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Form 1120S


Form 1120S is a tax document used by S corporations in the United States to report their income, losses, dividends, and other tax-related information to the Internal Revenue Service (IRS). Specifically, this form records the financial activity of the business for the year and determines the flow-through of income and losses to its shareholders. It’s an essential requirement for S corporations as it aids in confirming compliance with tax obligations.


The phonetics of the keyword “Form 1120S” is /fɔːrm waʊn waʊn tuː ‘oʊ ‘ɛs/.

Key Takeaways

  1. Specific Filers: Form 1120S is to be filed by S Corporations, entities that elect to pass corporate income, losses, deductions, and credits through to their shareholders for federal tax purposes. This means, the shareholders of the S corporation report the flow-through of income and losses on their personal tax returns and are assessed tax at their individual income tax rates, allowing S corporations to avoid double taxation on the corporate income.
  2. Required Information: In Form 1120S, S Corporations are required to report their annual income and expenses, balance sheet information, shareholders details, specific transactions with shareholders, ownership changes, corporate distributions, passive income and taxes paid (if any), to the IRS.
  3. Deductions and Loss Limitations: Form 1120S helps corporations calculate their net income or loss for federal tax purposes, which is then passed through to shareholders. However, the deductions and losses that can be claimed by shareholders are limited to the basis of their stock in the S corporation, along with any debt the corporation owes to them.


Form 1120S is crucial in the world of business and finance as it is the U.S. Income Tax Return for an S Corporation. This form serves as an official document filed annually by S corporations to the Internal Revenue Service (IRS). Its importance lies in its ability to report the corporation’s income, deductions, credits, and other information, which helps determine the overall corporate tax liability. It also reports each shareholder’s pro-rata shares of income, deductions, credits, etc. Hence, Form 1120S plays an essential role in maintaining transparency and ensuring compliance with tax laws by S corporations.


Form 1120S is instrumental in the operations of small-sized and medium-sized corporations in the United States, mainly for tax purposes. The purpose of this form is to report the income, losses, deductions, and credits of a domestic corporation or other entity for any tax year covered by an election to be an S corporation. Essentially, the use of this form allows the Internal Revenue Service (IRS) to assess the financial activities of S-corporations and subsequently determine their federal tax liability.The proper filing of Form 1120S prevents the double taxation that typically plagues regular corporations. In other words, while most corporations pay taxes at both the corporate level and again at the individual shareholder level when dividends are distributed, S corporations’ net income, losses, deductions, and credits generally flow through to the shareholders, who then report them on their individual tax returns. Therefore, Form 1120S is thoughtful of smaller businesses as it provides a way for the shareholders to pay taxes on their portion of the business’s profits directly on their individual tax returns.


Form 1120S is a tax document used by S corporations to report their income, gains, losses, deductions, credits, etc. to the IRS. Here are three real-world examples:1. Small Business Operations: A family-run restaurant that is organized as an S corporation would utilize Form 1120S. The form would detail the restaurant’s earnings, deductions such as payroll and operating expenses, and any credits applicable to the business. It provides the IRS with a clear understanding of the company’s net earnings and tax liability.2. Tech Startups: A tech startup in Silicon Valley classified as an S corporation would also use Form 1120S. If the startup has received venture capital or other forms of income during the taxable year, it would report this on the form. Additionally, any R&D tax credits or software development costs could be reported on this form.3. Real Estate Investment Companies: A small real estate investment company operating under an S corporation structure would file Form 1120S. If the company purchased or sold any properties throughout the year, these transactions would be reported on the form, as well as any rental income and related expenses. Any real estate tax credits would also be reflected on this form.

Frequently Asked Questions(FAQ)

What is Form 1120S?

Form 1120S is a tax document used by S corporations to report their income, gains, losses, deductions, credits, and to calculate their federal income tax liability.

Who needs to file Form 1120S?

S corporations – corporations that have elected to pass corporate income, losses, deductions, and credits through to their shareholders for federal tax purposes.

When is Form 1120S due?

Form 1120S is due on the 15th day of the third month after the end of the corporation’s tax year. For corporations on a calendar year, the deadline is March 15.

What information is needed to complete Form 1120S?

General information about the corporation, income, deductions, tax and payments, Schedule K, Schedule K-1, and other schedules as needed depending on the corporation’s circumstances.

What is Schedule K in Form 1120S?

Schedule K is a section in Form 1120S where the corporation reports the shareholders’ shares of the corporation’s income, credits, deductions, etc.

What is Schedule K-1 in Form 1120S?

Schedule K-1 is a document prepared for each shareholder, reporting the shareholder’s pro-rata share of the S corporation’s income, credits, deductions, etc.

Can Form 1120S be filed electronically?

Yes, Form 1120S can be filed electronically through an IRS Authorized e-file Provider or by using IRS e-file software.

How can I amend a Form 1120S that has already been filed?

To amend a filed Form 1120S, a corporation should file a new Form 1120S, complete the entire form, and check the Amended Return box.

What penalty may I face if I file Form 1120S late?

There may be a late filing penalty of 5% of the unpaid tax for each month or part of a month the return is late, up to a maximum of 25% of the unpaid tax.

Do state tax requirements also apply when filing Form 1120S?

Yes, many states have requirements for S corporations that are similar to the federal Form 1120S, but it’s always beneficial to check with your specific state’s tax agency.

Related Finance Terms

  • Subchapter S Corporation
  • Shareholder’s Share of Income
  • IRS
  • Business Tax Return
  • Earnings and Profits

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