Check our 2025 Tax Deadlines For C-Corp Startups or Click for your customized tax compliance calendar by startup hub
Startup companies based in Chicago have several important tax deadlines in 2025, including the April 15th federal and Illinois tax return filings (which can be extended until October 15th). Additionally, Illinois and the federal government have various tax filings due on the dates listed below.
Quarterly Payroll Withholding Report due for Illinois – Quarter 1.
Chicago startups can claim Research & Development Tax Credits on Form 941.
Delaware Quarterly Estimated Franchise Tax. Pay 40% of estimated annual amount (if annual amount expected to exceed $5,000).
Quarterly Payroll Withholding Report due for Illinois – Quarter 2.
Claim Research & Development Tax Credits on Form 941 .
Delaware Quarterly Estimated Franchise Tax. Pay 20% of your estimated annual amount (if annual amount expected to exceed $5,000).
Extended due date for Illinois Corporate Income Tax Return.
Federal Quarterly Estimated Tax 3rd installment (third quarter 2024).
Quarterly Payroll Withholding Report due for Illinois – Quarter 3.
Claim your Research & Development Tax Credits on Form 941.
Delaware Quarterly Estimated Franchise Tax, Pay 20% of estimated annual amount (if annual amount expected to exceed $5,000).
Click The Links To Learn More About These Filings And 2025 Chicago Startup Tax Deadlines
Quarterly Payroll Withholding Report due for Illinois – Quarter 4.
Claim Research & Development Tax Credits on Form 941, and file annual Federal Unemployment Tax Act (FUTA) return on Form 940. Use our handy calculator to estimate your possible research and development tax credit.
Delaware Annual Franchise Report filing deadline. Your Chicago startup will pay a minimum of $400, which increases if you have significant funding.
IRS 30-day automatic extension: provide Form 1095-B and Form 1095C to employees.
Due date for Illinois Corporate Income Tax Return (can be extended to September 15).
C Corp Form 1120 Tax Return due. The Federal Form 1120 is the U.S. Corporation Income Tax Return, which the IRS has companies use to report their income, losses, credits, etc., and to figure the income tax liability of the corporation. Can extend the deadline to Oct. 15. All Chicago startups are required to file this Federal form by this deadline unless they file an extension.
Federal Quarterly Estimated Tax 1st installment (first quarter 2024).
File the R&D Tax Credit Form 6765 with your tax return. Can extend to October 15. We strongly recommend working with a qualified CPA to prepare this form in conjunction with your Form 1120 if you are a high-growth startup – if your company is going to be acquired by a major technology company, that company’s CFO will use a strong tax team to do due diligence on this.
Due date for Chicago startup employees to make contributions to Individual Retirement Accounts (IRAs) for 2023 (Employee Benefits).
Quarterly Payroll Withholding Report due for Illinois – Quarter 1.
Chicago startups can claim Research & Development Tax Credits on Form 941.
Delaware Quarterly Estimated Franchise Tax. Pay 40% of estimated annual amount (if annual amount expected to exceed $5,000).
Federal Quarterly Estimated Tax 2nd installment (second quarter 2024).
Quarterly Payroll Withholding Report due for Illinois – Quarter 2.
Claim Research & Development Tax Credits on Form 941 .
Delaware Quarterly Estimated Franchise Tax. Pay 20% of your estimated annual amount (if annual amount expected to exceed $5,000).
Extended due date for Illinois Corporate Income Tax Return.
Federal Quarterly Estimated Tax 3rd installment (third quarter 2024).
C Corp Form 1120 Tax Return final due date for Chicago startups if extension was filed.
Quarterly Payroll Withholding Report due for Illinois – Quarter 3.
Claim your Research & Development Tax Credits on Form 941.
Delaware Quarterly Estimated Franchise Tax, Pay 20% of estimated annual amount (if annual amount expected to exceed $5,000).
Federal Quarterly Estimated Tax 4th installment (fourth quarter 2024).
Note: The federal tax deadline in 2025 falls on April 15. The federal extension deadline for 2025 is October 15. Most states usually follow the same calendar for state income tax returns
If your Delaware C-Corp Chicago funded startup needs tax help contact us today!
CHICAGO, STARTUPS AND TAXES
In 2023, Chicago startups raised significant funding, including over $873 million in December 2023 alone. Among startup ecosystems in 2024, Chicago was ranked 6th in the United States and 15th globally by the Global Startup Ecosystem Index. As a major center for business and commerce, Chicago offers startups a wide customer base of Fortune 500 and Fortune 1000 companies. The business culture is also diverse – Inc. reports that no single sector drives more than 14% of the local economy,
The most important taxing authorities for companies based in Boston are:
In 2025, Chicago-based companies have several important tax deadlines, including the April 15th federal and Illinois tax return filings (which can be extended until October 15th). Additionally, Illinois and the federal government have various tax filings due on the dates listed above.
2024 startup tax deadlines are supplied for reference purposes only, and should not be used when making decisions in 2025 or beyond. Always consult your tax professional, and see our disclaimer below.
Click The Links To Learn More About These Filings And 2024 Chicago Startup Tax Deadlines
Federal Quarterly Estimated Tax 4th installment (fourth quarter 2023).
Quarterly Payroll Withholding Report due for Illinois – Quarter 4.
Chicago startups should send 1099s to contractors. Send W2s to employees and e-file 1099-MISC for non-employee compensation with the IRS. Or file Form 8809 for a 30-day extension to file W2s and 1099-MISC for non-employee compensation.
Claim Research & Development Tax Credits on Form 941, and file annual Federal Unemployment Tax Act (FUTA) return on Form 940. Use our handy calculator to estimate your possible research and development tax credit.
IRS 30-day automatic extension: provide Form 1095-B and Form 1095C to employees.
Delaware Annual Franchise Report filing deadline. Your Chicago startup will pay a minimum of $400, which increases if you have significant funding.
Due date for Illinois Corporate Income Tax Return (can be extended to September 15).
Due date for Chicago startup employees to make contributions to Individual Retirement Accounts (IRAs) for 2023 (Employee Benefits).
File the R&D Tax Credit Form 6765 with your tax return. Can extend to October 15. We strongly recommend working with a qualified CPA to prepare this form in conjunction with your Form 1120 if you are a high-growth startup – if your company is going to be acquired by a major technology company, that company’s CFO will use a strong tax team to do due diligence on this.
Federal Quarterly Estimated Tax 1st installment (first quarter 2024).
C Corp Form 1120 Tax Return due. The Federal Form 1120 is the U.S. Corporation Income Tax Return, which the IRS has companies use to report their income, losses, credits, etc., and to figure the income tax liability of the corporation. Can extend the deadline to Oct. 15. All Chicago startups are required to file this Federal form by this deadline unless they file an extension.
Chicago startups can claim Research & Development Tax Credits on Form 941.
Quarterly Payroll Withholding Report due for Illinois – Quarter 1.
Delaware Quarterly Estimated Franchise Tax. Pay 40% of estimated annual amount (if annual amount expected to exceed $5,000).
Federal Quarterly Estimated Tax 2nd installment (second quarter 2024).
Quarterly Payroll Withholding Report due for Illinois – Quarter 2.
Claim Research & Development Tax Credits on Form 941 .
Delaware Quarterly Estimated Franchise Tax. Pay 20% of your estimated annual amount (if annual amount expected to exceed $5,000).
Extended due date for Illinois Corporate Income Tax Return.
Federal Quarterly Estimated Tax 3rd installment (third quarter 2024).
C Corp Form 1120 Tax Return final due date for Chicago startups if extension was filed.
Quarterly Payroll Withholding Report due for Illinois – Quarter 3.
Claim your Research & Development Tax Credits on Form 941.
Delaware Quarterly Estimated Franchise Tax, Pay 20% of estimated annual amount (if annual amount expected to exceed $5,000).
View tax compliance dates for Austin, Boston, New York City, Palo Alto, San Francisco, Santa Monica, Seattle, Washington DC, Atlanta, Salt Lake City, Mountain View, Chicago, Dallas, Miami, and San Jose
How Much Does a Startup Tax Return Cost? Try Kruze Consulting's Tax Preparation Pricing Tool.
How much can your startup save in payroll taxes? Estimate your R&D tax credit using our free calculator.
Every startup is different and so are its tax compliance needs. This is only a guideline. Please consult your tax professional. IRS Circular 230 Disclaimer: To ensure compliance with IRS Circular 230, any U.S. federal tax advice provided in this communication is not intended or written to be used, and it cannot be used by the recipient or any other taxpayer for the purpose of avoiding tax penalties that may be imposed on the recipient or any other taxpayer. Copyright © Kruze Consulting
Check our 2025 Tax Deadlines For C-Corp Startups or Click for your customized tax compliance calendar by startup hub
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