A Delaware corporation, LLC, or partnership owes the IRS exactly what any other U.S. entity owes: federal tax obligations for a Delaware entity cover classification, an Employer Identification Number, an annual return matched to that classification, estimated tax payments during the year, and employment tax filings if you pay wages. Delaware’s state-level advantages don’t change any of this.
How the IRS Classifies Your Delaware Entity
Classification controls everything that follows, so start there. A Delaware corporation (any entity formed under a statute that uses “corporation” or “incorporated”) is automatically a C-Corporation taxed at the entity level at a flat 21% federal rate.1Internal Revenue Service. Overview of Entity Classification Regulations
A Delaware LLC gets a flexible default. One member means the IRS treats the LLC as a “disregarded entity” and the owner reports everything on a personal return. Two or more members means partnership treatment, with the entity filing an information return and the owners paying tax individually.1Internal Revenue Service. Overview of Entity Classification Regulations
Changing the Default
You can override the default. An LLC that wants C-Corp treatment, or a multi-member LLC that wants to be disregarded, files Form 8832 (Entity Classification Election).2Internal Revenue Service. About Form 8832, Entity Classification Election The election can take effect up to 75 days before or 12 months after the filing date.
Electing S-Corporation Status
An LLC or corporation that wants pass-through income with less self-employment tax exposure files Form 2553 to elect S-Corporation status.3Internal Revenue Service. Instructions for Form 2553 An LLC must first be classified as a corporation (by default or by filing Form 8832) before making the S election.
Not every entity qualifies. To be a “small business corporation” under the Internal Revenue Code, the entity must be domestic, have no more than 100 shareholders (family members can count as one), limit shareholders to individuals and certain trusts and tax-exempt organizations, exclude nonresident aliens, and maintain only one class of stock.4Office of the Law Revision Counsel. 26 U.S. Code 1361 – S Corporation Defined Differences in voting rights alone don’t create a second class, and straight debt is safe. Miss any of these and the IRS will reject or revoke the election.
Getting an Employer Identification Number
Almost every Delaware entity needs an EIN before it can open a bank account, file a return, or hire. Corporations and partnerships must have one. A single-member LLC with no employees and no excise tax liability isn’t technically required to have one, but banks and vendors usually ask for it anyway.5Internal Revenue Service. About Form SS-4, Application for Employer Identification Number
You apply using Form SS-4. The form requires a “responsible party,” which the IRS defines as the natural person who controls the entity’s funds and assets. That person must provide a Social Security Number or Individual Taxpayer Identification Number.6Internal Revenue Service. Instructions for Form SS-4 Applicants with a valid SSN or ITIN can apply online and receive the EIN immediately. Those without either number must submit the form by fax or mail, which takes several weeks.
Which Annual Return You File
Your classification determines the return, the due date, and whether the entity pays tax or just reports.
C-Corporation: Form 1120
A C-Corporation files Form 1120 to report income, deductions, and credits and to pay the 21% corporate tax.7Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return Calendar-year filers are due April 15.8Internal Revenue Service. Publication 509 (2026), Tax Calendars
S-Corporation: Form 1120-S
An S-Corporation files Form 1120-S, an information return; the entity itself owes no federal income tax.9Internal Revenue Service. About Form 1120-S, U.S. Income Tax Return for an S Corporation Calendar-year deadline: March 15. The entity issues a Schedule K-1 to each shareholder reporting their share of income, deductions, and credits, and shareholders report those amounts on their personal returns.8Internal Revenue Service. Publication 509 (2026), Tax Calendars
Partnership (Multi-Member LLC): Form 1065
A multi-member LLC taxed as a partnership files Form 1065 by March 15 for calendar-year entities.10Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income The partnership pays no income tax but must issue a Schedule K-1 to each partner.
Disregarded Entity: Schedule C or E
A single-member LLC classified as disregarded files nothing separate. The owner reports business income and expenses on Form 1040. Active trade or business income goes on Schedule C.11Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business Rental real estate goes on Schedule E.12Internal Revenue Service. About Schedule E (Form 1040), Supplemental Income and Loss
Net Schedule C earnings are also subject to the 15.3% self-employment tax (12.4% Social Security and 2.9% Medicare), reported on Schedule SE.13Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
Estimated Tax Payments During the Year
Filing the annual return is only half of it. C-Corporations expecting to owe $500 or more must make quarterly estimated payments due on the 15th day of the 4th, 6th, 9th, and 12th months of the tax year. For calendar-year corporations, that’s April 15, June 15, September 15, and December 15. Underpaying triggers a separate penalty calculated on each quarter’s shortfall.14Internal Revenue Service. Underpayment of Estimated Tax by Corporations Penalty
Pass-through owners (S-Corp shareholders, partners, single-member LLC owners) don’t pay estimates through the entity. They make personal estimated payments on Form 1040-ES if they expect to owe $1,000 or more. First-year owners routinely underestimate this because no employer is withholding from their distributions.
Employment Taxes If You Have Employees
Paying wages adds a separate layer that applies regardless of classification. Employers must withhold federal income tax, Social Security, and Medicare from employee wages and report quarterly on Form 941. The employer also pays its own share of Social Security and Medicare. On top of that, the entity files Form 940 for federal unemployment tax, which the employer pays entirely.15Internal Revenue Service. Depositing and Reporting Employment Taxes
By January 31 each year, you must give every employee a Form W-2 and file copies with the Social Security Administration. Employers filing 10 or more information returns must file them electronically.15Internal Revenue Service. Depositing and Reporting Employment Taxes Payroll tax deposits themselves follow their own schedule, monthly or semi-weekly depending on your deposit history, and late deposits carry their own penalties.
Form 5472 for Foreign-Owned LLCs
A Delaware single-member LLC wholly owned by a foreign person (individual, corporation, partnership, or trust) is treated as a corporation for one narrow purpose: Form 5472 reporting. The LLC must file a pro forma Form 1120 with Form 5472 attached, even though it has no income tax liability as a disregarded entity.16Internal Revenue Service. Instructions for Form 5472
There is no minimum income threshold. An LLC with zero revenue must still file if it had any reportable transaction with its foreign owner or a foreign related party, which can be as simple as a capital contribution. The penalty for failing to file is $25,000 per form, per year, and the IRS has been aggressive about assessing it.
What Late Filing Costs
Penalty structures vary sharply by entity type, and this is where Delaware LLC owners get hit hardest.
Partnerships and S-Corporations
Penalties here are calculated per owner, per month. The base statutory amount is $195 per partner or shareholder for each month or partial month the return is late, up to 12 months.17Office of the Law Revision Counsel. 26 USC 6698 – Failure to File Partnership Return18Office of the Law Revision Counsel. 26 U.S. Code 6699 – Failure to File S Corporation Return That amount is adjusted annually for inflation; for returns required to be filed in 2026, the figure is $260 per owner per month.
The math adds up fast. A four-member LLC six months late on its partnership return owes $6,240 ($260 × 4 partners × 6 months). A ten-shareholder S-Corp that misses by one day owes $2,600 for the partial first month. The IRS can abate for reasonable cause, but “I didn’t know I had to file” rarely qualifies.
C-Corporations
C-Corp penalties are different. The failure-to-file penalty is 5% of the unpaid tax for each month or partial month the return is late, capped at 25% of the tax due.19Internal Revenue Service. Failure to File Penalty A C-Corp with no tax liability faces no late-filing penalty under this formula, though the IRS can still assess penalties for the failure to file itself.
Getting an Extension
If you can’t meet a deadline, Form 7004 gives you an automatic extension, generally six months for all business entity types.20Internal Revenue Service. Instructions for Form 7004 That moves partnerships and S-Corps from March 15 to September 15, and C-Corps from April 15 to October 15.
An extension gives you more time to file, not more time to pay. Tax owed is still due by the original deadline. For C-Corps, a proper tax estimate must accompany Form 7004, and any underpayment accrues interest and potential penalties from the original due date.
State Obligations Are Separate
Federal IRS obligations and Delaware state obligations run on independent tracks, and you have to satisfy both. The IRS handles income tax, employment tax, and information returns. Delaware enforces its own requirements through the Division of Corporations and Division of Revenue, including the annual franchise tax (a $300 flat tax for LLCs, LPs, and GPs due by June 1; a minimum of $175 for corporations with a maximum of $200,000, or $250,000 for Large Corporate Filers) and the Gross Receipts Tax on in-state activity.21State of Delaware Division of Corporations. How to Calculate Franchise Taxes22Delaware Division of Corporations. LLC/LP/GP Franchise Tax Instructions23Delaware Division of Revenue. Franchise Taxes Falling behind on the state side can void your entity, which then complicates your federal filings.