Where to File an S Corp Tax Return: Federal & State Info

An S corporation tax return, specifically Form 1120-S, serves as an informational document for the Internal Revenue Service (IRS). This form details the income, deductions, gains, losses, and credits of a domestic corporation that has elected S corporation status. Unlike C corporations, S corporations are considered “pass-through” entities, meaning the business itself generally does not pay federal income tax. Instead, the profits and losses are passed through to the shareholders’ personal income tax returns, where they are taxed at individual rates, thus avoiding double taxation. The primary purpose of Form 1120-S is to report these financial activities and to provide shareholders with their share of the business’s profits and losses via Schedule K-1.

Federal S Corporation Tax Return Filing

S corporations have two methods for filing their federal tax return, Form 1120-S: electronic filing (e-filing) and mailing a paper return. Electronic filing is often mandatory for many S corporations.

For returns required to be filed on or after January 1, 2024, S corporations must e-file Form 1120-S if they are required to file 10 or more returns of any type during the calendar year. This threshold includes return types such as income tax, employment tax, excise tax, and information returns, expanding the number of corporations subject to mandatory e-filing. Even if an S corporation does not meet this mandatory e-filing threshold, electronic filing is still encouraged.

The e-filing process involves using IRS-approved tax preparation software or engaging an authorized e-file provider. This software facilitates the accurate completion and secure transmission of Form 1120-S, along with all related forms, schedules, statements, and attachments, directly to the IRS. E-filing also applies to extensions, such as Form 7004 for an automatic six-month extension. The system provides immediate confirmation of successful transmission.

For S corporations not required or unable to e-file, mailing a paper copy of Form 1120-S to the IRS is an alternative. The specific mailing address depends on the S corporation’s principal business address, total assets, or whether Schedule M-3 is filed. S corporations with a principal business in states like Connecticut, Delaware, Illinois, or New York, and total assets less than $10 million (and not filing Schedule M-3), mail their returns to the Department of the Treasury, Internal Revenue Service, Kansas City, MO 64999-0013.

S corporations located in states such as Alabama, Alaska, California, Florida, or Texas, regardless of asset size, send their returns to the Department of the Treasury, Internal Revenue Service, Ogden, UT 84201-0013. If an S corporation’s principal business is in a foreign country or U.S. possession, the return is mailed to Internal Revenue Service, P.O. Box 409101, Ogden, UT 84409. Consult the latest instructions for Form 1120-S on the IRS website for current mailing addresses, as these can change.

When mailing a paper return, ensure the form is properly signed and dated by an authorized officer of the corporation. All required schedules and forms, such as Schedule K-1 for each shareholder, must be attached. Using certified mail with a return receipt provides proof of mailing and delivery for record-keeping or IRS inquiries. Private delivery services designated by the IRS can also be used, but specific street addresses apply for these services, as they cannot deliver to P.O. boxes.

State S Corporation Tax Return Filing

In addition to federal requirements, S corporations often face separate income tax return filing obligations at the state level. Most states require an S corporation income tax return if the entity has established “nexus” within that state, meaning it has a sufficient connection, such as conducting business operations or having a physical presence. These state-level filings are distinct from the federal Form 1120-S.

The requirements for state S corporation tax returns vary from one state to another. Some states may fully recognize the federal S corporation election and align their tax treatment with federal guidelines. Other states might not entirely recognize the federal S corporation election, potentially taxing the entity as a C corporation, or imposing specific state-level taxes like franchise taxes or minimum taxes, even if no income is generated. For example, some states impose an annual minimum franchise tax on S corporations, such as California’s $800 minimum tax.

State filing requirements include various forms and submission methods, such as electronic filing, mailing, or a combination. Some states may require S corporations to file composite returns on behalf of their nonresident shareholders, simplifying the filing burden for those individuals. The specific forms, due dates, and payment methods are unique to each state’s tax laws.

To find state filing information, S corporations should consult the official website of the state’s tax authority. This agency is often called the Department of Revenue, Franchise Tax Board, or a similar designation. Searching for terms like “S corporation tax [State Name]” or “Form 1120-S [State Name]” on these official state government websites lead to the relevant forms, instructions, and filing addresses. These resources provide detailed guidance on state-specific nexus rules, tax calculations, and submission procedures, ensuring compliance with local tax laws.