Sales tax compliance is a risk that generally flies under the radar. Many CPA and accounting professionals are aware of the risk that sales tax compliance represents, but addressing it with clients can be challenging. Without a concrete starting point, the conversation often doesn’t happen at all. 

A nexus study changes that dynamic. It gives your firm a tool rather than a pitch, and it reframes the conversation from "here's something you might want to buy" to "here's something you need to know."

Why the Exposure Is Real

The 2018 South Dakota v. Wayfair decision established that businesses can trigger sales tax obligations based on revenue or transaction volume alone, without any physical presence in a state. Economic nexus thresholds are now in effect across nearly every state, and many have been since 2019 or 2020.

Despite that, a significant share of small and mid-sized businesses still haven't done a formal assessment. They may be collecting in some states and not others. They may have crossed thresholds without realizing it. They may have registered somewhere years ago and stopped monitoring whether that registration is still accurate, or whether new obligations have since emerged.

For accounting firms, this represents both a liability and an opportunity. Clients carrying unaddressed sales tax exposure are at risk of back tax assessments, penalties, and audit scrutiny. Firms that surface that exposure before it becomes a problem are doing exactly the kind of work clients value most.

What a Nexus Study Actually Does

A nexus study is a structured analysis of where a business has sales tax obligations based on its transaction history, revenue by state, physical footprint, and the applicable economic nexus thresholds in each jurisdiction.

It shows, concretely, which states a client has exposure in, how significant that exposure is, and what steps would be required to come into compliance. That kind of specificity is what transforms a vague conversation about "sales tax risk" into a clear advisory engagement with defined scope and real value.

For clients, seeing the data tends to be clarifying in a way that a general discussion rarely is. Exposure that was previously invisible becomes visible. The question shifts from "should we worry about this?" to "what do we do about it?"

Which Clients to Prioritize

Not every client carries the same level of risk. Firms should start by focusing on clients who fit one or more of these profiles:

▶️ Multi-state ecommerce or direct-to-consumer brands, particularly those selling through Shopify, Amazon, or other platforms that generate high transaction volume across many states. These businesses often cross economic nexus thresholds quickly and don't always have systems in place to monitor when that happens.

▶️ SaaS or subscription businesses billing customers across the country. SaaS taxability varies significantly by state, and many founders in this category are operating under the assumption that software isn't taxable. That assumption is wrong in a growing number of jurisdictions.

▶️ Businesses in industries where product taxability is complex, including manufacturing, construction, food and beverage, and healthcare-adjacent products. These clients may be filing in the right states but applying the wrong rates or exemptions.

▶️ Companies that have grown rapidly over the past several years, added remote employees, or expanded their fulfillment footprint. Growth events frequently create new nexus obligations that go unnoticed until a state notice arrives.

How to Position the Conversation

The framing matters. A nexus study works best when it's introduced as a service the firm is proactively offering, not a product the firm is trying to sell.

Something as simple as "we want to make sure you're not carrying any hidden sales tax exposure before it becomes a problem" is enough to open the door. Clients generally appreciate the initiative, and most are curious enough about their own risk profile to engage.

Once the results are in hand, the advisory path forward tends to follow naturally. Clients with no material exposure get confirmation and peace of mind. Clients with meaningful exposure need guidance on registration, back-filing, voluntary disclosure, and ongoing monitoring. That's where a sustained advisory engagement begins.

What Firms Can Do With the Results

The most common outcomes after a nexus study fall into a few categories.

Some clients are largely compliant and simply need better systems for ongoing monitoring as they grow. Others have exposure in states where they haven’t registered, and haven’t been collecting. Other clients may have been filing, but with errors. 

In each case, the nexus study is what makes the path visible. Without it, the conversation stays theoretical.

A Low-Barrier Starting Point

Kintsugi offers a free nexus study through its partner program. Firms can run one for a client at no cost, with Kintsugi handling the analysis. The results give both the firm and the client a clear picture of where exposure exists and what it would take to resolve it.

For firms looking to build out a sales tax advisory practice, or simply deepen their relationships with clients who are growing, this is a practical place to start. The conversation doesn't have to be complicated. It just has to happen.

Learn more about Kintsugi's partner program and how to run a free nexus study for your clients.