An S corporation is one that chooses to pass profits and losses through to the shareholders for Internal Revenue Service calculations. The S corporation files Form 1120S and Form 1120S Schedule K-1 for reporting to the IRS along with quarterly estimated taxes. The filer can file an amended Form 1120S return or amended Schedule K-1 forms for the IRS.

Amended Form 1120S

An S corporation has no more than 100 shareholders and one class of stock; shareholders must be individuals, trusts or estates. The S corporation must be a domestic corporation that is not involved in financial institutions, international sales or insurance. The corporation must have an IRS Form 2553 on file for election to be an S corporation. Form 1120S is the U.S. Income Tax Return for an S Corporation. Use the same form as you used to file the original S corporation tax return, making certain that you have the correct year. Complete the basic information for the year covered and check box H(4) for an amended return. The IRS requests that you attach a schedule of changes line by line, with an explanation of the changes. Complete the form as well; instructions warn against referring to attachments.

Amended Schedule K-1

Schedule K-1 is the Shareholder’s Share of Income, Deductions, Credits etc. and Part II identifies the specific shareholder. Start with the Schedule K-1 form for the appropriate year and check the “Amended K-1” box at the top of the form. Each Schedule K-1 has some variable information, including the codes used. Use the Schedule K-1 instructions to locate the necessary codes for the completion of the amended Schedule K-1. Attach all necessary amended Schedule K-1 forms to the Form 1120S. Send a copy of any amended Schedule K-1 form to the shareholder as well as to the IRS.

State Income Tax

Amending the federal income tax return may affect shareholders and state income tax returns. Contact your Department of Revenue or taxing agency to locate the correct forms for amending your state tax return. When you provide an amended Sch. K-1 to your shareholder, notify him of the potential need for completion of an amended state tax return as well.

Filing Amended 1120S or K-1

Refer to the IRS instructions for Form 1120S to locate the correct mailing address for the completed amended forms for the S corporation. The address depends on the total corporate assets at the end of the tax year and the state where the principal business office is located. The IRS splits these S corporation returns between Cincinnati, Ohio and the Ogden, Utah office.