Corporation Tax Return (Form 1120)
We review your documents and quote you a fixed fee for the return.
LLC and LP Tax Return (Form 1065)
We review your documents and quote you a fixed fee for the return.
Zero Tax Return for LLCs (Form 5472 with Form 1120)
Apply for an EIN with the IRS
Payroll for Non-Resident Companies in the US
Plus $60 per employee per month.
IRS Letters & Penalties
Requests for abatement of an IRS penalty, for example on Form 5472, at a fixed fee per letter.
View service →
Withholding Tax
W-8 forms and US withholding tax on payments to your company.
View service →Behind all the services above is the same engagement: we run the American side of your books. For US companies just as much as for European businesses that have become taxable in the US. In English, with a dedicated contact, for a fee that is fixed before you engage us.
The trigger is almost always the same: there are obligations in the US, and nobody is clearly responsible for them. Your accountant at home handles your national law. An American accountant knows US law but rarely cares what it means back in your home country. That gap is exactly where we work.
What ongoing support covers
The scope of services is the same in both cases:
Your company has no business in the US, no permanent establishment and no employees there? Then our sister firm zerotax.llc looks after it.
Who we work for
Your own US company
One case is your own US company. A corporation files a tax return every year from the year it is formed, even with no revenue. A foreign-owned single-member LLC files in every year with reportable transactions, and those already include formation costs and the owner's contributions and distributions. So a dormant company is rarely a company with nothing to file, and that is exactly what people are rarely told when they set one up.
The foreign business with US ties
The other case is the foreign business with US ties. Tax obligations arise there from, among other things:
- a stake in a US company or in a partnership or LLC
- passive US income such as royalties, rent or interest
- the sale of goods in the US or inventory held there
- a branch or permanent establishment, even a short-lived one
- proceeds from the sale of US assets, especially real estate
- employees working for you in the US
That last point catches people out most often. A single person working for you from home in Texas triggers reporting and withholding obligations long before anyone has thought about opening an office. How the taxation behind it works in detail is covered in our guides on taxation of business profits and taxation of your US corporation. If you haven't settled on an entity type yet, the entity comparison will help.
If you haven't filed in years
This is the most common reason businesses contact us, and there's no need to apologize for it. Companies set up years ago through a provider that sold the formation and then disappeared are, in our experience, the rule, not the exception.
We work through these cases step by step: first an inventory of which years are open and which forms are missing, then the catch-up filings, then, where the conditions are met, a request for penalty abatement. It's urgent because the harshest US penalties aren't tied to underpaying but to a missed filing:
What happens over the year
With our ongoing support, you don't have to keep track of the calendar. A typical engagement runs like this:
We reach out to you ahead of each of these deadlines. That's the practical difference from an arrangement where you have to remember that you should hire someone.
What we need from you
Getting started is easier than most people expect. To onboard you, we need:
That last item is the most important, and also the one most often kept too brief. It determines which returns are due at all and which states you need to be registered in. If you're not sure what's relevant, err on the side of too much detail; sorting it out is our job.
How we work with your accountant at home
We don't replace your current advisor, we complement them. In practice, that means we take over the US side completely and reconcile the figures with your accountant before anything is filed on either side.
It sounds obvious, and it isn't. Double tax treaties don't stop you from having a filing obligation in both countries; they decide which country may tax and how the other one offsets the burden, usually through a credit. For that to work, both returns have to be filed and the numbers have to match. That is exactly where things fall apart when two advisors in two countries work without talking to each other.
Why an internationally focused firm
Since 2008, Mount Bonnell Advisors has worked exclusively with internationally active clients, many of them from Europe. We coordinate with your accountant at home and our US colleagues on who files which return and when, so that in the end nobody is left waiting on anyone else.
For you, the practical effect is simple: you explain your situation once, in English, and don't have to translate it into two legal systems at the same time. That is the real difference from a purely American provider.
Switching from another provider
Switching in the middle of the fiscal year is no problem, and we see it often. We need neither consent nor a handover from your current provider: the records belong to you, and your tax ID stays the same.
It only takes more work where the previous provider is also listed as the company's Registered Agent or address. In that case we also have to notify the state, so that mail arrives where someone actually reads it. We handle that too. It's a formality, not an obstacle.
If you can no longer get to your login details or your bookkeeping because a provider has stopped responding, tell us when you first get in touch. We'll then rebuild the records from your account transactions and the registry data. It takes a little longer, but it has never failed yet.
How engaging us works
If you'd like to work with us, order the service directly on its page or go through the engagement page. The order form asks for the details we need to get started.
We then set up your file, check which years are still open and get back to you with a list of the documents we need. You get one dedicated contact who knows your case, not a rotating team. If you are also personally taxable in the US, for example as a shareholder or green card holder, that runs through our tax services for individuals and is handled under the same roof.
For recurring work we charge flat fees, so you know what the year will cost before you engage us.
For matters whose scope can't be estimated reliably in advance, such as several open years or a permanent establishment question, we start with a scoping review: we go through the case and tell you the effort involved, and the fee for this review is credited toward the engagement that follows. If you don't engage us, it is not refunded.
Current rates are listed in our fee overview.