Nexus — meaning in cross-border tax

Nexus is the connection that gives a sub-national authority — a state, and in Canada a province — the right to tax you. It is created by facts such as employees, inventory or economic activity in that place. The point most people get wrong is the next one: a federal treaty is an agreement between two national governments, and it does not bind a sub-national authority. So a business can be shielded from federal tax in the other country by treaty and still sit squarely within the reach of a state it has nexus with. The treaty analysis and the nexus analysis are separate pieces of work, and the second has to be done jurisdiction by jurisdiction.

Yes. Nexus does not require premises. It can rest on employees present in the state, on stock held there, or on economic activity measured by the volume of business done into the state. Each authority sets its own test and applies its own rules, so the answer can be yes in one state and no in the one next door on identical facts. Because there is no single national register to consult, the practical method is to list where people went, where goods sat and where revenue came from, then test that list against each state's own standard rather than against a general impression of substance.

Often, yes. Inventory is one of the classic nexus facts, and it does not stop being yours because somebody else holds it. Stock sitting in a third-party fulfilment centre is generally still your property in that state, which is how a business that has never visited a place ends up connected to it. The question to answer is not whether you rented the building but whether goods you own were physically present, for how long, and whether they were held for sale. Shipping records and the fulfilment provider's own location reports usually settle it, and they are worth gathering before an authority asks for them.

They can. An employee who crosses a border to visit customers, install equipment or attend a site is a person in that jurisdiction doing your business, and a number of states treat that as enough. What matters is what the person did and how often, not their job title. Sales solicitation is treated differently in some places from installation or repair work, so a single travel log can produce different answers in different states. The difficulty is that travel is arranged by the people travelling and recorded nowhere useful, so the evidence has to be rebuilt from expense claims and calendars later. A contemporaneous record is far cheaper.

By mapping your own facts and then testing them one jurisdiction at a time. Build a single list of where employees were physically present, where inventory was held, where property is owned or leased, and where your sales were delivered. That list is the input to every state's test. No lookup answers it, because each authority defines its own connection and does not adopt another's conclusion — registering in one state does nothing for the next. The reason to do this before anything else is that nexus decides which returns exist at all, and the cost of the answer rises once a jurisdiction has written to you first.

Possibly. Several of the obligations nexus triggers are not taxes on profit. A sales or transaction tax is charged on what you supplied, and some sub-national charges are measured on gross receipts, payroll or capital rather than on income. So a loss-making year can still carry registration, collection and filing duties in a state you are connected to. Treating a loss as a reason not to look is one of the commoner ways a small exposure becomes a large one, because the unfiled periods keep accumulating while the business remains convinced it owes nothing at all.

It can, on two separate fronts, and the second applies even when the first does not. A permanent establishment may arise if the employee has a fixed place of business there or concludes contracts for you. Independently of that, employing someone locally generally brings payroll registration, wage withholding and social security contributions in their country from the first payroll — obligations that do not wait for a permanent establishment finding. Contractor paperwork does not by itself avoid either. See remote work and tax exposure.

In this order. Fix your residence under each country's own rules, and if both claim you, apply the treaty tie-breaker. Identify where each type of income is sourced. Read the article that covers that income type, because it decides who taxes and at what maximum rate. Then claim the relief on the residence-country return, with proof of the foreign tax. Most of the tax people lose to double taxation is lost at the last step, not the first. See how double taxation is relieved.