What Does a Delaware C-Corp Need to File in 2026?

A Simple, Clear Overview for Founders and Business Owners

Delaware continues to be one of the most popular states for incorporation, but staying compliant requires understanding several annual filings. Many founders focus on operations and overlook their core responsibilities, especially around Delaware C corp tax filing, federal requirements, and maintaining good standing. This guide breaks down everything a corporation must file in 2026 to avoid penalties and administrative issues.

Federal Corporate Income Tax (IRS Form 1120)

All U.S. corporations must file Form 1120, the standard C Corp tax return, even if the business had no revenue for the year. Many companies now prefer to file C corporation taxes online for faster processing.

Deadline: April 15, 2026

Failing to file may result in penalties, interest, and delays in future refunds.

Delaware Franchise Tax & Annual Report

Every Delaware corporation must complete the Annual Report and the Delaware franchise tax filing, regardless of revenue. These filings apply even if the corporation remained inactive during the year.

There are two calculation methods:

• Authorised Shares Method
• Assumed Par Value Capital Method – often beneficial for startups

Many companies pay Delaware franchise tax online to simplify recordkeeping and avoid missing the March 1 deadline.

Deadline: March 1, 2026

Penalties: $200 + 1.5% monthly interest

Missing this filing immediately affects good standing, which can complicate fundraising, banking, and compliance.

Delaware Corporate Income Tax (Form 1100)

Corporations must complete a Delaware corporate tax filing only if they:

• Operate in Delaware, or
• Earn income sourced from Delaware customers

The state calculates tax using a sales-only formula, meaning only revenue from Delaware customers impacts the final amount owed. Many founders now file Delaware corporate taxes through the online portal for faster submission.

Essential Documents for 2026 Filings

Accurate Delaware C corp tax filing requires well-organised financial records. Recommended documents include:

Financial data

• Trial balance
• Revenue recognition
• Accrued expenses
• Depreciation
• COGS
• Year-end adjustments

Schedules

• Asset & liability details
• Stock issuances
• Fixed asset list
• Lease obligations
• Software capitalization

Supporting documents

• Bank statements
• Payroll summaries
• Board minutes
• Updated stock ledger

Clean records prevent mismatches between state and federal filings.

Filing Federal Taxes Online

As part of a complete C corp tax filing, companies must include schedules such as:

• Schedule L (Balance Sheet)
• Schedule M-1 (Book vs tax differences)
• Schedule J (Tax calculation)
• Schedule G (Ownership information)

Many corporations now file C-Corp taxes online through the IRS MeF system for faster validation and fewer errors.

Filing Delaware Franchise Tax & Annual Report

To complete this filing, corporations need:

• Delaware file number
• EIN
• Stock information
• Par value
• Director and officer details
• Registered agent information

Most businesses now handle their Delaware C corp filing through the official state website, which provides instant confirmation.

Filing Delaware Corporate Income Tax (Form 1100)

Corporations that operate or generate income in the state must file Form 1100 through Delaware’s online portal. The filing includes:

• Federal taxable income
• Delaware adjustments
• Delaware-sourced sales
• Applicable credits

Only Delaware sales influence the final tax liability.

Paying Federal & State Taxes

Delaware payments: ACH debit, ACH credit, EFT

Federal payments: EFTPS, IRS Direct Pay

Corporations that owe tax must also make quarterly estimated payments using Form 1120-W.

Staying Compliant Year-Round

Good standing depends on consistent, year-round compliance—not only annual tax submissions.

Recommended practices:

• Monthly bookkeeping
• Documented corporate meetings
• Tracking all filing deadlines
• Organised digital records

Even one overdue filing can disrupt banking, fundraising, or legal processes.

Final Takeaway

A Delaware corporation must complete several filings every year, including federal Form 1120, the Delaware Annual Report, the franchise tax payment, and, when applicable, the Delaware corporate income tax return. Staying organised ensures a smooth and accurate Delaware C corp tax filing process.

Whether you complete the filing yourself or choose to file C corp taxes online, clean records and timely submissions help protect the company’s good standing.

For founders who want support with these filings or need help navigating the process, TruSpan Financial assists with federal filings and Delaware C-Corp compliance to ensure all obligations are handled accurately and on schedule.