S. 684 — Tax Administration Simplification Act

This section revises the deadline for a small business corporation to elect S corporation status under IRC §1362(b)(1) to the due date for filing the corporation's tax return for the taxable year (including extensions) from the 15th day of the third month of the taxable year. (Thus, for calendar-year taxpayers, the deadline extends from March 15 to September 15, assuming a six-month extension.) It further (1) permits such elections to be made on a timely filed return, (2) applies similar rules to qualified subchapter S subsidiary elections, (3) eliminates a prior timing restriction for qualified subchapter S trusts, and (4) authorizes the Secretary to treat certain late S corporation revocations as timely upon a reasonable cause determination. (S corporations provide pass-through tax treatment to eligible domestic corporations with 100 or fewer shareholders to avoid entity-level federal income tax.) The changes apply to elections for taxable years beginning after the calendar year of enactment and to revocations made after enactment.

This section revises the due dates for the second and third quarterly installments of estimated income tax payments by individuals to July 15 (from June 15) and October 15 (from September 15). The changes apply to installments due in taxable years beginning after enactment.

This section extends the mailbox rule—under which a document mailed by U.S. mail on or before its due date is deemed timely filed notwithstanding late receipt—to IRS-authorized electronic filings and payments. Specifically, for such documents or payments transmitted electronically on or before the due date but received (or, for payments, received and accounted for) after, the transmission date is deemed the filing or payment date; the Secretary of the Treasury must issue regulations within one year of enactment, with applicability to documents or payments sent on or after one year after enactment.