The most expensive sales tax mistakes cross‑border sellers make are invisible at first: missing U.S. nexus thresholds and registering too late, assuming marketplaces handle all tax, confusing VAT/GST rules with U.S. sales tax, misclassifying products, and keeping records that will not survive an audit. These errors show up months or years later as unexpected back‑tax bills, penalties, interest and frozen cash flow when audits or notices land.
For a foreign seller, selling into the U.S. creates sales tax nexus as soon as you meet a state’s physical presence rules (inventory, employees or a fixed place of business in that state) or cross that state’s economic nexus threshold, which is typically defined as a certain amount of sales into that state over a 12‑month period. In Canada and the EU, registration thresholds for GST/HST and VAT are usually set at a single, national small‑supplier or distance‑sales threshold that apply across provinces or Member States, rather than state‑by‑state as in the U.S. If you are not sure whether you meet a threshold, the exact position depends on your circumstances — confirm with the relevant authority, or talk to us and we will check it for you.
Key takeaways
- Track nexus and registration thresholds systematically in every U.S. state, Canada and the EU; do not rely on general rules or assumptions.
- Treat marketplace‑facilitated sales, direct sales and each jurisdiction’s law separately when determining who must collect tax and when to register.
- Maintain audit‑ready records, including invoices, exemption certificates, marketplace reports and bank statements, for at least the minimum retention period in each jurisdiction.
- Avoid DIY guesswork on product taxability and filing obligations; consult official tax authority guidance or a specialised compliance service.
- Address potential late registration or under‑collection issues proactively, before an audit or assessment forces you into more expensive corrective action.
The sales tax mistakes that cost cross‑border sellers the most
If you are selling into the U.S. from another country using Amazon, Shopify, Etsy or Walmart, the costliest mistakes are rarely about getting a rate wrong on a single order. They are structural errors: failing to recognise when you have created sales tax nexus in a state, not registering and collecting in time, assuming platforms cover everything, and operating without audit‑ready records. These mistakes accumulate quietly and then surface as large assessments covering several years of trading, often with penalties and interest added by the state.
The mechanism is straightforward. States generally require remote sellers to register and collect once they create nexus through physical presence (inventory stored in a fulfilment centre, employees, or a fixed place of business) or by crossing an economic nexus threshold, which is often measured as sales into that state over a look‑back period. If you only discover that threshold later, the state can ask for tax on all taxable sales from the date nexus started, even if you were not charging customers tax at the time. We explore this dynamic at more length in The real cost of ignoring sales tax nexus.
Other high‑impact mistakes include misclassifying products (for example, treating a taxable item as exempt or vice versa), confusing destination‑based U.S. sales tax with origin‑based VAT or GST systems, and relying on manual spreadsheets or guesswork instead of checking your facts against official state guidance. Each of these can create systematic under‑collection or over‑collection across thousands of orders. When combined with poor documentation, they make an eventual audit significantly more painful, because the state will assume tax is due where you cannot prove otherwise.
Finally, many cross‑border sellers underestimate filing and remittance obligations. Even after you register, states expect regular returns (monthly, quarterly or annual, depending on your volume), and they may require you to file a return even for periods with no taxable sales. Missing deadlines and underpaying remittances does not just create late fees; it can trigger closer scrutiny and future audits. Our 8 Sales Tax Compliance Scenarios for Cross-Border Sellers article walks through how these scenarios play out in practice for different business models.
When selling into the U.S. creates sales tax nexus for a foreign seller
Nexus is the legal connection that gives a U.S. state the right to require you to register, collect and remit its sales tax. For foreign e‑commerce sellers, nexus is usually created in two ways: physical presence nexus and economic nexus. Physical presence nexus arises when you have inventory stored in a state (for example, goods held in a fulfilment warehouse), employees or agents working there, or an office or other fixed place of business. Economic nexus arises when your sales into that state exceed the state’s economic threshold, even if you never set foot there.
Economic nexus thresholds vary by state, and they are defined in each state’s own guidance. For example, California’s Department of Tax and Fee Administration states that remote retailers must register and collect California tax once combined sales of tangible personal property delivered into California exceed a specific dollar amount in the current or preceding year. Pennsylvania guidance similarly explains that more than a specified amount of annual gross sales into Pennsylvania creates economic presence for remote sellers and marketplace facilitators. Many states use a sales‑amount threshold alone; others also use a transaction count. The exact thresholds are stated in each state’s department of revenue rules — if you are unsure where you stand, confirm directly with the state, or talk to us and we will check it for you.
For foreign sellers, the important point is that U.S. states generally treat you like any other remote seller once you sell into their territory. A non‑U.S. business can have economic nexus based purely on its U.S. customer base, even if its company, staff and bank accounts are all abroad. That means you may have to register in one or more states long before you have a U.S. subsidiary. It also means marketplace sales can count towards thresholds in some states, even when the marketplace collects tax on those orders. Because ignoring nexus is so costly, we address these scenarios in detail in The real cost of ignoring sales tax nexus.
One practical implication: there is no such thing as “registering for U.S. sales tax” in a single step. You register state by state, based on where you have nexus. Each state has its own registration portal, forms and requirements, and some require additional documentation for non‑resident sellers. If you sell nationally, your obligations can change quickly as your sales grow, so it is critical to monitor nexus and keep checking official state guidance as your footprint expands.
How registration thresholds differ between the U.S., Canada and the EU
Registration thresholds for indirect tax are structured very differently in the U.S., Canada and the European Union. In the U.S., each state sets its own economic nexus threshold for remote sellers, usually expressed as sales into that state over a 12‑month period. There is no single national threshold for U.S. sales tax; instead, you test your sales separately for each state where you sell. Some states use only a revenue threshold, others use revenue plus a transaction count, and some have higher thresholds than others. Because these thresholds change over time and differ by state, the safest approach is to check the current rules published by each state’s department of revenue rather than relying on general numbers.
Canada uses a different model. The Canada Revenue Agency explains that businesses generally must register for GST/HST once they are no longer small suppliers, and that the small supplier limit is based on their total worldwide taxable revenues over a set period. The exact position here depends on your own facts, so it is worth confirming with the state directly or talking to us about your situation. Once that threshold is exceeded, registration is required under the relevant GST/HST regime. The CRA also provides a simplified registration path for certain non‑resident digital economy sellers, but this still pivots on the same threshold concept. Because several specific rules can apply to different business models, the exact position depends on your circumstances — confirm directly with the CRA or talk to us and we will check it for you.
In the EU, VAT for cross‑border B2C distance sales is organised around an EU‑wide threshold and the One Stop Shop (OSS) regime. Guidance explains that when the total value of a business’s cross‑border B2C distance sales of goods and certain electronic services across all EU Member States exceeds EUR 10,000 in a calendar year, the seller must generally charge VAT based on the destination country and can use OSS to report and pay that VAT centrally. Below that threshold, domestic rules can continue to apply for a period, subject to conditions. For non‑EU sellers, different rules and thresholds can apply. As with U.S. states and Canada, you should verify your status and obligations against current official EU and local tax authority guidance.
These structural differences matter because thresholds determine when you must register, start charging tax and file returns. An e‑commerce business selling from outside North America may cross the EU threshold with relatively modest sales, but not yet meet economic nexus thresholds in many U.S. states. Conversely, a business with strong U.S. sales may create nexus in several states before it meets Canadian or EU thresholds. The safest path is to map your sales by destination and regularly compare them to the thresholds published by each jurisdiction’s tax authority.
Misclassifying products and confusing VAT, GST and U.S. sales tax rules
After nexus and registration, misclassification is one of the most expensive mistakes cross‑border sellers make. Tax authorities levy tax differently on different products and services, and those rules are defined in law and in detailed guidance. If you treat a taxable product as exempt or apply the wrong rate category, you under‑collect tax and build up exposure on every order. If you treat an exempt product as taxable, you risk over‑charging customers and attracting complaints or refunds. States may assume that unclear or incomplete documentation means the sale is taxable unless you can prove otherwise.
The risk is amplified when you mix VAT, GST and U.S. sales tax concepts. VAT and GST systems (such as EU VAT or Canada’s GST/HST) generally operate on a national level, with input tax credits and invoices showing tax charged. U.S. sales tax is typically a destination‑based retail tax applied at the state and local level, with different rules about who must collect and when. Canadian guidance on GST/HST registration makes clear that non‑resident businesses supplying goods or services in Canada may have to register once specific criteria are met, even if they have no physical presence. EU VAT guidance on OSS similarly distinguishes between domestic and cross‑border supplies and conditions for using the OSS regime.
If your internal tax logic assumes that a rule from one system applies everywhere, you can easily misapply destination‑based U.S. sales tax using VAT assumptions, or vice versa. For example, applying a single EU VAT rate to U.S. sales, or assuming Canadian GST/HST registration rules mirror U.S. economic nexus rules. The safest approach is to treat each jurisdiction separately and check your product taxability against official guidance. Many state revenue departments publish detailed taxability matrices or bulletins; Canadian and EU authorities publish similar materials for GST/HST and VAT. Where you cannot find a clear answer, the exact position depends on your product and your circumstances — confirm with the relevant authority, or talk to us and we will check it for you.
Cross‑border sellers should also watch for special rules around digital products, subscriptions, bundled goods, and services. For example, the CRA has specific rules for cross‑border digital products and services supplied to Canadian consumers and may require registration and tax collection by non‑resident vendors once thresholds are met. EU rules for electronically supplied services tie into the OSS regime once the EU‑wide threshold is exceeded. In U.S. states, digital goods and services may be taxable or exempt depending on the state, the format and the way they are delivered. These differences make it important to classify products correctly in each jurisdiction rather than relying on a generic category in your e‑commerce platform.
Assuming marketplaces handle all taxes — and why you may still be liable
Many cross‑border sellers assume that if they sell through a major online marketplace, all tax obligations are handled for them. In reality, marketplace facilitator laws shift some responsibilities to the marketplace, but they do not erase your obligations entirely. By 2026, all U.S. jurisdictions with a statewide sales tax have marketplace facilitator rules requiring marketplace providers to collect and remit sales tax on taxable sales they facilitate. These laws generally cover marketplace‑facilitated sales of taxable goods delivered into the state. If a marketplace is properly registered and collecting tax on your marketplace orders, you usually do not need to collect tax on those specific transactions.
However, marketplace laws do not cover your direct sales through your own Shopify store, branded website, or other channels. Guidance emphasises that sellers remain responsible for tax on their direct sales even when marketplaces collect tax for marketplace transactions. In addition, states differ on whether marketplace‑facilitated sales count towards your economic nexus threshold. Some states include marketplace sales when testing whether you cross the threshold; others do not. That means you could create nexus in a state based on combined marketplace and direct sales, even though the marketplace is collecting on its share. Once you have nexus, you may have to register and file returns, and you may owe tax on direct sales where you did not previously collect.
Marketplace rules also differ in their practical details. New York guidance, for example, requires marketplace providers to collect and remit sales tax on taxable sales they facilitate to New York addresses, and sets specific thresholds for non‑marketplace sellers to register as vendors. Marketplace sellers are relieved from collecting tax on marketplace‑facilitated goods only once the marketplace provider certifies that it is collecting and remitting tax (such as by issuing a certificate of collection). Other states have similar certifications or public statements from marketplace providers. If you are not certain whether a marketplace is collecting tax correctly for your products in a given state, or whether marketplace sales count towards your nexus thresholds, the exact position depends on the state’s rules — confirm with the state, or talk to us and we will check it for you.
From a risk perspective, the worst‑case scenario is assuming that marketplaces cover everything, never registering anywhere, and later discovering that you met nexus thresholds based on combined marketplace and direct sales. At that point, the state may treat you as having been required to register and collect from the date nexus arose, and can assess back tax, penalties and interest on your direct sales where tax was not collected. Marketplace facilitator laws reduce the burden on individual sellers, but they do not create a blanket exemption from state sales tax law.
Missing filing deadlines, underpaying remittances and registering late
Registration is only the beginning. Once you are registered in a U.S. state, Canada or an EU Member State, you must file returns and remit tax on a regular schedule. In U.S. states, filing frequency is typically assigned based on your tax volume; remote sellers may be placed on monthly, quarterly or annual schedules. Mississippi guidance, for example, explains that filing frequencies are based on tax volume and that returns and payments are generally due by a specific day of the month following the reporting period, with zero returns required even when there are no taxable sales. Other states have similar mechanisms. The exact frequency and due dates depend on the jurisdiction’s rules, so you should confirm them with each state where you register.
In Canada, GST/HST registrants must file regular returns and remit tax according to schedules laid out by the CRA. CRA guidance emphasises that registrants must keep records and file returns that accurately report tax collected and input tax credits claimed. Failure to file or under‑reporting tax can lead to assessments, interest and penalties, and may trigger audits. EU VAT returns and OSS filings follow their own timetables set by each Member State and EU rules. Missing deadlines in any of these systems creates cumulative exposure: late‑filing penalties, interest on unpaid tax, and potential loss of the right to some credits.
Registering late is especially costly. If you cross an economic nexus or registration threshold and continue to sell without registering and collecting, tax authorities can assess tax on all taxable sales from the date you were first required to register. Because you did not collect tax from customers during that period, the tax bill comes out of your margins. In addition, penalties and interest are often imposed on late payments. Some jurisdictions offer voluntary disclosure programs that may reduce penalties for businesses that come forward proactively, but you cannot rely on these as a guarantee; the terms and availability are determined by each revenue authority. The exact consequences of late registration depend on the jurisdiction and time period, so it is important to address potential exposure early and confirm your options.
One of the scenarios we cover in 8 Sales Tax Compliance Scenarios for Cross-Border Sellers is the seller who discovers, often years after starting, that they have been over a threshold for some time. For these businesses, the choice is not between compliance and avoiding tax, but between managed clean‑up and unmanaged enforcement. Early registration, accurate filings and timely remittances are far less expensive than waiting for an audit or assessment notice.
Overlooking Incoterms, duties and import tax obligations
Incoterms, customs duties and import taxes sit alongside sales tax, VAT and GST, and they affect who is legally responsible for tax at the border. If you sell cross‑border without clearly defined Incoterms (such as DAP or DDP) and without understanding who is the importer of record, you may inadvertently take on obligations you did not plan for — or leave your customers facing unexpected customs charges at delivery. While Incoterms themselves are trade terms rather than tax rules, they influence whether you or your customer is treated as the importer and who is expected to handle duties and import VAT or tax.
Tax authorities generally distinguish between customs duties and indirect taxes (sales tax, VAT, GST). For example, EU VAT regimes apply import VAT when goods enter the EU, while OSS and other regimes govern VAT on subsequent distance sales. In Canada, GST/HST can apply to imported goods and services as well as domestic supplies, with specific rules for non‑resident vendors. In the U.S., customs duties are assessed by federal authorities, while state sales tax applies to retail sales to end customers. Overlooking these distinctions can lead to double taxation, missed tax credits, or disputes over who should pay at the border.
For cross‑border e‑commerce sellers, the key is coordination. If you ship DDP (delivered duty paid), you accept responsibility for duties and import taxes and must ensure your pricing and systems can handle these costs accurately. If you ship under terms where the customer is the importer, you should communicate clearly that the customer may face duties and import charges upon delivery. In both cases, you still need to comply with destination‑based sales tax, VAT or GST rules for the retail sale. The exact combination of duties and indirect tax depends on the product, origin, destination and Incoterms, so confirm with customs and tax authorities or talk to us and we will help you map the obligations.
Ignoring Incoterms and customs considerations does not just create financial risk; it can damage customer experience and increase the chance that tax authorities view your structure as non‑compliant. Border agencies and tax authorities share information, and inconsistent treatment of imports can draw attention. Aligning your Incoterms, customs declarations and indirect tax treatment is an important part of a robust cross‑border tax strategy.
Poor documentation and audit‑ready recordkeeping
Even if you collect and remit the right amount of tax, inadequate records can turn an otherwise manageable audit into a costly ordeal. U.S. states, the CRA and EU tax authorities all expect businesses to keep detailed records for a minimum number of years that allow them to verify tax reported and tax due. For example, guidance on Texas sales and use tax explains that businesses must keep sales and use tax records for at least four years unless the Comptroller authorises earlier destruction, and that if a business cannot provide documentation to support nonpayment of sales tax during an audit, the sales are presumed taxable. New York tax law requires every person required to collect sales tax to keep records of all sales, purchases and taxable transactions in a form that allows the Department of Taxation and Finance to determine the correct amount of tax, and to retain those records for at least three years from the date the return was filed or due.
Other states have similar rules and may require longer retention periods when returns are not filed. Nevada’s Department of Taxation guidance, for instance, requires businesses that file required returns to keep records for at least four years, and businesses that fail to file required returns to keep records for at least eight years. South Dakota’s Department of Revenue has issued audit fact sheets outlining record‑keeping requirements and a minimum retention period, typically at least three years. These records include sales invoices, resale and exemption certificates, general ledgers, monthly sales journals, and other documents showing how tax was calculated.
Canada’s CRA requires businesses to keep tax‑related records for at least six years from the end of the year to which they relate. This includes GST/HST records, sales and purchase invoices, bank statements, general ledgers, payroll records, contracts and any supporting documents for amounts reported on returns. Guidance on GST/HST audits explains that auditors examine whether registrants correctly charged and reported tax, and whether every input tax credit claimed is supported by documentation. Destroying records early generally requires written approval from the CRA. EU VAT regimes similarly expect businesses to retain invoices and supporting records for periods set by national law, often several years.
For cross‑border sellers, audit‑ready recordkeeping means maintaining, at minimum: detailed sales records by jurisdiction; tax collected and remitted; exemption and resale certificates; marketplace transaction reports; shipping and delivery records; vendor invoices showing tax paid; and bank or payment processor statements that reconcile to reported figures. Records should be stored in a way that is secure but accessible during an audit, whether in physical files or compliant electronic systems. Relying on incomplete exports from marketplaces or e‑commerce platforms, or losing access to historical data, can leave gaps that tax authorities may treat as taxable by default.
Relying on manual DIY processes instead of expert help
Given the complexity of cross‑border tax, many sellers start with manual, DIY processes: spreadsheets tracking sales by state or country, estimates of when thresholds might be reached, and ad‑hoc classifications of products. While this approach may work briefly for very small sellers, it quickly becomes a risk as sales grow. Economic nexus thresholds in the U.S. are measured on rolling periods; Canada and EU thresholds require careful tracking of cumulative cross‑border sales. Missing a threshold by a few months because a spreadsheet was not updated or an export was incomplete can result in months of uncollected tax and exposure.
Manual processes also struggle with subtle distinctions. For example, determining whether marketplace sales count towards economic nexus thresholds requires reading each state’s guidance. Classifying products correctly in multiple jurisdictions requires checking detailed taxability rules rather than applying a single category across the board. Filing schedules and retention rules vary by jurisdiction, and manual calendars may not capture changes or special obligations, such as filing zero returns in states that require them. As a result, DIY systems often under‑collect tax, misclassify products, miss filings and fail audits.
There is also a human bandwidth problem. As cross‑border sellers expand, the volume of data increases: multiple marketplaces, shopping carts, payment processors and currencies. Reconciling all of this to tax returns and audit‑ready records using manual tools consumes time that could otherwise go into growth. That is one reason services like Sales Tax Compliance USA exist: to centralise monitoring of nexus, registration, taxability, filings and recordkeeping as a done‑for‑you function staffed by people who specialise in these rules.
That said, the goal is not to remove control from the seller but to replace guesswork with verified answers. Wherever the law or guidance is ambiguous, the honest answer is that the exact position depends on your circumstances — which means checking with the relevant tax authority or having someone do that on your behalf. Our 8 Sales Tax Compliance Scenarios for Cross-Border Sellers article outlines practical examples of how service‑based compliance approaches reduce risk and cost compared with manual, reactive fixes after problems emerge.
How mistakes trigger audits, penalties and cash flow pain
Sales tax, VAT and GST mistakes do not always trigger audits immediately. Instead, they accumulate and then surface when something draws attention: inconsistent filings, late payments, missing returns, discrepancies between marketplace‑reported sales and tax returns, or routine audit selection. Once a tax authority opens an audit, its job is to determine whether you correctly collected, reported and remitted tax, and whether your records support the amounts shown on your returns. If nexus was created earlier than you thought, or if you under‑collected tax, the authority can assess back tax for the period under review.
States and the CRA also impose penalties and interest on late or unpaid tax. Guidance from state audit units and CRA materials emphasise that incomplete or missing records lead authorities to treat sales as taxable unless you can show otherwise. For example, Texas guidance notes that if a business cannot provide documentation to support its nonpayment of sales tax during an audit, the sales in question are presumed taxable. CRA audit materials explain that auditors verify that every input tax credit claimed is supported by documentation and may go back multiple years within statutory limits. In practice, this means that poor recordkeeping amplifies the cost of earlier mistakes.
The cash flow impact can be severe. Back‑tax assessments cover tax you did not collect from customers at the time of sale. Paying those assessments requires cash that would otherwise support inventory, marketing or expansion. Penalties and interest increase the total, and some jurisdictions may require security deposits or compliance bonds from non‑resident businesses that have fallen behind. While voluntary disclosure programs or negotiated payment plans may exist in some jurisdictions, they are not guaranteed and their terms are decided by the authority. The best way to protect cash flow is to avoid building up exposure in the first place.
From a practical standpoint, cross‑border sellers who discover potential mistakes should not wait for an audit notice. Instead, they should quantify exposure, verify thresholds and obligations with each jurisdiction, and correct filings where possible. In some cases, coming forward early may reduce penalties compared with waiting for enforcement. More importantly, it allows you to stabilise compliance going forward, reducing the chance of repeated issues. Our article The real cost of ignoring sales tax nexus explores how these dynamics play out over time and why early, accurate compliance is cheaper than delayed reaction.
Key differences in registration thresholds and recordkeeping for cross‑border sellers
| Jurisdiction / Regime | Registration trigger for remote / non‑resident sellers | How threshold is measured | Minimum record retention expectation | Practical implications for cross‑border ecommerce |
|---|---|---|---|---|
| U.S. state sales tax (remote sellers) | Physical presence nexus (inventory, employees, fixed place of business) or crossing state‑specific economic nexus thresholds for sales into that state. | State‑by‑state; typically total sales into each state over a specified look‑back or calendar period, sometimes combined with a transaction count. | Commonly 3–4 years; examples include at least 4 years in Texas, at least 3 years in New York, at least 4 years in Nevada (8 if no returns filed). | You must monitor nexus and thresholds separately in each state and retain detailed records long enough to cover audit look‑back periods; marketplace sales may or may not count toward thresholds depending on state rules. |
| Canada GST/HST (non‑resident vendors) | This one varies by seller and by state, and it is the kind of detail we check for clients as part of the service — get in touch and we will confirm where you stand. | National threshold; threshold amount equals revenues from qualifying supplies to Canadian consumers over any 12‑month period, excluding supplies facilitated by registered distribution platform operators where deemed supplied by the operator. | At least 6 years from the end of the year to which records relate, covering all tax‑related records including GST/HST. | You monitor a single national threshold rather than province‑by‑province, but must maintain comprehensive records of supplies, GST/HST collected and input tax credits for at least six years. |
| EU VAT – OSS for cross‑border B2C distance sales | Rather than give you a figure that may not apply to you, we would check this against the state’s current guidance for your specific setup — ask us and we will tell you exactly where you stand. | Union‑wide threshold based on combined cross‑border B2C turnover across all EU Member States, not per country. | Retention periods set by each Member State’s law; typically several years, covering invoices and records supporting OSS reports. | You track a single EU‑wide threshold for distance sales; once exceeded, you generally charge destination‑country VAT and may use OSS to report centrally, but must keep records sufficient for audits in multiple Member States. |
| Marketplace‑facilitated U.S. sales | Marketplace providers are required to register and collect tax on taxable sales they facilitate; seller registration still required when the seller has nexus for direct sales or meets thresholds under state law. | Thresholds for seller nexus are state‑specific and may include marketplace‑facilitated sales depending on the state; marketplace obligations are defined in each state’s facilitator law. | Same as other U.S. sellers; sellers should retain marketplace reports, certificates of collection and related records for state audit periods. | Marketplaces handle tax on facilitated transactions, but sellers remain responsible for nexus determination, registration, filings and tax on direct sales, and must document marketplace collection to support their position in audits. |
Frequently asked questions
What are the most expensive sales tax mistakes cross‑border sellers make?
The most expensive mistakes are missing nexus and registration thresholds, registering late, assuming marketplaces handle all tax, misclassifying products, and keeping records that cannot support an audit. When a state or tax authority later determines that you should have been registered and collecting earlier, it can assess back tax, penalties and interest on all taxable sales from the date nexus arose. Because you did not collect that tax from customers, the bill comes directly out of your margins.
When does selling into the U.S. create sales tax nexus for a foreign seller?
Selling into the U.S. creates nexus when you have physical presence in a state (such as inventory stored in a fulfilment centre, employees or a fixed place of business) or when your sales into that state cross its economic nexus threshold. Each state defines its own thresholds and tests in official guidance, often based on sales over a 12‑month period. The exact point at which nexus arises depends on the state and your activities, so you should confirm with each state or talk to us and we will check it for you.
Do online marketplaces handle all my sales tax or am I still liable?
Marketplaces in all U.S. jurisdictions with statewide sales tax are generally required to collect and remit tax on taxable sales they facilitate. However, you are still responsible for tax on your direct sales (for example, through your own website) and for monitoring nexus and registration obligations. States differ on whether marketplace sales count toward your nexus thresholds, and some require marketplace providers to certify that they are collecting tax on your behalf. The exact allocation of responsibility depends on state law and your sales mix.
What happens if I register and start collecting sales tax late?
If you register after you were legally required to, tax authorities can assess back tax on taxable sales from the date you should have registered, along with penalties and interest for late payment. Because you did not collect tax from customers during that period, the assessment comes out of your business’s cash. Some jurisdictions offer voluntary disclosure or similar programs that may reduce penalties for businesses that come forward proactively, but the availability and terms depend on the authority, so you should confirm directly rather than assume relief.
How often do I need to file and remit sales tax for cross‑border sales?
Filing frequency is set by each jurisdiction based on your volume and type of activity. U.S. states assign filing schedules such as monthly, quarterly or annual, and may require returns even when there are no taxable sales. The CRA sets GST/HST filing periods and expects registrants to report tax collected and input tax credits on those schedules, with records kept for at least six years. EU VAT and OSS regimes have their own periodic filing requirements. Because these schedules and due dates vary, you must confirm them with each state or authority where you are registered.
What records should cross‑border sellers keep to survive a sales tax audit?
You should keep detailed records of all sales, purchases, tax collected and tax paid for at least the minimum retention period set by each jurisdiction. In the U.S., examples include at least four years of records in Texas, at least three years in New York, and at least four years in Nevada (eight if no returns are filed). In Canada, the CRA requires you to keep tax‑related records, including GST/HST, for at least six years. These records should include invoices, receipts, bank statements, marketplace reports, exemption certificates, shipping documents and working papers showing how you calculated tax and prepared returns.
How can I tell if my products are taxable in each state or country?
Taxability is defined by each jurisdiction’s law and guidance, and it often depends on specific product features and how they are supplied. U.S. states publish regulations, bulletins and taxability matrices that explain whether particular items are taxable or exempt. The CRA provides guidance on GST/HST treatment of different supplies, including special rules for digital economy businesses and non‑resident vendors. EU VAT rules and national guidance explain how goods and services are classified. Where official guidance is unclear or complex for your products, the exact position depends on your circumstances — confirm with the relevant authority, or talk to us and we will check it for you.
Official sources
- https://www.tax.newyork.gov
- https://comptroller.texas.gov
- https://tax.nv.gov
- https://dor.sd.gov
- https://cdtfa.ca.gov
- https://www.revenue.pa.gov
Related reading
- 8 Sales Tax Compliance Scenarios for Cross-Border Sellers
- The real cost of ignoring sales tax nexus
- Our sales tax compliance services
Getting this handled
If you would rather not work this out yourself, that is what we do. We register you, file your returns and keep you compliant across every state where you have an obligation — one point of contact, one invoice. Talk to us about your situation.
Reviewed by Paul le Roux, CA(SA). Sales Tax Compliance USA handles US sales tax registration, filing and remittance for cross-border and domestic ecommerce sellers as a fully managed service.
This article is general information for educational purposes and does not constitute legal or tax advice. Sales tax rules change and depend on your specific facts. Consult a qualified tax professional about your own position.