(35 ILCS 5/503) (from Ch. 120, par. 5-503)

Sec. 503. Signing of returns and notices.

(a) Signature presumed authentic. The fact that an individual's name is signed to a return or notice shall be prima facie evidence for all purposes that such document was actually signed by such individual. If a return is prepared by an income tax return preparer for a taxpayer, that preparer shall sign the return as the preparer of that return and include his or her PTIN, as defined in the State Tax Preparer Oversight Act, on the return. If a return is transmitted to the Department electronically, the Department may presume that the electronic return originator has obtained and is transmitting a valid signature document pursuant to the rules promulgated by the Department for the electronic filing of tax returns, or the Department may authorize electronic return originators to maintain the signature documents and associated documentation, subject to the Department's right of inspection at any time without notice, rather than transmitting those documents to the Department, and the Department may process the return.

(b) Corporations. A return or notice required of a corporation shall be signed by the president, vice-president, treasurer or any other officer duly authorized so to act or, in the case of a limited liability company, by a manager or member. In the case of a return or notice made for a corporation by a fiduciary pursuant to the provisions of Section 502(b)(4), such fiduciary shall sign such document. The fact that an individual's name is signed to a return or notice shall be prima facie evidence that such individual is authorized to sign such document on behalf of the corporation.

(c) Partnerships. A return or notice of a partnership shall be signed by any one of the partners or, in the case of a limited liability company, by a manager or member. The fact that a partner's name is signed to a return or notice shall be prima facie evidence that such individual is authorized to sign such document on behalf of the partnership or limited liability company.

(d) Joint fiduciaries. A return or notice signed by one of two or more joint fiduciaries will comply with the requirements of this Act. The fact that a fiduciary's name is signed to such document shall be prima facie evidence that such fiduciary is authorized to sign such document on behalf of the person from whom it is required.

(e) Failure to sign a return. If a taxpayer fails to sign a return within 30 days after proper notice and demand for signature by the Department, the return shall be considered valid and any amount shown to be due on the return shall be deemed assessed. Any overpayment of tax shown on the face of an unsigned return shall be considered forfeited if after notice and demand for signature by the Department the taxpayer fails to provide a signature and 3 years have passed from the date the return was filed. An overpayment of tax refunded to a taxpayer whose return was filed electronically shall be considered an erroneous refund under Section 912 of this Act if, after proper notice and demand by the Department, the taxpayer fails to provide a required signature document. A notice and demand for signature in the case of a return reflecting an overpayment may be made by first class mail. This subsection (e) shall apply to all returns filed pursuant to the Illinois Income Tax Act since 1969.

(Source: P.A. 99-641, eff. 1-1-17.)