Sales Tax Nexus in South Dakota: What Online Sellers Need to Know

The Short Answer

South Dakota is where modern economic nexus began — the state's 2016 law was the subject of South Dakota v. Wayfair, Inc. (2018), the Supreme Court case that changed e-commerce compliance for everyone. Today: $100,000 threshold (no transaction count since January 2025), SST member, 4.2% state rate (temporarily reduced from 4.5% through June 2027). SaaS is taxable.

Economic Nexus Threshold

• Dollar threshold: $100,000 in gross revenue from sales into South Dakota
• Transaction threshold: None — eliminated effective January 1, 2025
• Measurement period: Previous or current calendar year
• Effective date: Original law enacted 2016; enforceable June 21, 2018 (Wayfair decision)

Does South Dakota Count Marketplace Sales Toward Your Threshold?

Marketplace facilitators collect and remit on facilitated transactions. Whether facilitated sales count toward your seller threshold should be confirmed — Taxero evaluates this during onboarding.

What Taxable Products Look Like in South Dakota

• Current state rate: 4.2% (reduced from 4.5% effective July 1, 2023)
• ⚠️ Rate reversion: Returns to 4.5% on July 1, 2027
• Local additions: Municipalities add rates; Sioux Falls and Rapid City reach approximately 6%–7% combined
• Groceries: Taxable — South Dakota taxes food/groceries at the full rate (no exemption)
• Clothing: Taxable
• SaaS and digital goods: Taxable. South Dakota follows SST definitions broadly.

How to Register in South Dakota

South Dakota is an SST member:

• SST SSTRS: sstregister.org — preferred path
• Direct: South Dakota DOR online
• Cost: Free

Filing Requirements

Monthly, quarterly, or annual based on liability. Due last day of the following month.

What Happens If You Don't Register

Penalties per SDCL §10-59-6.

How Taxero Handles South Dakota

Taxero applies the current 4.2% rate and has the July 2027 rate reversion (to 4.5%) built into our schedule. SST registration, SST rate files for local rates, SaaS taxability applied. We notify you when the rate change occurs so your collection adjusts automatically.

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