"Passive income" means two different things for an S corporation, and mixing them up is the most common mistake we see. One meaning is shareholder-level: whether your K-1 income is passive under the passive activity rules. The other is corporation-level: whether the S corp's own passive investment income triggers an entity-level tax or even ends the S election. Most owners with an operating business only need to worry about the first. Owners whose S corp has C corporation history and holds rentals, interest, or royalties need to watch the second.
Below, we separate the two regimes, show the math on the excess net passive income tax (often called the sting tax), and explain what to do if your S corp is near the threshold.
TL;DR
- Income from an S corp is generally passive to you only if you do not materially participate in the business. If you do, it is generally nonpassive. A K-1 alone does not make income passive.
- The corporate-level rules are separate. The IRS treats passive activity classification under §469 as independent of the passive investment income rules under §§1362(d)(3) and 1375.
- The excess net passive income tax requires accumulated C corporation earnings and profits at year-end plus passive investment income above 25% of gross receipts.
- Three straight years of both conditions terminate the S election. Prevention is far cheaper than relief.
- If your S corp was always an S corp, and has no C corporation earnings and profits, the entity-level tax does not apply.
Table of Contents
- Two meanings of passive: shareholder level versus corporate level
- When S corp income is passive to you
- What counts as passive investment income for the S corp
- The excess net passive income tax, also called the sting tax
- Three years above 25% can end the S election
- How to stay below the line
- Our perspective
- Work with us on your S corp structure
- FAQ
- Sources
Two meanings of passive: shareholder level versus corporate level
The two regimes answer different questions.
| Shareholder passive activity rules (§469) | S corp passive investment income rules (§§1362(d)(3), 1375) | |
|---|---|---|
| Who is tested | You, the shareholder | The S corporation |
| Question asked | Do you materially participate? | Is passive investment income more than 25% of gross receipts? |
| What is at stake | Whether losses and credits can offset other income | An entity-level tax and, after three years, the S election |
| Needs C corp history? | No | Yes, accumulated earnings and profits |
The IRS has expressly stated that the two regimes are independent. An activity can be passive for you under §469 and still not produce passive investment income for the corporation, and the reverse can also be true. Treat them as two separate checks.
When S corp income is passive to you
Per the IRS Schedule K-1 instructions for Form 1120-S, income from an S corporation trade or business is generally passive when you do not materially participate and generally nonpassive when you do. Rental activity and portfolio items such as interest and dividends have their own classifications. Receiving a K-1 does not by itself make anything passive.
In practice this plays out in a few common ways:
- You run the business full time. You almost certainly materially participate, so your share of ordinary business income is nonpassive.
- You are a silent co-owner. If you invest in an operating company and do not participate in a meaningful way, your share is generally passive.
- The S corp owns rentals. Rental income is treated under its own rules, and your participation level still matters for how losses are used.
- The S corp earns interest or dividends. The K-1 instructions list these as portfolio income, reported separately from ordinary business income.
Why classification matters
Passive classification mainly changes what your losses can do. Passive losses generally offset passive income, not wages or active business profit. The IRS K-1 instructions direct shareholders with passive activity losses or credits to Form 8582 or Form 8582-CR to determine limitations. If you hold rentals or investments alongside an operating business, our guide to the passive activity loss rules walks through the mechanics, and the self-rental rules cover the trap of renting property to your own business.
Also remember that you are taxed on your share whether or not the corporation distributes it. Treasury Regulation §1.1366-1 requires each shareholder to take into account a pro rata share of the corporation's items regardless of distributions. Your stock and debt basis then determines how much loss you can actually deduct.
What counts as passive investment income for the S corp
The corporate-level test is narrower and more technical. It looks at the corporation's gross receipts and asks how much came from passive investment income, generally rents, royalties, dividends, interest, and annuities, with exceptions. Details that matter:
- Stock and securities gains are excluded. For taxable years beginning after May 25, 2007, gains from sales or exchanges of stock or securities are included in gross receipts but not treated as passive investment income.
- Rents can be active. The IRS has ruled that rents may fall outside passive investment income when, on all the facts and circumstances, the corporation provides significant services or incurs substantial costs in the rental business. That ruling applied to one taxpayer and is not precedent, so it shows how the analysis works rather than a guarantee.
- Classification is fact-dependent. The same rental can be passive under §469 yet active for §1362(d)(3), because the tests differ.
If your S corp's income is mostly from an operating business, your passive investment income percentage is likely small. The risk grows when the operating business shrinks while an investment portfolio or rental holdings stay put, or when a company sells its operations and keeps earning interest on the proceeds.
The excess net passive income tax, also called the sting tax
The tax under IRC §1375 applies only when both of these are true at year-end:
- The S corporation has accumulated earnings and profits (E&P) from years when it was a C corporation.
- Its passive investment income is more than 25% of gross receipts.
If there is no C corporation E&P at year-end, Treasury Regulation §1.1375-1 says the tax does not apply even if passive investment income exceeds 25% of gross receipts. That is the key point for most owners: a company that has always been an S corp, or whose C corp E&P was fully distributed, is outside this tax.
When it does apply, the statute taxes the corporation's excess net passive income at the highest corporate rate under §11(b). The base is limited by the corporation's taxable income. The IRS notes that the corporation, not the shareholder, remains responsible for entity-level taxes such as the passive income tax.
How the calculation works
Excess net passive income is net passive income multiplied by a fraction. The numerator is passive investment income minus 25% of gross receipts. The denominator is passive investment income. Net passive income is passive investment income less the deductions directly connected to producing it.
Treasury's own example in §1.1375-1 uses $200,000 of gross receipts, $100,000 of passive investment income, and $10,000 of directly connected expenses:
| Step | Amount |
|---|---|
| Gross receipts | $200,000 |
| Passive investment income | $100,000 |
| 25% of gross receipts | $50,000 |
| Net passive income ($100,000 minus $10,000) | $90,000 |
| Excess over the threshold ($100,000 minus $50,000) | $50,000 |
| Excess net passive income ($90,000 × $50,000 ÷ $100,000) | $45,000 |
The tax is then computed on that $45,000, limited by taxable income. The same mechanics appear in a state manual example with $264,000 of gross receipts, $110,000 of passive investment income, and $32,000 of excess net passive income. That example applies a California rate, so use it for the arithmetic only, not the federal rate.
What it does to the K-1
The tax is not just an entity cost. When §1375 tax is imposed, each passive investment income item passed through to shareholders is reduced by a pro rata part of that tax, under IRC §1366(f)(3). Shareholders report a smaller amount, but the corporation has paid.
Three years above 25% can end the S election
The second consequence is more serious. If the corporation has accumulated C corporation E&P at year-end and more than 25% passive investment income in each of three consecutive years, the S election terminates on the first day of the next tax year after the third year.
The annual tax and the termination rule are separate. A corporation can owe the annual tax in a threshold year, while losing S status requires the E&P and threshold conditions for three consecutive years, as summarized in The Tax Adviser.
Relief exists in some cases. Under §1362(f), an inadvertent termination can be corrected if statutory conditions are met. In one IRS ruling, a termination was treated as inadvertent where corrective steps were taken within a reasonable period and the parties agreed to required adjustments. The Tax Adviser also reported a ruling in which the corporation agreed to distribute accumulated E&P through a deemed-dividend election. Private letter rulings are taxpayer-specific, so treat them as examples of relief, not an automatic cure.
There is also a waiver for the tax itself. IRC §1375(d) lets the Secretary waive it if the corporation reasonably establishes that it determined in good faith that it had no accumulated E&P and distributed the discovered E&P within a reasonable period.
How to stay below the line
The goal is to manage the three variables: C corp E&P, the passive investment income percentage, and the timing of the year-end test.
- Check for C corporation history. Did the company ever file as a C corporation, or merge with one? If the answer is no, you are generally outside §1375. Confirm it before you assume it.
- Calculate the percentage every year. Gather gross receipts and categorize interest, dividends, rents, and royalties before year-end, not after.
- Review rental structure. If rental activity involves significant services or substantial costs, document them. Classification depends on the facts, so the records matter.
- Consider distributing E&P. Removing accumulated E&P eliminates the condition that makes the tax apply. A deemed-dividend election is one route, and the right choice depends on your numbers.
- Hold investments outside the S corp where it makes sense. Separate entities for real estate or investments can keep an operating company's receipts clean, but structure decisions carry their own tax effects. Our S corp vs C corp guide covers the questions that decide entity choice.
- Keep the books clean. Shareholder loans, fringe benefits, and accountable plan reimbursements all affect reporting. See our notes on shareholder loans and accountable plans.
A quick self-check
| Your situation | Likely exposure |
|---|---|
| Operating business, always an S corp | Entity-level passive tax generally does not apply |
| Operating business with prior C corp years and small interest income | Review annually, risk is usually low |
| Prior C corp years, rentals or investments are most of the receipts | Higher risk, plan before year-end |
| Silent investor in an S corp | Passive treatment at your level, losses limited by §469 |
Our perspective
We see two kinds of owners with this question. The first read a headline about "passive income in an S corp" and worry about a tax that does not apply to them. The second have an old C corporation, a growing rental portfolio, and no one checking the percentage until the return is prepared.
Both are solved the same way: decide which regime you are asking about, then test it with real numbers. Shareholder-level passive classification drives how your losses are used. Corporate-level passive investment income drives entity tax and election risk. They need separate answers.
Our approach is year-round. We look at entity structure, rental activity, and income mix before year-end, when you still have choices, rather than after the books have closed. For multi-entity owners and real estate investors, that often means deciding where each income stream belongs so that your S corp stays clean and your losses stay usable.
Melissa
Work with us on your S corp structure
If your S corp has rentals, investment income, or C corporation history, we can map your exposure and plan the fix before year-end. Our Monthly Tax Advisory is $11,997 per year and our Quarterly Tax Strategy Sessions are $9,497 per year. For a focused starting point, the S-Corp Tax Strategy Accelerator is $997 one-off. Our Form 1120-S preparation is $1,800 one-off, and the full list is on our fee schedule.
If you are in Idaho or Oregon, you can also start with tax preparation in Boise.
FAQ
Can S corp income be passive?
Yes. Income from an S corp trade or business is generally passive to a shareholder who does not materially participate, and generally nonpassive when the shareholder does. Rental and portfolio items have their own classifications, and a K-1 alone does not make income passive.
What is the S corp sting tax?
It is the excess net passive income tax under IRC §1375. It applies to an S corp that has C corporation accumulated earnings and profits at year-end and passive investment income above 25% of gross receipts. It is imposed on the corporation, at the highest corporate rate.
Does the passive income tax apply if my S corp was never a C corp?
Generally no. Treasury Regulation §1.1375-1 says the tax does not apply when the S corporation has no C corporation earnings and profits at year-end, even if passive investment income exceeds 25% of gross receipts.
Do capital gains from stock count as passive investment income?
Not for taxable years beginning after May 25, 2007. Gains from sales or exchanges of stock or securities count in gross receipts but are not treated as passive investment income.
Can I lose my S election because of passive income?
Yes, if the corporation has accumulated C corporation E&P and more than 25% passive investment income for three consecutive years. Relief for an inadvertent termination may be available under §1362(f), so talk to a tax professional promptly.
Sources
- IRS Shareholder's Instructions for Schedule K-1 (Form 1120-S)
- IRS Private Letter Ruling 200044015
- IRS Private Letter Ruling 200946009
- IRS Private Letter Ruling 199906002
- IRS: S corporations
- California Franchise Tax Board S Corporation Manual, Chapter 7
- Treasury Regulation §1.1366-1 (GovInfo)
- 26 CFR §1.1375-1
- 26 U.S. Code §1375
- The Tax Adviser: Current developments in S corporations