Business Tax Returns in a State With No Corporate Income Tax
South Dakota does not tax the general income of corporations, LLCs or partnerships, and it has no individual income tax for owners. That makes the state attractive, but it does not make tax season go away. A South Dakota company still files a full federal return every year, often owes returns in neighbouring states, and reports to the Department of Revenue on a schedule that runs all year. BOMCAS prepares the federal business return and makes sure it agrees with everything else the business has already told the state.
What a South Dakota Business Still Files
For a typical operating company, the annual and recurring filings look like this:
- A federal income tax return: Form 1120 for a C corporation, Form 1120-S for an S corporation, Form 1065 for a partnership or multi-member LLC, or Schedule C on the owner's Form 1040 for a sole proprietor or single-member LLC.
- South Dakota sales and use tax returns, and contractor's excise tax returns for prime contractors, filed every assigned period even when nothing was sold.
- Quarterly reemployment assistance wage reports to the Department of Labor and Regulation if the business has employees.
- An annual report to the South Dakota Secretary of State, due each year in the anniversary month of the entity's formation. A report filed late enough to become delinquent carries an extra late fee.
- Income tax returns in other states where the business has income or activity, and federal information returns such as Forms 1099 and W-2.
Choosing and Preparing the Right Federal Return
S corporations and partnerships
Pass-through returns for calendar-year businesses are due March 15, and the income flows to the owners' personal returns through Schedules K-1. Because the owners pay no South Dakota income tax, the federal K-1 is usually the main document they need, so we deliver it early enough for their own returns to be filed without extensions where possible.
C corporations
Calendar-year C corporation returns are due April 15. C corporations in South Dakota pay federal corporate tax only, unless they have income in another state that taxes corporations. We review retained earnings, dividends and shareholder loans each year, since those items tend to draw IRS questions.
Sole proprietors and single-member LLCs
Schedule C and self-employment tax are prepared with the owner's personal return. We separate business and personal spending in the books before the return is drafted, so deductions are supported. Federal extensions are available on Form 7004 for business returns, but an extension gives more time to file, not more time to pay.
Neighbouring States Can Still Tax You
South Dakota borders six states. Minnesota, Iowa, Nebraska, North Dakota and Montana all have income taxes, and only Wyoming does not. A Sioux Falls company with customers or crews across the Minnesota and Iowa lines, a North Sioux City business serving Sioux City, or a Rapid City firm working jobs in Montana can create income tax filing obligations in those states. When that happens, the pass-through owners may also owe nonresident returns there. We review where work is performed, where property and employees sit, and where sales are delivered, and we prepare the out-of-state returns that follow.
Federal Changes That Affect Recent Returns
The 2025 federal tax legislation changed several items that matter to South Dakota businesses, especially capital-heavy ones such as farms, ranches, contractors and trucking companies:
- A permanent 100 percent additional first-year (bonus) depreciation deduction for qualified property acquired after January 19, 2025.
- A Section 179 expensing limit of $2,500,000 for property placed in service in tax years beginning after December 31, 2024, reduced once total qualifying purchases exceed $4,000,000, with inflation indexing after 2025.
- A higher reporting threshold for payment platforms, which generally report and back-up withhold only when a payee exceeds both $20,000 and 200 transactions in a year.
Taking the largest deduction in one year is not always best. We compare full expensing against regular depreciation, especially when income is uneven or losses would go unused.
Reconciling State Filings to the Federal Return
Because South Dakota relies on sales and excise taxes, gross receipts reported to the Department of Revenue should line up with revenue on the federal return. Sales tax that a business collects and remits is not its income, but contractor's excise tax is calculated on gross receipts that include tax collected from the customer. Those differences need to be explained in the books. Each year we tie the state returns filed during the year to federal revenue, so a mismatch is found and explained before an auditor finds it.
Industries We Often Prepare Returns For
- Agriculture: farm returns on Schedule F or entity returns, crop and livestock inventory, and machinery depreciation. Farm machinery used exclusively for agriculture carries South Dakota's farm machinery excise tax rather than regular sales tax, and the purchaser owes it if the retailer does not charge it.
- Construction: percentage-of-completion or completed-contract methods for federal purposes, with contractor's excise tax tracked by project.
- Tourism and hospitality: seasonal revenue in the Black Hills, along with tourism tax and municipal gross receipts tax that must be separated from income.
- Remote and online sellers: businesses registered in South Dakota because they sell more than $100,000 into the state each year.
How a Business Tax Engagement Works
We start with last year's federal return, the year-end trial balance, fixed-asset purchases and sales, and the state returns filed during the year. We send a short list of questions, prepare the return and supporting schedules, and walk the owner through the result before anything is filed. Everything is handled remotely, so location within South Dakota does not matter, whether the business is in Sioux Falls, Rapid City, Aberdeen, Brookings or on a ranch west of the river.
South Dakota Business Tax Preparation Questions
Does a South Dakota LLC file a state income tax return?
No. South Dakota has no general corporate or individual income tax, so an LLC does not file a South Dakota income tax return. It still files a federal return, any required sales or excise tax returns, and an annual report with the Secretary of State.
When are federal business returns due?
For calendar-year businesses, S corporation and partnership returns are generally due March 15 and C corporation returns are generally due April 15. Form 7004 extends the time to file, but not the time to pay.
Can my South Dakota business owe tax in Minnesota or Iowa?
Yes. Minnesota, Iowa, Nebraska, North Dakota and Montana tax business income. Work, employees, property or sales in those states can create a filing requirement there, and pass-through owners may owe nonresident returns.
Should I take 100 percent bonus depreciation on new equipment?
Not always. Qualified property acquired after January 19, 2025 can be fully expensed, but spreading deductions can be better when income varies or a loss would go unused. We compare both before the return is filed.
Talk to BOMCAS About Business Tax Preparation in South Dakota
A business return is only as good as the records behind it, so most clients pair it with monthly bookkeeping and, once they have staff, payroll. Owners usually have their personal returns prepared at the same time, and we look at the year ahead through tax planning. Sellers should confirm their sales and use tax filings are current before the return is finished, companies with years to catch up can start with back taxes and late filing, and Canadian owners will find the treaty side under cross-border tax. For a summary of how South Dakota taxes businesses and residents, see the South Dakota accounting and tax overview or our United States services.
Tell us what you need help with and we will reply with next steps. Contact BOMCAS, use the contact form below, call 780-667-5250 or email info@bomcas.ca. You can also go back to the South Dakota overview. This page is general information, not advice for a particular situation.