State Nexus: When Your Italian Company Owes Taxes in Multiple U.S. States

One of the most common misconceptions among Italian groups entering the U.S. market is that their tax obligations are limited to the federal level and the state where they incorporate. In reality, the U.S. state tax system creates a separate layer of compliance that can be more complex — and more costly — than the federal layer.

The concept at the center of this complexity is nexus: the threshold of connection between a business and a state that gives that state the right to impose taxes and require filings. For Italian companies, particularly those distributing products across multiple states or employing people in different locations, nexus analysis is not optional — it is fundamental to understanding the company's true tax position.

1. What Creates Nexus

Nexus can be established in two ways: through physical presence or through economic activity.

Physical Nexus

The traditional standard. A company has physical nexus in a state if it has:

• an office, warehouse, or other physical facility in the state
• employees working in the state (including remote workers)
• inventory stored in the state (including at third-party fulfillment centers like Amazon FBA)
• sales representatives regularly conducting business in the state
• equipment or property located in the state

For Italian companies, a common trigger is hiring a U.S.-based employee in a state different from the state of incorporation. For example, an Italian company incorporated in Delaware with a sales manager based in California has created nexus in California — regardless of where the company's headquarters are.

Economic Nexus

Since the 2018 Supreme Court decision in South Dakota v. Wayfair, states can establish nexus based on economic activity alone — without any physical presence. The most common thresholds are:

• $100,000 in sales into the state during the year, or
• 200 separate transactions with customers in the state

These thresholds vary by state, and some states have adopted different amounts. The Wayfair decision primarily applies to sales tax, but an increasing number of states are applying economic nexus standards to income tax as well.

For Italian companies selling products across the U.S. — whether through direct distribution, e-commerce, or wholesale channels — economic nexus can create obligations in dozens of states simultaneously.

2. Income Tax Nexus

When a company has income tax nexus in a state, it must file a state income tax return and pay tax on the portion of its income attributable to that state. The method for determining how much income is taxable in each state is called apportionment — most states use a formula based on the percentage of the company's sales in that state relative to its total sales.

Key points for Italian-owned subsidiaries:

• State income tax rates range from 0% (Texas, Nevada, Wyoming, and others) to over 10% (New Jersey, California, Pennsylvania)
• Some states impose franchise taxes or gross receipts taxes instead of or in addition to income tax
• Most states require quarterly estimated tax payments, similar to the federal system
• Filing requirements exist even in years when the company has a loss — the state still requires a return

The interaction between state income taxes and federal taxes adds complexity. State income taxes are generally deductible on the federal return, and some states allow credits for taxes paid to other states — but the calculations can be intricate, particularly for companies operating in many states.

3. Sales Tax Nexus

Sales tax is separate from income tax and applies to the sale of tangible goods and certain services. If a company has sales tax nexus in a state, it must:

• register for a sales tax permit in that state
• collect sales tax from customers on taxable transactions
• file periodic sales tax returns (monthly, quarterly, or annually depending on volume)
• remit the collected tax to the state

The challenge for Italian companies is threefold. First, each state (and often each city and county) has its own tax rates, rules about what is taxable, and exemption structures. Second, the economic nexus thresholds mean that a company can trigger obligations in a new state simply by growing its sales — without any intentional expansion. Third, many Italian groups are unfamiliar with the concept of a consumption tax collected by the seller, as the Italian VAT system operates differently.

The penalties for not collecting and remitting sales tax can be severe, and in most states the liability falls on the seller — meaning the company owes the tax even if it failed to collect it from the customer.

4. Payroll Tax Nexus

Any state where the company has employees creates payroll tax obligations. This includes:

• state income tax withholding from employee wages
• state unemployment insurance contributions
• workers' compensation insurance (required in most states)
• local payroll taxes in certain jurisdictions (New York City, San Francisco, and others)

For Italian companies with remote employees or multi-state operations, the payroll tax landscape can be surprisingly complex. An employee working from home in a state different from the company's office may create both payroll tax and income tax nexus in that employee's state.

5. Why This Matters More Than Italian Groups Expect

In Italy, the tax system is national — IRES and IRAP are applied uniformly, and there is no equivalent of the U.S. state-by-state compliance burden. Italian CFOs and commercialisti are often unprepared for the volume of filings and the variability of rules across states.

To illustrate: an Italian company that incorporates in Delaware, has an office in New York, employs a sales representative in California, stores inventory at a fulfillment center in New Jersey, and sells products online to customers in 30 states may have:

• federal income tax filing: 1
• state income tax filings: 4–6 (depending on income tax nexus thresholds)
• sales tax filings: 20+ (monthly or quarterly in each state with economic nexus)
• payroll filings: 3 states
• annual reports and franchise tax filings: multiple states

This compliance volume is significant and needs to be factored into the cost of operating in the United States. It is not unusual for the state compliance burden to exceed the federal compliance burden in terms of both cost and complexity.

6. What to Do About It

Our recommended approach for Italian companies entering the U.S. market:

• Conduct a nexus study before operations begin — understand where your company will have obligations based on its planned activities, employees, and sales channels
• Register proactively — it is far better to register voluntarily than to be discovered by a state and face back taxes, penalties, and interest
• Use automation for sales tax — software platforms (Avalara, TaxJar, Vertex) can calculate, collect, and file sales tax across multiple states, reducing the manual burden significantly
• Revisit nexus annually — as the business grows and enters new states or hires new employees, the nexus profile changes. What was true in year one may not be true in year three
• Factor state taxes into pricing and planning — the combined state tax burden should be part of the financial model, not an afterthought

Closing Observations

State nexus is not an exotic tax concept — it is a practical reality that affects every Italian company operating in the United States. The key is to treat it as a known and manageable cost, not as a surprise that surfaces during an audit or an expansion into a new state.

With proper planning, the right tools, and a clear understanding of where obligations exist, the state tax burden is predictable and controllable. Without it, the risk of penalties, back taxes, and operational disruption is real.

This article is for general informational purposes and does not constitute tax or legal advice. Specific situations should be evaluated on a case-by-case basis.