Blog/US Business Setup

US Sales Tax Economic Nexus for Overseas E-commerce & SaaS Companies

A comprehensive state sales tax compliance masterclass for international e-commerce sellers, Shopify merchants, Amazon FBA brands, and SaaS founders on Wayfair economic nexus thresholds and permit registration.

ADVAQ US Sales Tax Advisory Team
16 Min Read Β· Updated July 2026
Wayfair Economic Nexus Compliant
Economic Nexus Key Rules
Wayfair Supreme Court Ruling

States can require foreign sellers with zero physical presence to collect state sales tax if they cross economic sales thresholds.

$100,000 Threshold Standard

Most states enforce an Economic Nexus threshold of $100,000 in gross annual sales or 200 separate transactions into that state.

Amazon Marketplace Facilitator

Amazon automatically collects sales tax on FBA sales. Independent Shopify & Stripe sellers must handle registration manually.

SaaS & Digital Goods Taxability

SaaS and digital software are taxable in ~30 US states (e.g. Texas, New York, Pennsylvania).

1. The Wayfair Supreme Court Ruling & Economic Nexus

In June 2018, the US Supreme Court issued a landmark ruling in South Dakota v. Wayfair, Inc., eliminating the long-standing physical presence requirement for state sales tax collection.

Today, 45 US states and Washington D.C. enforce Economic Nexus laws. Under these statutes, if your overseas e-commerce store or SaaS platform sells goods or services to customers within a US state and exceeds that state's economic revenue or transaction thresholds, your foreign entity is legally obligated to register for a state sales tax permit, calculate sales tax at checkout, and remit those funds quarterly.

2. State-by-State Revenue & Transaction Threshold Breakdown

Economic Nexus thresholds vary across individual US states:

Standard $100,000 / 200 Transaction Threshold States

The majority of US states (including Texas, Florida, Illinois, Georgia, and Ohio) enforce an economic nexus threshold of $100,000 in gross annual sales OR 200 separate transactions into the state during the current or preceding calendar year.

High Threshold States ($500,000 Rules)

Economic powerhouse states like California and New York enforce higher thresholds of $500,000 in gross annual sales into the state before requiring foreign sellers to register and collect sales tax.

3. Comprehensive State Economic Nexus & Taxability Matrix

Detailed side-by-side comparative analysis of key state nexus rules:

US StateRevenue ThresholdTransaction CountSaaS Taxability
California$500,000No Transaction ThresholdExempt (Not Taxable)
Texas$100,000No Transaction ThresholdTaxable (80% Rate)
New York$500,000AND 100 TransactionsTaxable Software
Florida$100,000No Transaction ThresholdExempt (Not Taxable)

US SALES TAX ADVISORY

Get Your US Sales Tax Permits with ADVAQ

ADVAQ conducts state economic nexus audits, registers sales tax permits across all 50 states, and integrates automated tax collection with Stripe and Shopify.

4. Amazon vs Shopify: Marketplace Facilitator Laws

If you sell physical products primarily via Amazon FBA, eBay, Etsy, or Walmart Marketplace, state Marketplace Facilitator statutes require the platform itself to automatically calculate, collect, and remit sales tax on your behalf.

However, if you operate an independent Shopify store, WooCommerce site, or custom Stripe SaaS checkout, you are the merchant of record. You are solely responsible for monitoring your sales volume in every state, registering for state sales tax permits when thresholds are met, and filing quarterly tax returns.

5. Taxability of SaaS & Digital Software Products in the US

The taxability of Software-as-a-Service (SaaS), cloud software, and digital downloads varies dramatically by state:

  • States That Tax SaaS: Texas, New York, Pennsylvania, Washington, Massachusetts, and Connecticut treat cloud SaaS as tangible personal property or taxable data processing services.
  • States Exemption for SaaS: California, Florida, Georgia, Virginia, and North Carolina classify un-customized remote SaaS as non-taxable services.

6. How Foreign Sellers Register for State Sales Tax Permits

Before collecting sales tax from US customers in any state, you must apply for a Sales Tax Permit with that state's Department of Revenue using your US LLC EIN and incorporation details. Collecting sales tax without an active permit is illegal.

Once registered, you enable automated sales tax calculation in Shopify or Stripe Tax, and submit periodic (monthly or quarterly) tax returns to remit collected funds.

Frequently Asked Questions

US SALES TAX SOLUTIONS

Manage US Sales Tax Compliance with ADVAQ

Economic nexus auditing, state sales tax permit registration, Shopify/Stripe automated setup, and quarterly filings handled by ADVAQ.