust the certificates of beneficial interest or shares of which are not regularly traded on an established securities market, but only if the certificates of beneficial interest or shares of the real estate investment trust are regularly traded on an established securities market prior to the earlier of the due date (including extensions) for filing its return under this Act for that first taxable year or the date it actually files that return.
            (C) For the purposes of this subsection (1.5), the constructive ownership rules
        
prescribed under Section 318(a) of the Internal Revenue Code, as modified by Section 856(d)(5) of the Internal Revenue Code, apply in determining the ownership of stock, assets, or net profits of any person.
            (D) For the purposes of this item (1.5), for taxable years ending on or after August
        
16, 2007, the voting power or value of the beneficial interest or shares of a real estate investment trust does not include any voting power or value of beneficial interest or shares in a real estate investment trust held directly or indirectly in a segregated asset account by a life insurance company (as described in Section 817 of the Internal Revenue Code) to the extent such voting power or value is for the benefit of entities or persons who are either immune from taxation or exempt from taxation under subtitle A of the Internal Revenue Code.
        (2) Commercial domicile. The term "commercial domicile" means the principal place from
    
which the trade or business of the taxpayer is directed or managed.
        (3) Compensation. The term "compensation" means wages, salaries, commissions and any
    
other form of remuneration paid to employees for personal services.
        (4) Corporation. The term "corporation" includes associations, joint-stock companies,
    
insurance companies and cooperatives. Any entity, including a limited liability company formed under the Illinois Limited Liability Company Act, shall be treated as a corporation if it is so classified for federal income tax purposes.
        (5) Department. The term "Department" means the Department of Revenue of this State.
        (6) Director. The term "Director" means the Director of Revenue of this State.
        (7) Fiduciary. The term "fiduciary" means a guardian, trustee, executor, administrator,
    
receiver, or any person acting in any fiduciary capacity for any person.
        (8) Financial organization.
            (A) The term "financial organization" means any bank, bank holding company, trust
        
company, savings bank, industrial bank, land bank, safe deposit company, private banker, savings and loan association, building and loan association, credit union, currency exchange, cooperative bank, small loan company, sales finance company, investment company, or any person which is owned by a bank or bank holding company. For the purpose of this Section a "person" will include only those persons which a bank holding company may acquire and hold an interest in, directly or indirectly, under the provisions of the Bank Holding Company Act of 1956 (12 U.S.C. 1841, et seq.), except where interests in any person must be disposed of within certain required time limits under the Bank Holding Company Act of 1956.
            (B) For purposes of subparagraph (A) of this paragraph, the term "bank" includes (i)
        
any entity that is regulated by the Comptroller of the Currency under the National Bank Act, or by the Federal Reserve Board, or by the Federal Deposit Insurance Corporation and (ii) any federally or State chartered bank operating as a credit card bank.
            (C) For purposes of subparagraph (A) of this paragraph, the term "sales finance
        
company" has the meaning provided in the following item (i) or (ii):
                (i) A person primarily engaged in one or more of the following businesses: the
            
business of purchasing customer receivables, the business of making loans upon the security of customer receivables, the business of making loans for the express purpose of funding purchases of tangible personal property or services by the borrower, or the business of finance leasing. For purposes of this item (i), "customer receivable" means:
                    (a) a retail installment contract or retail charge agreement within the
                
meaning of the Sales Finance Agency Act, the Retail Installment Sales Act, or the Motor Vehicle Retail Installment Sales Act;
                    (b) an installment, charge, credit, or similar contract or agreement arising
                
from the sale of tangible personal property or services in a transaction involving a deferred payment price payable in one or more installments subsequent to the sale; or
                    (c) the outstanding balance of a contract or agreement described in
                
provisions (a) or (b) of this item (i).
                A customer receivable need not provide for payment of interest on deferred
            
payments. A sales finance company may purchase a customer receivable from, or make a loan secured by a customer receivable to, the seller in the original transaction or to a person who purchased the customer receivable directly or indirectly from that seller.
                (ii) A corporation meeting each of the following criteria:
                    (a) the corporation must be a member of an "affiliated group" within the
                
meaning of Section 1504(a) of the Internal Revenue Code, determined without regard to Section 1504(b) of the Internal Revenue Code;
                    (b) more than 50% of the gross income of the corporation for the taxable
                
year must be interest income derived from qualifying loans. A "qualifying loan" is a loan made to a member of the corporation's affiliated group that originates customer receivables (within the meaning of item (i)) or to whom customer receivables originated by a member of the affiliated group have been transferred, to the extent the average outstanding balance of loans from that corporation to members of its affiliated group during the taxable year do not exceed the limitation amount for that corporation. The "limitation amount" for a corporation is the average outstanding balances during the taxable year of customer receivables (within the meaning of item (i)) originated by all members of the affiliated group. If the average outstanding balances of the loans made by a corporation to members of its affiliated group exceed the limitation amount, the interest income of that corporation from qualifying loans shall be equal to its interest income from loans to members of its affiliated groups times a fraction equal to the limitation amount divided by the average outstanding balances of the loans made by that corporation to members of its affiliated group;
                    (c) the total of all shareholder's equity (including, without limitation,
                
paid-in capital on common and preferred stock and retained earnings) of the corporation plus the total of all of its loans, advances, and other obligations payable or owed to members of its affiliated group may not exceed 20% of the total assets of the corporation at any time during the tax year; and
                    (d) more than 50% of all interest-bearing obligations of the affiliated
                
group payable to persons outside the group determined in accordance with generally accepted accounting principles must be obligations of the corporation.
            This amendatory Act of the 91st General Assembly is declaratory of existing law.
            (D) Subparagraphs (B) and (C) of this paragraph are declaratory of existing law and
        
apply retroactively, for all tax years beginning on or before December 31, 1996, to all original returns, to all amended returns filed no later than 30 days after the effective date of this amendatory Act of 1996, and to all notices issued on or before the effective date of this amendatory Act of 1996 under subsection (a) of Section 903, subsection (a) of Section 904, subsection (e) of Section 909, or Section 912. A taxpayer that is a "financial organization" that engages in any transaction with an affiliate shall be a "financial organization" for all purposes of this Act.
            (E) For all tax years beginning on or before December 31, 1996, a taxpayer that
        
falls within the definition of a "financial organization" under subparagraphs (B) or (C) of this paragraph, but who does not fall within the definition of a "financial organization" under the Proposed Regulations issued by the Department of Revenue on July 19, 1996, may irrevocably elect to apply the Proposed Regulations for all of those years as though the Proposed Regulations had been lawfully promulgated, adopted, and in effect for all of those years. For purposes of applying subparagraphs (B) or (C) of this paragraph to all of those years, the election allowed by this subparagraph applies only to the taxpayer making the election and to those members of the taxpayer's unitary business group who are ordinarily required to apportion business income under the same subsection of Section 304 of this Act as the taxpayer making the election. No election allowed by this subparagraph shall be made under a claim filed under subsection (d) of Section 909 more than 30 days after the effective date of this amendatory Act of 1996.
            (F) Finance Leases. For purposes of this subsection, a finance lease shall be
        
treated as a loan or other extension of credit, rather than as a lease, regardless of how the transaction is characterized for any other purpose, including the purposes of any regulatory agency to which the lessor is subject. A finance lease is any transaction in the form of a lease in which the lessee is treated as the owner of the leased asset entitled to any deduction for depreciation allowed under Section 167 of the Internal Revenue Code.
        (9) Fiscal year. The term "fiscal year" means an accounting period of 12 months ending
    
on the last day of any month other than December.
        (9.5) Fixed place of business. The term "fixed place of business" has the same meaning
    
as that term is given in Section 864 of the Internal Revenue Code and the related Treasury regulations.
        (10) Includes and including. The terms "includes" and "including" when used in a
    
definition contained in this Act shall not be deemed to exclude other things otherwise within the meaning of the term defined.
        (11) Internal Revenue Code. The term "Internal Revenue Code" means the United States
    
Internal Revenue Code of 1954 or any successor law or laws relating to federal income taxes in effect for the taxable year.
        (11.5) Investment partnership.
            (A) For tax years ending before December 31, 2023, the term "investment partnership"
        
means any entity that is treated as a partnership for federal income tax purposes that meets the following requirements:
                (i) no less than 90% of the partnership's cost of its total assets consists of
            
qualifying investment securities, deposits at banks or other financial institutions, and office space and equipment reasonably necessary to carry on its activities as an investment partnership;
                (ii) no less than 90% of its gross income consists of interest,
            
dividends, and gains from the sale or exchange of qualifying investment securities; and
                (iii) the partnership is not a dealer in qualifying investment securities.
            (A-5) For tax years ending on or after December 31, 2023, the term "investment
        
partnership" means any entity that is treated as a partnership for federal income tax purposes that meets the following requirements:
                (i) no less than 90% of the partnership's cost of its total assets consists of
            
qualifying investment securities, deposits at banks or other financial institutions, and office space and equipment reasonably necessary to carry on its activities as an investment partnership; and
                (ii) no less than 90% of its gross income consists of interest, dividends, gains
            
from the sale or exchange of qualifying investment securities, and the distributive share of partnership income from lower-tier partnership interests meeting the definition of qualifying investment security under subparagraph (B)(xiii); for the purposes of this subparagraph (ii), "gross income" does not include income from partnerships that are operating at a federal taxable loss.
            (B) For purposes of this paragraph (11.5), the term "qualifying investment
        
securities" (other than, for tax years ending on or after December 31, 2023, securities with respect to which the taxpayer is required to apply the rules of Internal Revenue Code Section 475(a)) includes all of the following:
                (i) common stock, including preferred or debt securities convertible into common
            
stock, and preferred stock;
                (ii) bonds, debentures, and other debt securities;
                (iii) foreign and domestic currency deposits secured by federal, state, or local
            
governmental agencies;
                (iv) mortgage or asset-backed securities secured by federal, state, or local
            
governmental agencies;
                (v) repurchase agreements and loan participations;
                (vi) foreign currency exchange contracts and forward and futures contracts on
            
foreign currencies;
                (vii) stock and bond index securities and futures contracts and other similar
            
financial securities and futures contracts on those securities;
                (viii) options for the purchase or sale of any of the securities, currencies,
            
contracts, or financial instruments described in items (i) to (vii), inclusive;
                (ix) regulated futures contracts;
                (x) commodities (not described in Section 1221(a)(1) of the Internal Revenue
            
Code) or futures, forwards, and options with respect to such commodities, provided, however, that any item of a physical commodity to which title is actually acquired in the partnership's capacity as a dealer in such commodity shall not be a qualifying investment security;
                (xi) derivatives;
                (xii) a partnership interest in another partnership that is an investment
            
partnership; and
                (xiii) for tax years ending on or after December 31, 2023, a partnership
            
interest that, in the hands of the partnership, qualifies as a security within the meaning of subsection (a)(1) of Subchapter 77b of Chapter 2A of Title 15 of the United States Code.
        (12) Mathematical error. The term "mathematical error" includes the following types of
    
errors, omissions, or defects in a return filed by a taxpayer which prevents acceptance of the return as filed for processing:
            (A) arithmetic errors or incorrect computations on the return or supporting
        
schedules;
            (B) entries on the wrong lines;
            (C) omission of required supporting forms or schedules or the omission of the
        
information in whole or in part called for thereon; and
            (D) an attempt to claim, exclude, deduct, or improperly report, in a manner directly
        
contrary to the provisions of the Act and regulations thereunder any item of income, exemption, deduction, or credit.
        (13) Nonbusiness income. The term "nonbusiness income" means all income other than
    
business income or compensation.
        (14) Nonresident. The term "nonresident" means a person who is not a resident.
        (15) Paid, incurred and accrued. The terms "paid", "incurred" and "accrued" shall be
    
construed according to the method of accounting upon the basis of which the person's base income is computed under this Act.
        (16) Partnership and partner. The term "partnership" includes a syndicate, group, pool,
    
joint venture or other unincorporated organization, through or by means of which any business, financial operation, or venture is carried on, and which is not, within the meaning of this Act, a trust or estate or a corporation; and the term "partner" includes a member in such syndicate, group, pool, joint venture or organization.
        The term "partnership" includes any entity, including a limited liability company formed
    
under the Illinois Limited Liability Company Act, classified as a partnership for federal income tax purposes.
        The term "partnership" does not include a syndicate, group, pool, joint venture, or
    
other unincorporated organization established for the sole purpose of playing the Illinois State Lottery.
        (17) Part-year resident. The term "part-year resident" means an individual who became a
    
resident during the taxable year or ceased to be a resident during the taxable year. Under Section 1501(a)(20)(A)(i) residence commences with presence in this State for other than a temporary or transitory purpose and ceases with absence from this State for other than a temporary or transitory purpose. Under Section 1501(a)(20)(A)(ii) residence commences with the establishment of domicile in this State and ceases with the establishment of domicile in another State.
        (18) Person. The term "person" shall be construed to mean and include an individual, a
    
trust, estate, partnership, association, firm, company, corporation, limited liability company, or fiduciary. For purposes of Section 1301 and 1302 of this Act, a "person" means (i) an individual, (ii) a corporation, (iii) an officer, agent, or employee of a corporation, (iv) a member, agent or employee of a partnership, or (v) a member, manager, employee, officer, director, or agent of a limited liability company who in such capacity commits an offense specified in Section 1301 and 1302.
        (18A) Records. The term "records" includes all data maintained by the taxpayer, whether
    
on paper, microfilm, microfiche, or any type of machine-sensible data compilation.
        (19) Regulations. The term "regulations" includes rules promulgated and forms prescribed
    
by the Department.
        (20) Resident. The term "resident" means:
            (A) an individual (i) who is in this State for other than a temporary or transitory
        
purpose during the taxable year; or (ii) who is domiciled in this State but is absent from the State for a temporary or transitory purpose during the taxable year;
            (B) the estate of a decedent who at his or her death was domiciled in this State;
            (C) a trust created by a will of a decedent who at his death was domiciled in this
        
State; and
            (D) an irrevocable trust, the grantor of which was domiciled in this State at the
        
time such trust became irrevocable. For purpose of this subparagraph, a trust shall be considered irrevocable to the extent that the grantor is not treated as the owner thereof under Sections 671 through 678 of the Internal Revenue Code.
        (21) Sales. The term "sales" means all gross receipts of the taxpayer not allocated
    
under Sections 301, 302 and 303.
        (22) State. The term "state" when applied to a jurisdiction other than this State means
    
any state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, any Territory or Possession of the United States, and any foreign country, or any political subdivision of any of the foregoing. For purposes of the foreign tax credit under Section 601, the term "state" means any state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, and any territory or possession of the United States, or any political subdivision of any of the foregoing, effective for tax years ending on or after December 31, 1989.
        (23) Taxable year. The term "taxable year" means the calendar year, or the fiscal year
    
ending during such calendar year, upon the basis of which the base income is computed under this Act. "Taxable year" means, in the case of a return made for a fractional part of a year under the provisions of this Act, the period for which such return is made.
        (24) Taxpayer. The term "taxpayer" means any person subject to the tax imposed by this
    
Act.
        (25) International banking facility. The term international banking facility shall have
    
the same meaning as is set forth in the Illinois Banking Act or as is set forth in the laws of the United States or regulations of the Board of Governors of the Federal Reserve System.
        (26) Income Tax Return Preparer.
            (A) The term "income tax return preparer" means any person who prepares for
        
compensation, or who employs one or more persons to prepare for compensation, any return of tax imposed by this Act or any claim for refund of tax imposed by this Act. The preparation of a substantial portion of a return or claim for refund shall be treated as the preparation of that return or claim for refund.
            (B) A person is not an income tax return preparer if all he or she does is
                (i) furnish typing, reproducing, or other mechanical assistance;
                (ii) prepare returns or claims for refunds for the employer by whom he or she is
            
regularly and continuously employed;
                (iii) prepare as a fiduciary returns or claims for refunds for any person; or
                (iv) prepare claims for refunds for a taxpayer in response to any notice of
            
deficiency issued to that taxpayer or in response to any waiver of restriction after the commencement of an audit of that taxpayer or of another taxpayer if a determination in the audit of the other taxpayer directly or indirectly affects the tax liability of the taxpayer whose claims he or she is preparing.
        (27) Unitary business group.
            (A) The term "unitary business group" means a group of persons related through
        
common ownership whose business activities are integrated with, dependent upon and contribute to each other. The group will not include those members whose business activity outside the United States is 80% or more of any such member's total business activity; for purposes of this paragraph and clause (a)(3)(B)(ii) of Section 304, business activity within the United States shall be measured by means of the factors ordinarily applicable under subsections (a), (b), (c), (d), or (h) of Section 304 except that, in the case of members ordinarily required to apportion business income by means of the 3 factor formula of property, payroll and sales specified in subsection (a) of Section 304, including the formula as weighted in subsection (h) of Section 304, such members shall not use the sales factor in the computation and the results of the property and payroll factor computations of subsection (a) of Section 304 shall be divided by 2 (by one if either the property or payroll factor has a denominator of zero). The computation required by the preceding sentence shall, in each case, involve the division of the member's property, payroll, or revenue miles in the United States, insurance premiums on property or risk in the United States, or financial organization business income from sources within the United States, as the case may be, by the respective worldwide figures for such items. Common ownership in the case of corporations is the direct or indirect control or ownership of more than 50% of the outstanding voting stock of the persons carrying on unitary business activity. Unitary business activity can ordinarily be illustrated where the activities of the members are: (1) in the same general line (such as manufacturing, wholesaling, retailing of tangible personal property, insurance, transportation or finance); or (2) are steps in a vertically structured enterprise or process (such as the steps involved in the production of natural resources, which might include exploration, mining, refining, and marketing); and, in either instance, the members are functionally integrated through the exercise of strong centralized management (where, for example, authority over such matters as purchasing, financing, tax compliance, product line, personnel, marketing and capital investment is not left to each member).
            (B) In no event, for taxable years ending prior to December 31, 2017, shall any
        
unitary business group include members which are ordinarily required to apportion business income under different subsections of Section 304 except that for tax years ending on or after December 31, 1987 this prohibition shall not apply to a holding company that would otherwise be a member of a unitary business group with taxpayers that apportion business income under any of subsections (b), (c), (c-1), or (d) of Section 304. If a unitary business group would, but for the preceding sentence, include members that are ordinarily required to apportion business income under different subsections of Section 304, then for each subsection of Section 304 for which there are two or more members, there shall be a separate unitary business group composed of such members. For purposes of the preceding two sentences, a member is "ordinarily required to apportion business income" under a particular subsection of Section 304 if it would be required to use the apportionment method prescribed by such subsection except for the fact that it derives business income solely from Illinois. As used in this paragraph, for taxable years ending before December 31, 2017, the phrase "United States" means only the 50 states and the District of Columbia, but does not include any territory or possession of the United States or any area over which the United States has asserted jurisdiction or claimed exclusive rights with respect to the exploration for or exploitation of natural resources. For taxable years ending on or after December 31, 2017, the phrase "United States", as used in this paragraph, means only the 50 states, the District of Columbia, and any area over which the United States has asserted jurisdiction or claimed exclusive rights with respect to the exploration for or exploitation of natural resources, but does not include any territory or possession of the United States.
            (C) Holding companies.
                (i) For purposes of this subparagraph, a "holding company" is a corporation
            
(other than a corporation that is a financial organization under paragraph (8) of this subsection (a) of Section 1501 because it is a bank holding company under the provisions of the Bank Holding Company Act of 1956 (12 U.S.C. 1841, et seq.) or because it is owned by a bank or a bank holding company) that owns a controlling interest in one or more other taxpayers ("controlled taxpayers"); that, during the period that includes the taxable year and the 2 immediately preceding taxable years or, if the corporation was formed during the current or immediately preceding taxable year, the taxable years in which the corporation has been in existence, derived substantially all its gross income from dividends, interest, rents, royalties, fees or other charges received from controlled taxpayers for the provision of services, and gains on the sale or other disposition of interests in controlled taxpayers or in property leased or licensed to controlled taxpayers or used by the taxpayer in providing services to controlled taxpayers; and that incurs no substantial expenses other than expenses (including interest and other costs of borrowing) incurred in connection with the acquisition and holding of interests in controlled taxpayers and in the provision of services to controlled taxpayers or in the leasing or licensing of property to controlled taxpayers.
                (ii) The income of a holding company which is a member of more than one unitary
            
business group shall be included in each unitary business group of which it is a member on a pro rata basis, by including in each unitary business group that portion of the base income of the holding company that bears the same proportion to the total base income of the holding company as the gross receipts of the unitary business group bears to the combined gross receipts of all unitary business groups (in both cases without regard to the holding company) or on any other reasonable basis, consistently applied.
                (iii) A holding company shall apportion its business income under the subsection
            
of Section 304 used by the other members of its unitary business group. The apportionment factors of a holding company which would be a member of more than one unitary business group shall be included with the apportionment factors of each unitary business group of which it is a member on a pro rata basis using the same method used in clause (ii).
                (iv) The provisions of this subparagraph (C) are intended to clarify existing
            
law.
            (D) If including the base income and factors of a holding company in more than one
        
unitary business group under subparagraph (C) does not fairly reflect the degree of integration between the holding company and one or more of the unitary business groups, the dependence of the holding company and one or more of the unitary business groups upon each other, or the contributions between the holding company and one or more of the unitary business groups, the holding company may petition the Director, under the procedures provided under Section 304(f), for permission to include all base income and factors of the holding company only with members of a unitary business group apportioning their business income under one subsection of subsections (a), (b), (c), or (d) of Section 304. If the petition is granted, the holding company shall be included in a unitary business group only with persons apportioning their business income under the selected subsection of Section 304 until the Director grants a petition of the holding company either to be included in more than one unitary business group under subparagraph (C) or to include its base income and factors only with members of a unitary business group apportioning their business income under a different subsection of Section 304.
            (E) If the unitary business group members' accounting periods differ, the common
        
parent's accounting period or, if there is no common parent, the accounting period of the member that is expected to have, on a recurring basis, the greatest Illinois income tax liability must be used to determine whether to use the apportionment method provided in subsection (a) or subsection (h) of Section 304. The prohibition against membership in a unitary business group for taxpayers ordinarily required to apportion income under different subsections of Section 304 does not apply to taxpayers required to apportion income under subsection (a) and subsection (h) of Section 304. The provisions of this amendatory Act of 1998 apply to tax years ending on or after December 31, 1998.
        (28) Subchapter S corporation. The term "Subchapter S corporation" means a corporation
    
for which there is in effect an election under Section 1362 of the Internal Revenue Code, or for which there is a federal election to opt out of the provisions of the Subchapter S Revision Act of 1982 and have applied instead the prior federal Subchapter S rules as in effect on July 1, 1982.
        (30) Foreign person. The term "foreign person" means any person who is a nonresident
    
individual who is a national or citizen of a country other than the United States and any nonindividual entity, regardless of where created or organized, whose business activity outside the United States is 80% or more of the entity's total business activity.
    (b) Other definitions.
        (1) Words denoting number, gender, and so forth, when used in this Act, where not
    
otherwise distinctly expressed or manifestly incompatible with the intent thereof:
            (A) Words importing the singular include and apply to several persons, parties or
        
things;
            (B) Words importing the plural include the singular; and
            (C) Words importing the masculine gender include the feminine as well.
        (2) "Company" or "association" as including successors and assigns. The word "company"
    
or "association", when used in reference to a corporation, shall be deemed to embrace the words "successors and assigns of such company or association", and in like manner as if these last-named words, or words of similar import, were expressed.
        (3) Other terms. Any term used in any Section of this Act with respect to the
    
application of, or in connection with, the provisions of any other Section of this Act shall have the same meaning as in such other Section.
(Source: P.A. 102-1030, eff. 5-27-22; 103-9, eff. 6-7-23.)