S-Corporation Tax Compliance
An S-corporation files Form 1120-S and issues a Schedule K-1 to each shareholder, who reports that income on their personal return. The election can lower self-employment tax, but only if the owner is paid reasonable compensation as W-2 wages first. Blue Sage handles the return, the payroll, the basis tracking, and any state that does not follow the federal election.
What's included
- Form 1120-S preparation and e-filing, federal and state
- Schedule K-1 for every shareholder, with the personal return coordinated
- Reasonable compensation analysis, documented in writing
- Payroll setup and quarterly filings, or review of your existing provider
- Shareholder basis schedules, maintained year over year
- Accountable plan for home office, mileage, and owner reimbursements
- Multi-state and New York City filings where nexus exists
- Late S-election relief under Rev. Proc. 2013-30 where you qualify
Who this is for
Owner-operated businesses that already run as an S-corporation, LLCs that have elected S treatment, and business owners whose profit has grown to the point where the election is worth modeling — generally once net profit is consistently above roughly $40,000 to $60,000 a year.
It is also for owners who made the election themselves, or had it made for them, and were never told what came with it. If nobody has run a compensation study, your basis has never been tracked, or you have been taking distributions without payroll, that is the situation this page is written for. It is fixable, and the fix is cheaper than the notice.
Deadlines and rules worth knowing
| Item | What applies |
|---|---|
| Return filed | Form 1120-S, plus a Schedule K-1 to every shareholder |
| Federal due date | 15th day of the 3rd month after year end — March 15 for calendar-year filers |
| Extension | Form 7004 extends the return six months, to September 15. It does not extend the shareholders' personal payment deadline. |
| Late-filing penalty | Charged per shareholder, per month or part month, up to 12 months. Two owners means it accrues twice as fast. |
| Election deadline | Form 2553, filed within 2 months and 15 days of the start of the tax year the election takes effect |
| Missed the election | Late relief is often available under Rev. Proc. 2013-30 if you have otherwise been operating as an S-corporation |
| Shareholder limits | 100 shareholders maximum, U.S. individuals and certain trusts and estates only, one class of stock |
| New York City | Does not recognise the federal S election. NYC taxes the entity under the general corporation tax regardless. |
What counts as reasonable compensation
Reasonable compensation is the salary an S-corporation must pay a shareholder who works in the business, before any profit is taken as a distribution. The IRS expects it to reflect what the same work would cost on the open market — judged on role, hours, experience, and how much of the revenue the owner personally generates.
There is no percentage in the tax code, and the rules of thumb passed around online are not a defence. What holds up is a documented study: comparable wage data for the role and region, the owner's actual hours and duties, and a written conclusion kept with the file. That is what we produce, and it is what gets shown if the return is ever questioned.
How we work
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Review what exists
We read last year’s return and whatever records you have. Most of what needs fixing is visible quickly.
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Fixed quote in writing
Scope and price before anything starts, counting entities, states, and any cleanup needed.
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File and maintain
Returns prepared and filed, notices answered, and a projection before year end.
Questions
What is reasonable compensation for an S-corporation owner?
Reasonable compensation is the salary an S-corporation must pay a shareholder who works in the business, before any profit is taken as a distribution. The IRS expects it to reflect what the same work would cost on the open market, based on role, hours, experience, and the revenue the owner personally generates. Setting it too low is one of the most common triggers for examination.
When is the S-corporation tax return due?
Form 1120-S is due on the 15th day of the third month after the end of the tax year, which is March 15 for a calendar-year S-corporation. Filing Form 7004 extends the deadline six months to September 15. The extension covers the return only, not any tax the shareholders owe personally.
What is the penalty for filing an S-corporation return late?
The late-filing penalty is charged per shareholder, per month or part of a month the return is late, for up to twelve months. The rate is set by statute and indexed annually. Because it multiplies by the number of shareholders, a two-owner S-corporation accrues it twice as fast. First-time abatement or reasonable cause relief can often remove it.
Can an S-corporation file in more than one state?
Yes, and it frequently must. An S-corporation files where it has nexus, which can arise from an office, employees, property, or economic activity in a state. Some states do not recognise the federal S election and tax the entity directly. New York City, for example, taxes S-corporations under the general corporation tax regardless of the federal election.
What is shareholder basis and why does it matter?
Basis is your investment in the S-corporation for tax purposes, adjusted each year for income, losses, contributions, and distributions. It sets the limit on losses you can deduct and determines whether a distribution is tax-free. Basis must be tracked continuously, because reconstructing it years later after it has gone unrecorded is expensive and often incomplete.
Last reviewed 11 September 2026 by Fahadun Nabi, Founder, Blue Sage Tax and Accounting Inc.. General information, not advice for your specific situation.
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