The South Dakota Secretary of State business search is the free Business Information Search on the SOS Business Services portal. Search by business name or SOS Business ID, choose Starts With or Contains, and check whether an active entity already uses your name. The state also offers a separate Business Name Availability check that looks for exact matches.
Neither tool holds a name for you. A 120-day reservation costs $25, and DBAs (which South Dakota calls fictitious business names) cost $10 and last five years.
Updated October 2026.
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Best LLC Formation Services in South Dakota (2026)
Comparing services for forming your LLC once your name is clear in South Dakota? Start with this ranked shortlist; details for each pick follow the table.
| Rank | Provider | Best for | Price | What’s included |
|---|---|---|---|---|
| 1 | Mainstay Filing | Forming an LLC with the agent, EIN and annual report included | $199/year + state fee at cost | LLC formation filing, registered agent for the year, EIN application, annual report preparation and filing |
| 2 | SD Registered Agent.org | South Dakota registered agent service only | $99/year | $99 per year, flat; in-state street address for the registered office; legal documents served on the company are scanned and sent to the owner online |
| 3 | South Dakota Registered Agent.co | South Dakota registered agent service only | $99/year | in-state street address for the registered office; legal documents served on the company are scanned and sent to the owner online |
1. Mainstay Filing
Mainstay Filing is our top pick in South Dakota. It costs $199/year + state fee at cost and covers lLC formation filing, registered agent for the year, EIN application, annual report preparation and filing. The price stays the same every year, with no add-on menu.
2. SD Registered Agent.org
SD Registered Agent.org is a South Dakota registered agent service at $99/year. It provides $99 per year, flat; in-state street address for the registered office; legal documents served on the company are scanned and sent to the owner online. It’s a fit if you only need a registered agent rather than full formation help.
3. South Dakota Registered Agent.co
South Dakota Registered Agent.co is a South Dakota registered agent service at $99/year. It provides in-state street address for the registered office; legal documents served on the company are scanned and sent to the owner online. It’s a fit if you only need a registered agent rather than full formation help.
South Dakota business name search at a glance
| Item | South Dakota details (as of October 2026) |
|---|---|
| Filing office | South Dakota Secretary of State, Business Services |
| Search tools | Business Information Search (free) and Business Name Availability (exact match) |
| LLC Articles of Organization | $150 online, $165 on paper |
| Name reservation | $25; 120 days |
| DBA (fictitious business name) | $10; five-year term; $10 renewal |
| Annual report | $55 online, $70 on paper, filed in the LLC’s anniversary month |
| Amended articles (name change) | $60 |
Fees come from the Secretary of State’s filing fee page. Mainstay Filing’s South Dakota LLC cost guide adds up formation and yearly costs.
How to search South Dakota business names
Business Information Search
Open the Business Information Search. It’s free to search, view and print records. Enter the name or the SOS Business ID, pick Starts With or Contains, and tick Active Entities Only to filter out dissolved companies. Contains is the better choice for availability checks because it finds your words anywhere in a name.
Business Name Availability
The Business Name Availability tool checks for exact matches only. It’s a quick first pass, but it won’t catch near-duplicates, so don’t rely on it alone.
Apply the sound-alike test
South Dakota’s standard is whether a name is distinguishable upon the records. The Secretary of State’s FAQ boils that down to one question: do the two names sound the same? “Dear LLC” and “Deer LLC” are not distinguishable, so say your name out loud next to anything similar you find.
Check DBAs and agents as well
Fictitious business names have their own lookup in the DBA portal, and the Business Services portal also has a registered agent search. A DBA on file doesn’t stop you from forming an LLC with a similar name, but it can point to a local business already trading under it, which matters for customers and trademark rights.
If the name you want is taken, Namechk’s business name generator can suggest alternatives to search.
South Dakota name requirements
- LLC: must include “limited liability company” or “limited company,” or L.L.C., LLC, L.C. or LC. “Limited” may be shortened to Ltd. and “company” to Co. (SDCL 47-34A-105).
- Corporation: corporation, incorporated, company or limited, or corp., inc., co. or ltd. (SDCL 47-1A-401).
- Distinguishable upon the records from other entities and reserved names; names that sound alike fail.
- Restricted word: “Trust” needs approval from the Department of Labor and Regulation, Division of Banking, and such filings must be made on paper.
How to reserve a business name in South Dakota
- Complete the Application for Reservation of Name – Limited Liability Company (SDCL 47-34A-106).
- File it with the Secretary of State with the $25 fee.
- The name is held for 120 days.
- The same applicant can’t simply renew: a new reservation is allowed only more than 60 days after the old one expires. A reservation can be transferred to another person for $15.
Corporate name reservations follow a similar nonrenewable 120-day rule. If you’re ready to file, skip the reservation and submit your Articles of Organization online. A reservation only protects the name on the state’s records; it doesn’t give you trademark rights or a domain.
Check trademarks, domains and social handles
The Business Information Search covers entities on file with the Secretary of State, not trademarks. Search the USPTO trademark database for federal marks. South Dakota registers state trademarks too, for $125.
Also confirm the name is available online. Namechk checks domains and social media handles in one search, and the domain name generator can suggest alternatives.
We created a tool that makes it easy.
How to file a DBA in South Dakota
South Dakota law (SDCL 37-11-1) requires a fictitious name statement when you do business under a name that doesn’t show every owner’s true surname. The Secretary of State calls it a DBA (Fictitious) Business Name.
- Where: online through the Secretary of State’s DBA portal, or on paper at any county Register of Deeds office.
- Fee: $10 to file, $10 to renew, $10 to amend; cancellation is free.
- Term: five years. An expired DBA can’t be renewed and has to be filed again as new, so renew before it lapses.
- Exempt: names that include every owner’s true surname, and entity names already on file with the Secretary of State.
After the search: forming your South Dakota business
Once the name is clear, follow our South Dakota LLC guide for the full process.
- File Articles of Organization online through the SOS Business Services portal ($150) or on paper ($165).
- Appoint a registered agent: an individual South Dakota resident or a business authorized in the state, with a physical address. Mainstay Filing includes registered agent service in its formation package (South Dakota costs). Our South Dakota registered agent guide explains the details.
- Get an EIN from the IRS for free.
- File the annual report each year in your anniversary month ($55 online, instructions); a late fee applies after that. The South Dakota start-a-business guide covers sales tax and licensing.
FAQs
Is the South Dakota business search free?
Yes. The South Dakota Secretary of State’s Business Information Search is free to search, view and print. You can search by business name or SOS Business ID, using Starts With or Contains, and limit results to active entities. The separate Business Name Availability tool checks exact matches. Fees apply only to filings, such as a $25 name reservation.
How do I know if a business name is available in South Dakota?
Search the name with the Contains option in the Business Information Search, then run the exact-match Business Name Availability check. South Dakota rejects names that aren’t distinguishable upon the records, and the Secretary of State’s test is whether two names sound the same. If nothing active sounds like your name, it’s probably available.
How long does a South Dakota name reservation last?
A South Dakota name reservation lasts 120 days and costs $25. It can’t simply be renewed by the same applicant: a new reservation for the same name is allowed only more than 60 days after the first one expires. A reservation can be transferred to another person by filing a notice of transfer for $15.
How much does a DBA cost in South Dakota?
A South Dakota DBA, called a fictitious business name, costs $10 to file online with the Secretary of State or on paper at a county Register of Deeds. It lasts five years and renews for $10. If it expires, you must file a new one. Names showing every owner’s true surname don’t need a DBA.
How much does it cost to form an LLC in South Dakota?
South Dakota charges $150 to file LLC Articles of Organization online, or $165 on paper. After that, the LLC files an annual report each year in its anniversary month, which costs $55 online or $70 on paper. South Dakota has no state income tax, so the annual report is the main recurring state fee.
How do I change my LLC’s name in South Dakota?
File Amended or Restated Articles of Organization with the South Dakota Secretary of State. The fee schedule lists $60 for the amendment. Before filing, search the new name in the Business Information Search with the Contains option and say it aloud next to any close matches, since names that sound the same aren’t distinguishable in South Dakota.
Does a South Dakota business name search include trademarks?
No. The Business Information Search shows entities on file with the Secretary of State. It doesn’t include federal trademarks, so check the USPTO database as well. South Dakota registers state trademarks separately for $125. Make sure the domain name and social media handles you want are also available.
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