The tax reality that still surprises European companies entering the US

Delaware, with fewer than 1.1 million residents, hosts more than 1.8 million registered business entities. More companies than people. European executives looking seriously at US market entry tend to hit that statistic and ask whether Delaware incorporation is the obvious default. A few weeks in, they hit a second realization: the US tax and compliance landscape is more fragmented than anything they have worked with at home.

This gap is structural. A French SaaS company that spent a decade operating under a single corporate tax regime, one VAT system, and a broadly homogeneous EU payroll structure discovers a different universe when its first US customer signs in Texas, its sales rep lives in California, and its newly-hired engineer is based in New York. Each of those jurisdictions carries its own rules. None of them talk to each other. The assumptions that worked across the EU do not port over.

The surprises cluster in four predictable places.

A tax system built in three layers

The structural point is the biggest. Tax in the US runs as three layers stacked on top of each other, and the overlap can be substantial.

Federal tax behaves roughly as Europeans would expect. Corporate income tax sits at a flat 21% after the 2017 Tax Cuts and Jobs Act. Payroll tax is collected by the IRS. Federal forms are filed once a year for corporate income, quarterly for payroll and estimated taxes. This layer is familiar in shape if not in form.

State tax is where the model departs from European intuition. Each of the fifty states sets its own corporate rate, its own individual rate, its own rules on what counts as a deductible expense, its own standards for what constitutes nexus. California’s top corporate rate is 8.84%. Texas has no corporate income tax but levies a franchise tax. Delaware charges no corporate income tax on companies that do not operate within its borders, which is the genuine reason for its popularity as a registration state. Wyoming, Nevada, and South Dakota skip individual state income tax entirely.

None of this is harmonized. A European company billing customers across ten states can easily find itself filing returns in ten jurisdictions under ten sets of rules.

Local tax is the third layer. Cities and counties in many states levy their own income, gross receipts, or business license taxes. New York City adds a corporate tax on top of New York State. Philadelphia has a Business Income and Receipts Tax. San Francisco runs its own payroll and gross receipts tax. For companies operating in major urban US markets, the local layer alone can add two to four percentage points to the effective tax rate without appearing anywhere in the corporate headline number.

A US effective tax rate is the sum of three numbers: federal, state, and local. The composition shifts depending on where revenue is booked and where employees sit. A European CFO who reports “we pay 25% corporate tax in the US” to the board is usually reporting only the federal headline and ignoring the other two layers.

The illusion of the equivalent entity

European legal structures do not map cleanly onto American ones. That technical-sounding sentence hides one of the costliest misunderstandings in transatlantic expansion.

Consider a mid-sized German GmbH that decides to establish a US subsidiary. The instinctive move is to set up a US corporation, typically an Inc. or LLC, and treat it as the American analog of the GmbH. The next step depends on a choice most founders do not realize they are making: the tax election. An LLC can be taxed as a C-Corporation, an S-Corporation, a partnership, or a disregarded entity. Each option carries radically different consequences for how US profits are taxed, how distributions flow back to Germany, and how the IRS views the parent-subsidiary relationship.

Take the case of a European founder who flies into Arizona to launch a US operation. A local attorney forms the LLC. A local bookkeeper handles monthly filings. Things run smoothly until the first meaningful tax question arises, at which point the founder discovers that the bookkeeper does not handle entity-level strategy, and the attorney does not handle ongoing tax planning. Engaging one of Arizona’s leading CPA and tax advisory firms, such as K&R Strategic Partners in Mesa, is the step that converts a US entity from a running liability into a functioning, tax-efficient arm of the European business.

The election question is just the start. Once an entity is formed, the question becomes how profits move. Dividends from a US C-Corp to a European parent are subject to US withholding tax. The default rate is 30%, reduced only where an applicable tax treaty applies. Most EU member states have treaties with the US that bring the rate down to 5% or 15%, depending on ownership percentage and specific conditions. Missing the treaty documentation, or failing to file the correct withholding forms (W-8BEN-E being the most common), leaves 25 to 30 cents on every dollar of dividends on the table permanently. Some of it is recoverable through a refund process. The process takes months and requires a level of documentation most companies have not been maintaining.

Transfer pricing is the related trap. Any time the European parent sells goods, provides services, licenses intellectual property, or handles management support for the US subsidiary, the pricing of those transactions is scrutinized by both the IRS and the parent’s tax authority. The instinct to set intra-group prices in whatever way minimizes the overall group tax bill is exactly the behaviour that triggers audits on both sides of the Atlantic.

There is one more structural choice. Operating through a US subsidiary is one option. Operating as a US branch of the European entity is the other. The branch is legally simpler and cheaper to set up, but it carries a 30% branch profits tax on earnings treated as effectively connected to US operations and not reinvested, applied on top of the federal corporate rate. For most European companies of any meaningful scale, the subsidiary is the cleaner answer. Branches make sense in narrow cases, usually short-duration projects or exploratory presences unlikely to generate meaningful profit.

Why sales tax is not the problem European companies think it is

Sales tax is the area where European companies most consistently underestimate US complexity. The instinct is to map US sales tax onto European VAT. The two operate on different architectures, and the differences cost money.

VAT is an EU-level harmonized tax with broadly consistent rules across member states. Companies above a revenue threshold register once, collect consistently, and reconcile through a single ongoing return. US sales tax operates on a completely different model. It is imposed at the state level, with local add-ons, different tax bases (some states tax digital goods, others do not), different exemption rules, different filing frequencies, and different registration requirements.

Since the 2018 US Supreme Court decision in South Dakota v. Wayfair, states have been allowed to require out-of-state sellers to collect sales tax once they cross defined economic thresholds, typically 100,000 dollars in sales or 200 transactions into that state within a year. For a European SaaS company, the practical effect is that scaling into the US creates filing obligations without any need for physical presence. Reaching a few hundred customers in Texas, or crossing a revenue threshold in New York, triggers ongoing registration, collection, and remittance duties in that state.

In practice, many European companies end up with sales tax obligations in fifteen, twenty, or thirty states without realizing it. The liability is cumulative. Each state’s audit clock runs separately. When a tax authority eventually catches up, the exposure includes uncollected tax, interest, and penalties going back to the date the threshold was first crossed. Voluntary disclosure programs exist in most states, but they usually require the company to come forward before being contacted, which is the opposite of the strategy most companies end up following.

A generalist bookkeeper cannot run this surface. The realistic options are dedicated sales tax software integrated with the billing system (Avalara and TaxJar are the two most common platforms) or a specialist firm capable of monitoring nexus thresholds, handling state registrations, and running ongoing filings across an expanding footprint. Neither is cheap. The cost of operating without either rises non-linearly with revenue.

Compliance that keeps showing up

Beyond the structural layers, a set of recurring compliance obligations catches European operators repeatedly, because none of them have a clean European equivalent.

Form 1099 is the most common surprise. Any US-based business that pays a non-employee service provider more than 600 dollars in a year must issue the contractor a Form 1099-NEC. Freelancers, consultants, and small service vendors all qualify. European companies used to handling independent contractors under looser documentation requirements often discover their US subsidiary has a backlog of missed 1099 filings, each of which carries a per-form penalty. The fines are small individually. They compound fast.

Estimated tax payments are another recurring trap. In most European jurisdictions, corporate tax is reconciled and paid once a year. The US requires quarterly estimated payments from both corporate entities and individual shareholders with non-W-2 income. Miss a payment or underestimate it, and the IRS adds an underpayment penalty. The rate has hovered around 8% recently. European founders who draw distributions from a US entity, or who receive K-1 pass-through income, frequently miss estimated payments in their first year of US operations. The penalty assessment then lands with the April reconciliation.

Payroll across state lines is the third category. A US company with remote employees in multiple states must register for payroll tax in each of those states, handle state-specific withholding rates, and file separate returns. This applies even to a single employee living in a state where the company has no other presence. The overhead of tracking where employees physically work on which days, then setting withholding to match, is one of the reasons US payroll providers such as Gusto, ADP, and Rippling command the prices they do. European companies that try to run US payroll through a European bookkeeper almost always end up non-compliant within the first year.

What the successful entrants do differently

The pattern across all of these areas is the same. European companies assume the US market has higher customer willingness to pay, which offsets the operational friction. That math usually works, but only when the friction is genuinely understood and priced into the expansion plan. When compliance and tax obligations are treated as an afterthought, the margin captured from higher US price points disappears into remediation costs, penalties, and rework inside the first two years.

Companies that get this right share one characteristic. They engage US-based specialist advisors before entering the market, not after. They treat the tax and compliance setup as a strategic decision with the same weight as market selection or product localization. They build the ongoing relationship with a firm that can flag issues as they surface, not only at year-end. The cost of that approach is real. The cost of skipping it is larger, compounds faster, and is considerably harder to unwind.

For European board members watching a US expansion from outside, the signal to look for is straightforward. Which executives on the US launch team have hands-on experience with state-by-state filings, quarterly estimated payments, and cross-border withholding? If the honest answer is that the team is leaning on one person who “handles tax,” the expansion is underweighting a line item that will eventually assert itself, usually during a quarter where the business can least afford the distraction.