South Dakota Contractor Excise Tax

What the Contractor Excise Tax Is

South Dakota imposes a 2% excise tax on the gross receipts of prime contractors performing construction services or realty improvements. This is separate from the state's sales tax — it's an additional tax layered on top, levied under SDCL Chapter 10-46A.

"Gross receipts" means everything: labor, contractor-furnished materials, overhead, profit margin, and even the excise tax itself if you pass it along to the customer. Every dollar that flows through the contract gets taxed.

Before you can legally bid on, sign, or perform any construction contract in South Dakota, you need a Contractor's Excise Tax (CET) license from the Department of Revenue. There's no fee to register — you apply through the state's online EPath portal and receive an 8-digit tax number formatted as XXXX-XXXX-ET.

The Bid Factor: Why 2% Isn't Actually 2%

This is where contractors new to South Dakota consistently lose money. The excise tax is calculated on gross receipts, which includes the tax itself if you pass it to the customer. So adding a flat 2% to your bid doesn't fully recover the tax — you'd be paying tax on the tax amount too.

The statutory bid factor is 2.041%, derived from the formula:

Bid Factor = Tax Rate ÷ (1 − Tax Rate) = 0.02 ÷ 0.98 ≈ 2.041%

On a $500,000 contract, the difference matters:

• Adding a flat 2%: you'd charge $10,000 for tax but owe 2% of $510,000 = $10,200. You're $200 short.
• Using the 2.041% bid factor: you charge $10,205, and 2% of $510,205 = $10,204. The math closes.

The gap widens on larger contracts. On a $2 million project, the flat-2% approach leaves you roughly $816 in the hole. That's pure profit erosion from a math error that the state's own documentation addresses but many contractors overlook.

Prime Contractor vs. Subcontractor Obligations

The excise tax doesn't apply the same way to everyone on a project. The rules split based on whether the project is a standard (non-utility) contract or a utility contract:

Standard Projects (SDCL § 10-46A)

The prime contractor pays the 2% excise tax on the total contract value — including the value of all subcontracted work. To prevent double taxation, the prime issues a Prime Contractor's Exemption Certificate (DOR Form 1346) to each subcontractor for that specific project.

With a valid exemption certificate, the subcontractor is relieved of excise tax liability on their subcontracted gross receipts. However, the subcontractor still owes standard sales or use tax on materials they furnish — the exemption certificate only covers the excise tax, not the separate materials tax.

Each exemption certificate is project-specific. A blanket certificate covering multiple projects isn't valid — the prime must issue a new Form 1346 for each separate project.

Utility Projects (SDCL § 10-46B)

When the contract is directly with a qualified utility company — railroad, telephone, rural water, electric power — both the prime and all subcontractors independently owe the 2% excise tax on their respective gross receipts. Exemption certificates are prohibited in this scenario. The prime can't issue them, and subs can't accept them.

This dual-liability structure on utility projects effectively doubles the tax burden compared to standard projects. Factor it into your bids on utility work.

The Speculative Builder Trap

One of the least-expected applications of the excise tax hits people who don't think of themselves as contractors at all. Under the Department of Revenue's Speculative Builder Rule, if you buy property, build or significantly remodel a structure, and then sell it, the state classifies you as a prime contractor.

The result: the entire fair market value of the completed property becomes subject to the 2% excise tax. This applies even if you hired licensed subcontractors to do all the physical work. The tax triggers at the point of sale, creating an unexpected liability that can run into the tens of thousands on a home flip.

If you're building spec homes or buying properties for renovation and resale, this rule makes the CET license and proper tax accounting mandatory from day one — not just a contractor's obligation.

Material Tax on Top of Excise Tax

Beyond the 2% excise tax on gross receipts, contractors also owe the standard 4.5% state sales or use tax on all construction materials. If you buy materials from a South Dakota supplier, they collect sales tax at the point of purchase. If you buy from an out-of-state vendor who doesn't collect South Dakota tax, you owe 4.5% use tax on those materials.

Municipal Gross Receipts Tax (MGRT) can add another 1–2% depending on the city. This local layer varies by municipality, so materials costs differ based on where you're sourcing and where the project is located.

For owner-furnished materials (where the property owner buys their own materials), the prime contractor must include the fair market value of those materials in the taxable gross receipts for CET calculation. And the contractor is responsible for verifying that sales or use tax was paid on those materials — if the owner didn't pay, the contractor is liable for the unpaid use tax.

Filing and Compliance

CET returns are filed with the Department of Revenue on the reporting schedule assigned to your account. For each designated reporting month, remit by the 20th for a paper filing or by the 25th for an electronic filing. The returns report gross receipts from construction contracts for the period, calculate the 2% tax, and reconcile any exemption certificates issued to subcontractors.

Keeping clean records of every Form 1346 issued, every subcontractor exemption, and every material purchase with tax paid is critical for audit defense. The Department of Revenue audits construction businesses regularly, and the dual-tax structure (excise plus sales/use) creates multiple points where discrepancies can trigger an inquiry.

For the complete walkthrough of how excise tax registration fits into the broader contractor setup process — including the registration sequence, municipal licensing, and the insurance and bonding requirements that come after your CET license — see the South Dakota General Contractor License Guide.

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