A client came to us last year with a simple marketing agency, clean business model, and zero employees in the United States. They’d been paying U.S. Taxes they never owed. Not a small amount. Enough to make your stomach turn.
The worst part is that the rules that could have saved them are not opaque. They’re just not talked about in ways that make sense to someone who didn’t grow up filing a 1040.
If you’re a foreign entrepreneur looking to set up or grow your business in the U.S., there are five tax rules that will shape how you recognize your revenue and take income. Get them right, and you unlock advantages that U.S. Citizens genuinely cannot access. But get them wrong, and you’re handing money to a government that never asked for it.
Here’s how to do it (more below the video):
Rule #1: Understand Effectively Connected Income (ECI) Before You Do Anything Else
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Now, let’s dive into Effectively Connected Income, or ECI. It’s the big one. ECI decides if your business income creates U.S. Tax obligations. Here’s the gist: if your income is “sourced” in the U.S., which means it’s tied to activities on American soil, then you’ve got ECI. Having ECI means you owe U.S. Tax, you need to file a 1040-NR (or a business return if you run an entity), and you follow American tax rules. But here’s the catch. If no one in your company lives in the U.S., and you provide your services completely outside the U.S., you might have zero ECI. That translates to zero U.S. Tax on that income. (Yep, you read that right.)
How This Works in Practice
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Point being, let’s say you’re running a marketing agency from Argentina. You set up a U.S. LLC, open U.S. Bank account for that business, and start providing marketing services to clients wherever they are. American clients, Argentinian clients, clients in Germany. All income flows into that U.S. LLC. And you don’t pay U.S. Tax on it. Why? Because you performed the work outside United States. No ECI. This is one of most powerful advantages available to foreign entrepreneurs. Period.
What Triggers ECI (And Ruins Everything)
Now the tricky part. You have to be careful not to accidentally create ECI. Here’s what commonly trips people up:
- Physical presence for business activities. Flying to the U.S. To meet clients in person, pitching in a conference room in New York, shaking hands in Miami. That’s performing services on U.S. Soil, and that triggers ECI.
- Owning or leasing physical space. Buying a warehouse, renting an office. These create a direct connection to U.S. Business activity.
- Storing inventory. If you’re in e-commerce and you store enough inventory at certain U.S. Distribution centers, some states may consider that a trigger.
- Real estate. Owning property in the U.S. Is a direct ECI trigger, and it brings its own set of rules we’ll cover later.
Pro tip: Keep your client interactions on Zoom. Keep your work outside U.S. Borders. And if you’re running an e-commerce operation, talk to a tax advisor before choosing where to warehouse your products.
Every situation has nuances worth examining. But the takeaway is clear: if you structure things correctly, you can operate a U.S. Business entity without owing U.S. Income tax. That’s not a loophole. That’s the law working as designed.
Rule #2: The 183-Day Big Presence Test Will Make or Break Your Tax Status
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You could trigger big tax obligations in the U.S. Even without ECI. This happens due to the 183-Day Substantial Presence Test. It has two parts, and both are important.
The Two Thresholds
- You must be present in U.S. For at least 31 days during the calendar year.
- You must accumulate 183 days or more over three-year weighted calculation.
People often get confused by that second part. It’s not just about being in the U.S. For 183 days in one year. The formula looks back over three years with a weighted count.
The Weighted Formula
Here’s how it actually works:
From what I’ve seen, – Current year: Count 100% of your days in the U.S. – Previous year: Count one-third of your days. – Year before that: Count one-sixth of your days.
Add those three numbers. If you hit 183 or more, you’ve triggered big presence. Congrats, you are now a U.S. Tax resident.
A Quick Example
Let’s say you spent 100 days in U.S. For three straight years. The math is simple:
- Current year: 100 days (100% = 100)
- Prior year: 100 days (1/3 = 33)
- Year before: 100 days (1/6 = 17)
- Total: 150 days
That’s less than 183. You’re safe. You didn’t trigger substantial presence.
The Simple Rule of Thumb
What’s the most straightforward way to stay clear? Just spend 120 days or fewer in the U.S. each year (around four months), and you won’t trigger test. That’s the safe limit. If you’re getting close to four months in U.S. for consecutive years, think about cutting back next year. The weighted formula means those days keep counting long after you leave.
Visa Exceptions
Does this sound familiar?
Certain visa types can exempt you from the substantial presence test. Student visas and certain teaching visas (like Q visas) often qualify. Confirm to check yours before assuming. A quick chat with an advisor can save you from a big financial headache later on.
Rule #3: Know What FDAP Income Is and How It’s Taxed
The Third Rule: FDAP Income
Most foreign entrepreneurs have never heard of this one. It’s called FDAP. Fixed, Determinable, Annual, or Periodical income.
FDAP is a category of income that gets taxed differently than regular business income. And the problem is, lot of foreign entrepreneurs are earning it without realizing it. FDAP typically covers passive types of income like:
- Dividends
- Interest
- Royalties
- Rents (in certain situations)
- Other periodic payments
With ECI, the whole question is whether your income is connected to U.S. Business activity. FDAP works differently. If you’re receiving FDAP income from U.S. Sources, you’re generally subject to a flat withholding tax no matter where you live or where you do your work.
A lot of time, you don’t even see it coming – the entity paying you withholds the tax and sends it straight to the IRS before the money ever hits your account.
Pro tip: Tax treaties between the U.S. and your home country may actually reduce or eliminate FDAP withholding rates. Don’t just assume the default rate applies to you. Look into the treaty provisions for your specific country, or honestly, find someone who knows treaty benefits and have them review your situation.
Many foreign entrepreneurs I have worked with focused on ECI which was smart, but they completely ignore FDAP. If you’re earning any passive income from U.S. Sources, investment returns, licensing fees, royalties, any of that, you need to understand how FDAP applies to your situation.
Rule #4: FIRPTA Can Catch You Off Guard With Real Estate
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If you’re thinking of investing in U.S. Real estate, just know that you need to be aware of FIRPTA, the Foreign Investment in Real Property Tax Act.
FIRPTA is here for a single reason: to see to it foreign investors pay taxes when they sell U.S. Property, and the way it works surprises a lot of entrepreneurs.
How FIRPTA Works
When a foreign individual sells U.S. Real estate, the buyer usually has to withhold a portion of the gross sales price and send it to IRS. This isn’t a tax on profit. It’s a withholding based on the whole sale amount, taken upfront. You can file a return later to settle the actual tax owed vs. What’s been withheld, but that first cash hit can be pretty clear. This rule applies whether it’s a commercial building, a residential rental, or just vacant land. Real estate creates Effectively Connected Income (ECI), and FIRPTA slaps on another layer of withholding.
Why This Matters for Your Planning
FIRPTA changes your exit strategy and more importantly, it often reshapes how you structure your investment from day one. The type of entity you’re using, how you hold the title, your country of origin, all of it affects your FIRPTA exposure. Tons of foreign investors buy U.S. Properties through an LLC, not fully grasping tax consequences later on. One catch. They sell and suddenly find a huge chunk of their profits snagged by the IRS, trapped in a waiting game for months just to get a refund. That something you’re up for? Probably not.
Pro tip: If real estate’s in your U.S. Strategy, fix the structure early on. Restructuring later can cost you big and sometimes isn’t even an option. This isn’t DIY project.
Rule #5: Estate Tax Exposure Is Bigger Than You Think
Here’s the rule almost nobody talks about until it’s too late – foreign nationals with U.S.-based assets may be subject to U.S. Estate tax, and exemption threshold is dramatically lower than what U.S. Citizens receive.
U.S. Citizens and residents enjoy a large estate tax exemption. But for foreign nationals, the exemption is a fraction of that amount. Which means if you hold meaningful U.S. Assets (real estate, business interests, certain investments), your estate could face a serious tax bill. This is not hypothetical, it’s a structural risk that grows with every dollar of U.S. There’s a catch though, it on assets you accumulate.
What Counts as U.S. Asset?
For estate tax purposes, US-sited assets generally include:
- Real property located in the U.S.
- Tangible personal property in the U.S.
- Shares of U.S. Corporations (in many cases)
- Certain business interests
The part that stings a lot of people is that even if you structured your business perfectly to avoid income tax through ECI rules, your ownership interest in U.S. assets can still expose your estate to tax.
What You Can Do About It
Estate tax planning for foreign nationals is complex, but there are legitimate strategies to reduce exposure. The right entity structure, the right holding jurisdiction, and proper planning can make a massive difference. But you have to think about it before you build your U.S. Portfolio, not after (so call us before you start, not before your exit).
This is one of those areas where the cost of getting professional advice is trivial compared to the cost of getting it wrong.
Putting It All Together
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These five rules aren’t just jargon, they’re key to smart choices for every foreign entrepreneur in the U.S. market.
Here’s a quick reference guide:
- ECI (Effectively Connected Income): If you do your work outside the U.S. and have no U.S. presence, you might pay zero U.S. income tax on your earnings. Plan accordingly.
- The 183-Day Major Presence Test: Stay under 120 days per year in the U.S. to avoid U.S. tax residency through physical presence.
- FDAP Income: Passive income from U.S. sources (like dividends, royalties, interest) comes with withholding tax. Check your country’s tax treaty for lower rates.
- FIRPTA: Selling U.S. real estate as a foreign investor mandates withholding on the gross sale price. Get your ownership structure right from the start.
- Estate Tax: Foreign nationals have a lower estate tax exemption on U.S. assets. Plan your asset structure early.
Foreign entrepreneurs can access some pretty good tax positions in the U.S. (ones U.S. Citizens can’t). But only if you know the rules and get your setup right from day one. Every situation is unique, and what’s good for a marketing agency in Argentina might not fit a real estate investor in Singapore. The details matter here and you need to work with someone who understands the details.
If you’re thinking about starting or expanding a U.S. Business, set up a free discovery call with BizBud. We work with foreign entrepreneurs daily and want to hear about your situation.
About The Author:
Cameron Botes is the founder of BizBud, a tax and accounting firm built for content creators, influencers, digital nomads, and entrepreneurs building businesses across borders. A former professional soccer player across four continents, Cameron brings the same discipline, preparation, and pressure-tested execution from his athletic career into helping business owners plan ahead, stay compliant, and keep more control over their financial future.
Since founding BizBud in 2020, Cameron has grown the firm from a one-person practice into a team of CPAs and tax advisors serving hundreds of clients across the U.S. and around the world. With an MBA in finance and accounting, international business experience, and a team with backgrounds at firms like PwC, Deloitte, and EY, Cameron helps creators and founders simplify taxes, clean up their books, and build smarter systems so they can focus on the work they actually love.
