35 ILCS 30/20
Any qualified taxpayer, referred to in this Section as the assignor, may sell, assign, convey, or otherwise transfer tax credits allowed and earned under this Act. The taxpayer acquiring the credits, referred to in this Section as the assignee, may use the amount of the acquired credits to offset up to 100% of its income tax liability for either the taxable year in which the qualified rehabilitation plan was first placed into service or the taxable year in which such acquisition was made. Unused credit amounts claimed by the assignee may be carried forward for up to 10 years or carried back for up to 3 years, except that all credits must be claimed within 10 years after the tax year in which the qualified rehabilitation plan was first placed into service and may not be carried back to a tax year prior to the tax year in which the credit was issued. The assignor shall enter into a written agreement with the assignee establishing the terms and conditions of the agreement and shall perfect the transfer by notifying the Department in writing within 90 calendar days after the effective date of the transfer and shall provide any information as may be required by the Department to administer and carry out the provisions of this Section. If credits that have been transferred are subsequently reduced, adjusted, or recaptured, in whole or in part, by the Department, the Department of Revenue, or any other applicable government agency, only the original qualified taxpayer that was awarded the credits, and not any subsequent assignee of the credits, shall be held liable to repay any amount of such reduction, adjustment, or recapture of the credits.
35 ILCS 30/20