Understanding your sales tax nexus by state obligations has become critical for businesses selling across multiple jurisdictions. Following the landmark Wayfair decision summary, states rapidly implemented economic nexus laws that require remote sellers to collect and remit sales tax based on revenue or transaction thresholds rather than physical presence alone.
A comprehensive multi-state sales tax nexus study helps businesses identify where they have triggered nexus, assess their exposure, and develop a compliance strategy before states come knocking. This guide covers everything you need to know about conducting a nexus study in 2026.
What Is a Sales Tax Nexus Study?
A sales tax nexus study is a comprehensive analysis of your business activities across all states to determine where you have established sales tax nexus. Nexus represents the connection between your business and a state that requires you to register, collect, and remit sales tax.
Before 2018, nexus was primarily based on physical presence—having employees, offices, or inventory in a state. The South Dakota v. Wayfair decision fundamentally changed this landscape, allowing states to impose economic nexus thresholds based solely on sales volume or transaction counts.
Physical Nexus vs Economic Nexus: Understanding the Difference
Modern nexus analysis requires understanding both traditional physical nexus and newer economic nexus standards.
Physical Nexus Triggers
Physical nexus still matters and includes:
- Having offices, warehouses, or retail locations
- Employing staff or sales representatives in a state
- Storing inventory through third-party logistics (3PL) providers
- Attending trade shows or conducting in-person sales activities
- FBA sales tax nexus for Amazon sellers using Fulfillment by Amazon
Economic Nexus Thresholds
Economic nexus laws vary by state but typically trigger when you exceed:
- $100,000 in annual sales revenue
- 200 separate transactions in a calendar year
Some states use different thresholds. For comprehensive details, see our economic nexus thresholds guide.
Why Your Business Needs a Nexus Study
Many businesses unknowingly trigger nexus in multiple states. Common scenarios include:
Ecommerce Sellers
If you sell through your own website or platforms like Shopify, you likely have customers across dozens of states. Without realizing it, you may have crossed economic thresholds in multiple jurisdictions. Our ecommerce sales tax compliance guide provides detailed guidance for online sellers.
Amazon FBA Sellers
Using Amazon’s Fulfillment by Amazon (FBA) program creates physical nexus wherever Amazon stores your inventory. This often results in nexus in 20+ states without the seller even realizing it. Understanding FBA sales tax nexus is essential for marketplace sellers.
SaaS Companies
Software-as-a-Service providers face unique challenges because SaaS sales tax nexus by state varies dramatically—some states tax SaaS as tangible personal property, others as services, and some exempt it entirely.
Conducting a Multi-State Nexus Study
Step 1: Gather Transaction Data
Collect sales data for the past 3-4 years, including:
- Ship-to addresses for all orders
- Gross sales revenue by state
- Transaction counts by state
- Marketplace sales versus direct sales
Step 2: Review State Economic Nexus Laws
Compare your sales data against each state’s economic nexus thresholds. Remember that thresholds change, so use current requirements. Our sales tax nexus by state 2026 resource provides current threshold information.
Step 3: Analyze Physical Presence
Document any physical activities that might create nexus:
- Employee locations
- Inventory storage (including 3PL and FBA)
- Independent contractors or affiliates
- Trade show attendance
Step 4: Consider Special Nexus Types
Beyond physical and economic nexus, examine:
- Click-through nexus laws — referrals from in-state websites
- Affiliate nexus — relationships with in-state businesses
- Cookie nexus — software downloads in certain states
Nexus Lookback Period and Exposure Assessment
Most states can audit 3-4 years of returns, but the nexus lookback period for unregistered sellers can extend further. When you conduct a nexus study, you must assess:
- How long you’ve had nexus in each state
- Total uncollected tax exposure
- Penalty and interest accumulation
- Voluntary Disclosure Agreement (VDA) eligibility
If you discover significant exposure, a Voluntary Disclosure Agreement (VDA) can help limit lookback periods and reduce penalties.
Marketplace Facilitator Laws Impact
Since 2019, most states enacted marketplace facilitator laws requiring platforms like Amazon, eBay, and Walmart to collect tax on behalf of third-party sellers. While this simplifies compliance for marketplace sales, you remain responsible for:
- Sales through your own website
- Economic nexus created by marketplace sales (still counts toward thresholds)
- Registration requirements even if marketplace collects
Partner Resources for Nexus Studies
Conducting a thorough nexus study requires expertise. Our partners at Abaca Tax specialize in multi-state nexus analysis and can help identify your exposure quickly and accurately. For comprehensive state-by-state guidance, States Sales Tax provides detailed resources on nexus requirements across all jurisdictions.
If you’re wondering do I need to collect sales tax, a professional nexus study will give you definitive answers.
Streamlined Sales Tax (SST) States
The Streamlined Sales Tax (SST) states offer a simplified registration process for businesses needing to register in multiple states. Through the Streamlined Sales and Use Tax Agreement, you can register in 24 member states with one application, reducing administrative burden.
When to Hire a Sales Tax Expert
While some businesses can conduct basic nexus analysis internally, consider hiring a sales tax consultant near me when:
- You sell in 10+ states
- You have complex physical presence factors (FBA, 3PL, remote employees)
- You suspect significant uncollected tax exposure
- You’re facing an audit or have received nexus inquiries
Professional sales tax nexus study cost varies based on complexity but typically ranges from $2,500 to $15,000—a small investment compared to potential penalties and back taxes.
Conclusion
A multi-state sales tax nexus study is essential for any business selling across state lines in 2026. The post-Wayfair landscape means economic nexus can trigger unexpectedly, creating compliance obligations in states where you have no physical presence.
By proactively assessing your nexus profile, you can register in required states, implement proper collection procedures, and avoid costly penalties. For businesses with historical exposure, exploring a Voluntary Disclosure Agreement (VDA) through qualified sales tax compliance services can minimize financial impact.
Don’t wait for a state audit to discover your nexus obligations. Conduct a comprehensive nexus study today and ensure your business remains compliant across all jurisdictions.
Need help with your nexus study? Contact our partners at Abaca Tax for expert assistance, or visit States Sales Tax for comprehensive state-by-state resources.