Which states are SST member states?

Twenty-four states are SST member states as of 2026. For remote sellers with nexus in these states, membership means compliance can be handled for free through a Certified Service Provider, registration, calculation, filing, and remittance, all covered by the state rather than the seller.

The 24 SST member states

These 24 states represent a significant share of where mid-market ecommerce sellers actually have nexus. Washington, Ohio, Michigan, Indiana, Wisconsin, Tennessee, and North Carolina are among the most commonly crossed economic nexus thresholds for brands selling nationally.

What SST member status means for a seller

When a state joins the SST program, it agrees to:

• Conform its tax rules to the SST Agreement’s common definitions and simplified rate structures
• Accept a unified registration: sellers register for all SST states through a single application instead of individually
• Fund the cost of compliance: member states pay Certified Service Providers directly out of collected revenue, so qualifying sellers pay nothing

For a remote seller in SST states, this translates to: no per-filing fees, no registration fees per state, and no per-state compliance bills for SST state filings, as long as you enroll through a CSP.

The major states that are not SST members

Seventeen states plus Washington D.C. are not SST members. This includes some of the largest sales tax states:

Non-SST states with significant sales tax obligations for ecommerce sellers:

• California
• Texas
• New York
• Florida
• Illinois
• Pennsylvania
• Colorado
• Arizona
• Massachusetts
• Louisiana

Compliance in non-SST states is not covered by the program. Sellers with nexus there pay for compliance normally, your provider charges a per-filing fee for each non-SST state, regardless of your SST status.

Who qualifies for free compliance in SST states

The free compliance model applies to remote sellers: defined as sellers without physical nexus in the state. You’re a remote seller in a state if you have no employees, no inventory, no office, and no other physical presence there.

Your economic activity in the state (crossing the sales threshold) is sufficient to create nexus and trigger compliance obligations. SST membership means those obligations are covered.

If you have physical nexus in an SST state — FBA inventory in a fulfillment center, a remote employee, or any other physical presence, you still need to register and file in that state. However, the CSP compensation model that makes compliance free for remote sellers may not apply in the same way for states where you have physical presence. Confirm with your CSP how physical-nexus SST states are handled and whether any fees apply.

How SST enrollment works

You enroll through a Certified Service Provider. The CSP submits your registration to the SST Governing Board, which covers all 24 SST member states where you have nexus in a single application. Your CSP then handles ongoing calculation, filing, and remittance in those states each month.

The only providers who can deliver truly free SST compliance are Certified Service Providers. As of 2026, the five active CSPs are TaxCloud, Avalara, Sovos, Avior, and AccurateTax. Providers who are not CSPs (including TaxJar, Numeral, and Kintsugi) cannot offer the free-filing benefit, and they charge per-filing fees for SST states the same as non-SST states.

Related: Why won’t Avalara and TaxJar tell me about SST benefits?

One trade-off to know before enrolling

SST requires monthly filing in all enrolled states, regardless of sales volume. If you’d otherwise qualify for quarterly or annual filing frequency in some of those states, SST enrollment means you file monthly everywhere. For most mid-market sellers, this isn’t a practical issue (your CSP handles the monthly filings) but it’s worth knowing going in.

Related: Why does SST require monthly filing even if my sales volume is low?