20 ILCS 663/15

No tax credit claimed under this Act shall be refundable or saleable on the open market. Tax credits earned by a partnership, limited liability company, S corporation, or other "pass-through" entity may be allocated to the partners, members, or shareholders of that entity for their direct use in accordance with the provisions of any agreement among the partners, members, or shareholders. Any amount of tax credit that the taxpayer, or partner, member, or shareholder thereof, is prohibited from claiming in a taxable year may be carried forward to any of the taxpayer's 5 subsequent taxable years.