No. Do not file Form 1120S prior to proper filing of S Corporation election unless applying for relief for a late S Corporation election under Revenue Procedure 2003-43, or Revenue Procedure 2004-48, do not file Form 1120S, U.S. Income Tax for an S Corporation, for any tax year before the year the election takes effect.

If the corporation is required to file Form 1120, U.S. Corporation Income Tax Return, or any other applicable tax return, continue filing until the election takes effect. When an election has been accepted the IRS will send a CP 261, Notice of Acceptance As An S Corporation.