Start-up tax guide

The first-year compliance checklist for a new Illinois business

A short list of what to register, file and set up, in order, with the Illinois specifics. Check things off as you go, and ask us about anything that does not fit your business.

General information for 2026. Written by Prem Tax and Accounting Corp, a CPA firm. We are not a law firm: we coordinate with your attorney for formation documents, operating agreements and stock issuance. Rules have deadlines and exceptions, and this is not tax or legal advice for your situation. Official sources are linked on each page.

Prepared by Prem Tax and Accounting Corp. Last checked against official sources on October 9, 2026.

Form the business

Choose the structure (see choosing an entity).
File Articles of Organization (LLC) or Articles of Incorporation with the Illinois Secretary of State, and appoint an Illinois registered agent.
Write an operating agreement (LLC) or bylaws (corporation) with your attorney.
Get your EIN free from the IRS.
File the elections on time (elections and deadlines).
Open a separate business bank account and card.

Register for taxes

Illinois Department of Revenue (MyTax Illinois): sales tax registration and employer withholding.
Illinois Department of Employment Security: unemployment insurance, before your first paycheck.
Federal payroll: deposit schedules, Forms 941 and 940, and W-2s. We run payroll in every state.
Local licenses and permits: city or county business license, zoning and signage, and any professional license.
Foreign qualification if you operate in another state.

Set up your money and records

A chart of accounts and bookkeeping system from day one, reconciled monthly.
Keep contracts, receipts and a mileage log. Keep tax records at least three years.
Collect a W-9 from every contractor before you pay them. Send a 1099-NEC if you pay $2,000 or more in 2026.
Plan estimated taxes (April, June, September and January), or payroll for owner pay in an S corporation.
Buy insurance and, if you have employees, workers' compensation.

A first-year timeline

When	What
Day 1	Form the entity, appoint the registered agent, get the EIN, open the bank account
Within 30 days	File the 83(b) election if you received restricted stock
Within 2 months and 15 days	File Form 2553 if you want S status from the start
Before the first sale or paycheck	Register with the Department of Revenue and Department of Employment Security
Each quarter	Payroll returns (April 30, July 31, October 31 or the next business day, January 31) and estimated tax dates
Each year	Illinois annual report, tax returns, 1099s and W-2s (January 31)

We can set all of this up for you, and keep it current. Book a 20-minute call. For the longer version of this list, see our start-up compliance checklist.

Common questions

When is the Illinois LLC annual report due?

Each year by the first day of the month your LLC was formed. The Secretary of State sends reminders, and the report is $75. A corporation files its own annual report ($75) and pays a franchise tax.

Do I have to register with the state for taxes?

Yes, depending on your business. Register with the Illinois Department of Revenue for sales tax if you sell taxable items or services and for withholding if you have employees, and with the Illinois Department of Employment Security for unemployment insurance. Do it before the first sale or paycheck.

Do I need a business license?

Many cities, counties and professions require one. Check your municipality (for example Aurora or Naperville), your industry, and any professional license.

Can I be my own registered agent?

If you are an Illinois resident with a street address in Illinois where you are available during business hours, yes. Many owners use a registered agent service so their address stays private.

Is there a federal report for new companies?

Not a beneficial ownership report for U.S. companies since August 14, 2026. You will still file the tax returns for your entity, payroll returns if you have employees, and information returns for contractors you pay $2,000 or more in 2026.

Official sources

Starting a business? We help you choose the structure, file the elections on time, set up payroll and books, and plan the first-year taxes so there are no surprises. Book a 20-minute call or send us a message.

Let's talk about your taxes, your business, your plans.

Tell us what you need and we will get back to you quickly. There is no pressure: just a friendly conversation and a clear next step.

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Prem Tax and Accounting Corp
4260 Westbrook Dr, Suite 107
Aurora, IL 60504

Monday to Friday, 9:00 am to 5:00 pm, by appointment. Saturday and Sunday by appointment when needed.