Michigan Form 518 is the state’s business tax registration application, and you can file it two ways: electronically through Michigan Treasury Online (MTO), which processes in about 48 hours, or on paper by mail to the Department of Treasury in Lansing, which takes three to four weeks.1Michigan Department of Treasury. New Business Registration There is no fee. One application opens accounts for sales tax, use tax, income tax withholding, corporate income tax, and unemployment insurance tax — you check a box for each one that applies to your business.2Michigan Department of Treasury. Michigan Business Taxes Registration Booklet
Which Tax Accounts Form 518 Opens
Before you start filling anything in, know which boxes you’ll be checking. Each tax has its own trigger.
Sales tax. If you sell tangible personal property to end consumers in Michigan, you must have a sales tax license before your first sale.3Michigan Legislature. Michigan Compiled Laws 205.53 – License Required to Engage in Business for Which Privilege Tax Imposed You’ll collect the state’s 6% sales tax and remit it on a schedule Treasury assigns after you register.4Michigan Department of Treasury. Sales and Use Taxes The license itself is free.5Michigan Department of Treasury. Sales Tax License FAQ
Use tax. If you buy equipment or supplies from out-of-state vendors who don’t collect Michigan sales tax, you owe 6% use tax on those purchases and self-report through your Treasury account.6Michigan Legislature. Michigan Compiled Laws 205.93 – Use Tax Act
Income tax withholding. Every Michigan employer required to withhold federal income tax must also withhold state income tax from employee pay.7Michigan Department of Treasury. 2026 Michigan Income Tax Withholding Guide Your filing frequency (monthly, quarterly, or annually) is assigned based on estimated liability.
Corporate income tax (CIT). C-corporations and insurance companies with nexus in Michigan register through Form 518. Under MCL 206.621, you have nexus if you maintain a physical presence in the state for more than one day during the tax year, or if you actively solicit sales and have gross receipts of $350,000 or more sourced to Michigan.8Michigan Legislature. Michigan Compiled Laws 206.621 – Nexus, Actively Solicits and Physical Presence Defined Below $350,000 in allocated or apportioned gross receipts, no CIT filing is required.9Michigan Department of Treasury. Corporate Income Tax
Unemployment insurance. Form 518 starts the unemployment registration, but that tax is administered by the Unemployment Insurance Agency, not Treasury. The UIA will separately issue your unemployment account number after you submit.10Michigan Department of Labor and Economic Opportunity. Register Your Business
If you’re an out-of-state seller with no physical presence in Michigan, sales tax nexus kicks in when your prior-year sales into the state exceeded $100,000 or 200 separate transactions.11Michigan Department of Treasury. Remote Seller FAQ That threshold is separate from the $350,000 CIT standard, so a remote seller can owe sales tax without owing CIT and vice versa.
What to Have Ready Before You Open the Form
Gather everything before you start. The online application won’t let you save partway through, and a missing field will send you back to the beginning.
- FEIN. Your federal Employer Identification Number from the IRS. Sole proprietors with no employees can use a Social Security Number instead. If you’ve applied for a FEIN but haven’t received it, you must use the paper form — the online system requires one.1Michigan Department of Treasury. New Business Registration
- Legal business name and DBA. Partnerships and corporations include the entity indicator (LLC, Corp, Inc.) on Line 2. Sole proprietors put their personal name on Line 2 and the business name on Line 3.2Michigan Department of Treasury. Michigan Business Taxes Registration Booklet
- Three addresses. A legal address where books and records are kept (Line 4), a mailing address for correspondence, which can be a P.O. Box (Line 5), and the Michigan physical location if it differs from the legal address (Line 6).
- NAICS code. The six-digit industry classification. Look yours up on the Census Bureau’s NAICS site before starting; this field is mandatory.
- LARA Corporate ID Number. Only if you formed your entity through Michigan’s Department of Licensing and Regulatory Affairs. Out-of-state entities won’t have one.
- Owner and officer details. Full legal name, home address, and Social Security Number for every owner, partner, or corporate officer. Treasury uses this to establish personal accountability for the business’s tax obligations.
- Estimated tax liability. Your best estimate of monthly or annual sales tax and withholding. This is what Treasury uses to assign your filing frequency.
- Business start date. The exact date taxable activity begins. This determines the first return period.
Filling In the Sections That Trip People Up
The booklet says “lines not listed are explained on the form,” and most fields really are that simple. A few need attention.
At the top, the “Reason for This Application” section asks why you’re filing. Straightforward for a new business. If more than one reason applies and a third party handles part of your withholding — for example, a payroll service running employee payroll while you handle pension withholding on retirees — file two separate Form 518s, one for each function, so Treasury knows which party is responsible for which account.2Michigan Department of Treasury. Michigan Business Taxes Registration Booklet
Line 7 asks for a business ownership type code. The booklet lists codes from 10 to 90 for corporations, LLCs, partnerships, sole proprietorships, trusts, and other structures. Match the code to your actual legal structure, not what you informally call the business. Getting this wrong triggers the wrong tax forms and filing requirements.
Lines 10 and 11 ask you to describe your business activity and the products you sell. Keep it short but specific. “Retail clothing store” is better than “retail” and helps Treasury classify your account correctly.
Lines 12 through 15 are where you check each tax type and enter the date liability begins for each. The dates don’t have to match across taxes. If you’re registering for sales tax now and your first payroll runs a month later, enter each date on its own line.
Filing Online Through Michigan Treasury Online
Go to mto.treasury.michigan.gov and create a personal MiLogin profile if you don’t already have one. From the MTO homepage, click “Start a New Business (E-Registration).” The application opens in a new tab.1Michigan Department of Treasury. New Business Registration
Your FEIN becomes your Treasury business account number. The system recognizes your submission within about 15 minutes, and full processing takes up to 48 hours. To check status, log back in and try to connect your user profile to the business account through the “Manage Business Registration” service. If you can move past entering your account number, processing is complete. If you hit an error, give it more time.
Print or save the completed application before you submit. Retrieving a copy afterward isn’t always easy.
Filing on Paper by Mail
Use the paper booklet if you don’t have a FEIN yet or the online system is down. Download Form 518 from the Department of Treasury website, complete it in dark ink with original signatures, and mail to:
Michigan Department of Treasury
Registration Section
P.O. Box 30778
Lansing, MI 4890912Michigan Department of Treasury. Notice of Change or Discontinuance
Allow 7 to 10 days for the mail plus about two weeks for processing — roughly three to four weeks total.1Michigan Department of Treasury. New Business Registration A February 2026 MTO portal notice asked filers to allow four weeks for mailed applications during busy periods.13Michigan Treasury Online. Welcome to Michigan Treasury Online Once processed, Treasury assigns your account number and mails personalized sales, use, and withholding returns to the address you gave.
After Registration: Updates, Closures, and Buying an Existing Business
Log into MTO to make routine changes like updating an address. For significant changes such as converting from a sole proprietorship to an LLC, you may need to file a new Form 518 for the new entity.12Michigan Department of Treasury. Notice of Change or Discontinuance
To close your business, file Form 163 (Notice of Change or Discontinuance) through MTO or mail the signed paper version to the same P.O. Box 30778 address. File all final returns for the year of closure. If you’re closing on behalf of a deceased owner, include a copy of the death certificate.
Buying an existing Michigan business is a separate concern. Under successor liability, Treasury can assess a buyer for the prior owner’s unpaid taxes, interest, and penalties, even liabilities the buyer didn’t know about. If you’re acquiring only some of the assets, exposure is capped at the fair market value of what you bought, but the liability still attaches. Protect yourself by escrowing enough to cover outstanding tax obligations until the state confirms payment, or by obtaining a tax clearance certificate from Treasury before closing. Build either approach into the purchase agreement. You still need to file your own Form 518 — the previous owner’s registration does not transfer.
What Form 518 Doesn’t Cover
Some Michigan tax licenses have their own separate registration processes. Motor fuel licenses, International Fuel Tax Agreement (IFTA) licenses, and tobacco product licenses each go through their own contacts at Treasury.2Michigan Department of Treasury. Michigan Business Taxes Registration Booklet If your business involves fuel distribution, interstate trucking, or tobacco sales, call the numbers in the Form 518 booklet for the correct application for each.