3 sales tax nexus checks for bookkeeping firms in Chicago and Seattle

What to take away

What economic nexus means for a bookkeeping firm's clients

Economic nexus is a state rule that creates a sales tax collection duty based on sales volume, not physical presence. A client with no office, warehouse or employee in a state can still owe that state tax.

That shifts the bookkeeper's job. You are no longer just recording tax collected on invoices. You are watching whether the client crossed a line, when it crossed, and whether the invoices after that date carried the right tax.

For a firm, the practical unit of work is the client, the state and the measurement period. Illinois measures the preceding four quarters. Washington measures the current or prior calendar year. Those two clocks do not line up, which is why a single spreadsheet rarely works for both.

This is where a firm's operations and workflow guide earns its keep: nexus monitoring is a recurring task with an owner, a due date and a place to record the result. If it lives in someone's memory, it will be missed in the quarter it matters.

Illinois nexus thresholds and reconciliation impact

Illinois economic nexus threshold: remote retailers and marketplace sellers with cumulative gross receipts of more than $100,000, or 200 or more separate transactions, in the preceding four quarters must collect and remit Illinois sales tax.

Two details drive the reconciliation work. First, the test uses gross receipts, so exempt sales and sales for resale count toward the threshold even though they are not taxable. Second, the transaction count alternative means a client with modest dollars but many small orders can cross on count alone.

A Chicago, IL client example: a distributor on the near west side sells packaging components to manufacturers across the Midwest. Most of its Illinois sales are exempt manufacturing purchases supported by resale certificates. The client assumes no collection duty because the taxable total is small.

The gross figure still clears $100,000, so the exemption certificates have to be on file and matched to the invoices.

Reconciliation impact: every exempt Illinois sale now needs a valid certificate in the client's records, and the reconciliation should tie the exempt total to certificates by customer. Missing certificates become tax owed, not a footnote.

Illinois also has local sales tax in Chicago and home rule units, so a single statewide rate does not exist. Reconcile by jurisdiction, not by state total. Rule changes that affect registration and collection duties are indexed in the Federal Register's CFR topics, which is one place to watch.

Washington nexus thresholds and reconciliation impact

Washington sales tax nexus: a remote seller with more than $100,000 in cumulative gross retail sales into Washington in the current or prior calendar year must register with the Department of Revenue and collect retail sales tax. Washington uses a dollar test only, with no transaction count alternative.

Washington also runs a marketplace facilitator law, so sales made through a marketplace are collected and remitted by the marketplace. The seller still needs those sales for its own threshold math. That split is the main source of reconciliation errors for Seattle clients.

A Seattle, WA client example: a subscription software company sells direct through its own site and through a marketplace. The marketplace handles tax on its channel. The direct channel crosses $100,000 in Washington gross retail sales mid-year.

Because Washington measures the current or prior year, the client may already have a duty for the year in which the threshold was crossed, not just the next one.

Reconciliation impact: separate marketplace and direct channel totals, then test the combined gross figure against the threshold. Do not net out refunds or exempt sales when testing. Keep the marketplace's collected tax out of the client's payable so the return does not double count.

Washington's remote-first client base also means employees and contractors may be scattered. Physical presence still creates nexus on its own, so a Seattle client with a single remote employee in another state has a second analysis to run.

Three nexus checks to run before each close

These are the three nexus checks. Run them in order, and record the answer for each client and each state.

Use a short checklist so the same steps run every close:

A firm that runs these checks as SOPs: the daily checklist gets a consistent answer instead of a scramble in the week the return is due.

Manufacturing versus e-commerce client differences

Manufacturing sales tax clients and e-commerce clients hit nexus differently, and the reconciliation differs with them.

A Chicago manufacturer often clears the Illinois threshold on gross receipts while owing little or no Illinois tax, because its sales are exempt. The reconciliation then centers on certificate collection and customer setup, not on the payable.

An e-commerce client in Seattle may owe tax on nearly every direct order and still have no certificates to chase. Its reconciliation centers on channel splits, refunds and the timing of the registration.

Manufacturers also carry inventory and fixed assets across state lines, which can create physical presence nexus in states where they hold property or stock. E-commerce clients rarely hold property but often hold marketplace relationships in several states at once.

Both client types need the same evidence standard. Before a figure goes in the reconciliation, the firm should be able to point to the invoice, the certificate or the marketplace report behind it. That is the same discipline described in the bookkeeping firm local seo checklist, applied to tax rather than cash.

Recording nexus findings in the sales tax reconciliation

The reconciliation is the record. A nexus finding that is not written down is not a finding, because the next preparer cannot see the reasoning.

For each client, keep a nexus schedule with the state, the measurement period, the gross figure, the threshold, the conclusion and the review date. Update it each close, even when nothing changed. The unchanged periods are what prove the firm was watching.

Attach the evidence. For a Chicago distributor, that means certificates and a list of customers still missing them. For a Seattle subscription company, that means the marketplace report and the direct sales total. The schedule should let a reviewer reach the same conclusion without asking the preparer.

Escalate when a threshold is crossed without registration. The client needs to know the exposure, and the firm needs a written instruction on how to proceed. This is a scope question as much as a tax question, and it belongs in the firm's service standards under review so the boundary is clear before the work starts.

Review the schedule as part of service quality checks. A second set of eyes on the threshold math catches the two common errors: using taxable sales instead of gross, and netting marketplace sales out of the threshold test.

Two outside sources help firms keep current. The Federal Register's business and industry feed carries regulatory changes that affect clients across sectors. The USAGov small business hub covers state licensing and operations basics, which is where a newly registered client starts.

Common questions