Notwithstanding the provisions of paragraph (1) , a nonresident (other than, for taxable years ending on or after December 31, 2011, a nonresident required to withhold tax under Section 709.5) whose Illinois income tax liability under subsections (a) , (b) , (c) , and (d) of Section 201 of this Act is paid in full after taking into account the credits allowed under subsection (f) of this Section or allowed under Section 709.5 of this Act shall not be required to file a return under this subsection (a) .
For taxable years ending on or after December 31, 1987, corporate members (other than Subchapter S corporations) of the same unitary business group making this subsection (e) election are not required to have the same taxable year. For taxable years ending on or after December 31, 1993, taxpayers that are corporations (other than Subchapter S corporations) and that are members of the same unitary business group shall be treated as one taxpayer for purposes of any original return, amended return which includes the same taxpayers of the unitary group which joined in filing the original return, extension, claim for refund, assessment, collection and payment and determination of the group's tax liability under this Act.
For taxable years ending prior to December 31, 2014, the Department may by regulation also permit such composite returns to include the income tax owed by Illinois residents attributable to their income from partnerships, Subchapter S corporations, insurance businesses organized under a Lloyds plan of operation, or limited liability companies that are treated as partnership under Section 1501(a) (16) of this Act, in which case such Illinois residents will be permitted to claim credits on their individual returns for their shares of the composite tax payments. This paragraph of subsection (f) applies to taxable years ending on or after December 31, 1987 and ending prior to December 31, 2014.
For taxable years ending on or after December 31, 1999, the Department may, by regulation, permit any persons transacting an insurance business organized under a Lloyds plan of operation to file composite returns reflecting the income of such persons allocable to Illinois and the tax rates applicable to such persons under Section 201 and to make composite tax payments and shall, by regulation, also provide that the income and apportionment factors attributable to the transaction of an insurance business organized under a Lloyds plan of operation by any person joining in the filing of a composite return shall, for purposes of allocating and apportioning income under Article 3 of this Act and computing net income under Section 202 of this Act, be excluded from any other income and apportionment factors of that person or of any unitary business group, as defined in subdivision (a) (27) of Section 1501, to which that person may belong. For taxable years ending on or after December 31, 2008, every nonresident shall be allowed a credit against his or her liability under subsections (a) and (b) of Section 201 for any amount of tax reported on a composite return and paid on his or her behalf under this subsection (f) . Residents (other than persons transacting an insurance business organized under a Lloyds plan of operation) may claim a credit for taxes reported on a composite return and paid on their behalf under this subsection (f) only as permitted by the Department by rule.
35 ILCS 5/502