If you crossed a sales tax nexus threshold, you may now have a legal obligation to register, collect sales tax, file returns, and remit tax in that state. The next step is to assess your exposure quickly and avoid delays that could increase penalties or historical liability.
What Happens After You Cross a Sales Tax Nexus Threshold?
Once you cross a sales tax nexus threshold, you may be legally required to register for sales tax in that state and begin collecting and filing sales tax returns.
For many ecommerce businesses, this is the moment where:
- Sales tax becomes much more complex
- Multi-state compliance begins
- Historical exposure may start building
The important thing is to act strategically rather than panic-registering immediately.
The most important point to remember is that crossing a sales tax nexus threshold usually means you must register for sales tax and begin collecting tax in that state but timing, exposure, and registration strategy matter significantly.
What Is a Sales Tax Nexus Threshold?
A sales tax nexus threshold is the level of business activity that creates a sales tax obligation in a state.
This is usually based on:
- Revenue
- Transaction volume
- Physical presence
Once the threshold is exceeded:
- The state considers your business to have nexus
- Sales tax obligations are triggered
Types of Sales Tax Nexus
1. Economic Nexus
Economic nexus is based on sales activity into a state.
Most states use thresholds such as:
- $100,000 in revenue
- $500,000 in larger states
- Transaction count thresholds
Economic nexus is now the most common trigger for online businesses.
2. Physical Nexus
Physical nexus occurs when your business has a physical presence in a state.
This can include:
- Inventory in warehouses
- Amazon FBA inventory
- Employees or contractors
- Offices or fulfilment centres
Physical nexus often creates immediate obligations regardless of sales volume.
Why Crossing Nexus Thresholds Matters
Crossing a nexus threshold means a state may now expect your business to:
- Register for sales tax
- Collect tax from customers
- File returns
- Remit tax payments
If this does not happen:
- Back tax exposure can begin accumulating.
Why Many Businesses Miss Nexus Thresholds
Most businesses do not intentionally ignore sales tax, they simply grow faster than their compliance processes.
This commonly happens when:
- Ecommerce sales increase rapidly
- Businesses expand nationwide
- Marketplace and Shopify sales combine unexpectedly
- Inventory is stored across multiple states
Many businesses only realise they crossed thresholds months later.
What Should You Do After Crossing a Nexus Threshold?
Step 1: Confirm the Threshold Was Actually Exceeded
Review:
- Revenue by state
- Transaction counts
- Marketplace sales inclusion rules
Different states calculate thresholds differently.
Step 2: Determine the Date Nexus Began
This is extremely important because:
- It affects historical exposure
- It determines when collection obligations started
Businesses often overlook this step.
Step 3: Assess Historical Exposure
If you crossed the threshold previously:
- You may already have uncollected sales tax exposure
This could include:
- Tax
- Penalties
- Interest
Step 4: Review Registration Strategy Carefully
Do not automatically register immediately without understanding the implications.
In some situations:
- Voluntary disclosure options may exist
- Strategic timing may reduce exposure
Registration can sometimes impact historical liability discussions.
Step 5: Register and Configure Collection Correctly
Once ready:
- Register with the state
- Configure your ecommerce platform properly
- Begin collecting tax
This may include:
- Shopify tax settings
- Amazon marketplace considerations
- Filing frequency setup
Step 6: Maintain Ongoing Compliance
After registration:
- Filing obligations continue
- Returns must be submitted regularly
Even zero-dollar returns may still be required.
State Economic Nexus Thresholds (2026 Overview)
| State | Revenue Threshold | Transaction Threshold |
| California | $500,000 | None |
| Texas | $500,000 | None |
| Florida | $100,000 | None |
| New York | $500,000 | 100 transactions |
State rules vary significantly, so businesses should monitor thresholds continuously.
What Happens If You Delay Action?
Delaying after crossing a sales tax nexus threshold can significantly increase liability.
Possible consequences include:
- Back tax assessments
- Penalties and interest
- Nexus notices from states
- Audit exposure
States increasingly use the below methods to identify businesses exceeding thresholds:
- Marketplace data
- 1099-K reports
- AI-driven compliance systems
Worked Examples
Example 1: Shopify Seller
- Florida sales exceed $100,000
- Business does not register immediately
Result:
- Historical exposure begins building
- State may later issue a nexus notice
Example 2: Amazon FBA Seller
- Inventory stored in Texas warehouse
- Seller focuses only on economic thresholds
Result:
Physical nexus already existed earlier
Example 3: International Ecommerce Brand
- UK business selling nationwide in the US
- Multiple thresholds exceeded unknowingly
Result:
Multi-state registration and filing obligations triggered
Common Mistakes Businesses Make
- Waiting too long after crossing thresholds
- Assuming marketplace collection removes all obligations
- Registering without reviewing historical exposure
- Ignoring physical nexus triggers
- Not tracking sales by state
These mistakes can become expensive very quickly.
FAQs
What happens immediately after crossing a nexus threshold?
You may become legally required to register and collect sales tax.
How quickly do I need to register?
This varies by state, but delays can increase exposure.
Can states detect when I crossed thresholds?
Increasingly yes, through marketplace and payment processor data.
Should I register immediately?
Not always, review your exposure and strategy first.
What if I crossed the threshold months ago?
You may already have historical liability that needs addressing.
Final Thoughts
Crossing a sales tax nexus threshold is one of the most important compliance moments for an online business.
The key takeaway is once nexus is created, sales tax obligations begin,even if you did not realise you crossed the threshold at the time.
By acting strategically, businesses can:
- Reduce risk
- Limit historical exposure
- Stay compliant as they scale
If your business recently crossed a sales tax nexus threshold, RJM Tax Exemption can help you assess your exposure, determine the best registration strategy, and manage multi-state compliance correctly.
