19 Business Expense Categories Delaware C-Corp Founders Should Track

Your Delaware C-corp is a separate taxpayer. Its operating expenses belong in corporate records and feed into its corporate tax return, generally Form 1120. Paying a company expense personally does not turn your startup into a sole proprietorship or make Schedule C the right place to claim it.

Good categorization helps your accountant determine what is currently deductible, what must be capitalized, and what needs special treatment. An expense category is not a promise of a deduction. Start with the Form 1120 instructions and keep evidence of business purpose.

People and professional support

1. Contractor services. Separate engineering, design, and other outside services. Keep contracts, invoices, payment records, and tax documentation. Research-related costs can require distinct tax treatment, so preserve project and work-location details.

2. Employee benefits. Record company health coverage and other benefits through the proper employer arrangements. Founder benefits need corporate and payroll analysis, rather than a self-employed health-insurance shortcut.

3. Retirement plan costs. Track employer contributions and plan administration separately. Eligibility, contribution limits, and timing depend on the plan. Personal IRA contributions are not automatically corporate expenses.

4. Legal and accounting services. Distinguish routine operating advice from formation, financing, acquisition, or asset-related work. A legal invoice may need to be split among several treatments.

Customer acquisition and transactions

5. Advertising. Track paid campaigns, creative production, and agency work by business purpose. Keep prelaunch and ongoing operating costs distinguishable.

6. Commissions and transaction fees. Record sales commissions, merchant fees, and platform charges separately. Financial-statement timing and tax treatment may differ, especially for contract-acquisition costs.

Workplace and equipment

7. Office operating expenses. Identify cleaning, routine office services, and similar costs. Avoid duplicating expenses imported from both cards and reimbursement software.

8. Rent and leases. Separate office rent, coworking, and equipment leases. Security deposits and prepaid amounts are not necessarily immediate expenses.

9. Utilities and connectivity. Track business internet, electricity, and telephone costs. Support any allocation between company and personal use.

10. Supplies. Keep consumable office and operating supplies distinct from equipment, inventory, and research materials. Their timing rules can differ.

11. Equipment and depreciation. Maintain an asset register for laptops, furniture, and other durable purchases, including cost and placed-in-service dates. Available expensing elections and depreciation rules require review.

12. Repairs and maintenance. Distinguish ordinary maintenance from improvements or replacements that must be capitalized. The invoice label alone does not decide the treatment.

13. Home workspace reimbursements. A founder working at home should use a properly reviewed corporate reimbursement arrangement where appropriate. Do not automatically apply a sole proprietor's home-office formula to the founder's personal return.

Risk, financing, and administration

14. Business insurance. Track cyber, liability, directors-and-officers, and other company policies. Separate personal coverage and prepaid periods.

15. Interest. Distinguish interest from loan principal and financing fees. Business-interest limitations and capitalization rules can affect timing.

16. Formation and startup costs. Keep organizational costs and pre-opening startup expenditures identifiable. Special deduction and amortization rules apply; raising equity introduces additional distinctions.

17. Taxes and licenses. Separate employer payroll taxes, state taxes, Delaware franchise tax, and licenses. Federal corporate income tax is not deductible in computing federal taxable income. Sales tax collected for a state is generally a liability, not your operating expense.

Travel and transportation

18. Business vehicle use. Keep mileage and business-purpose records for qualifying company reimbursements. Ordinary commuting is generally personal. Avoid reimbursing the same cost through multiple methods.

19. Travel and meals. Document destination, dates, attendees, and business purpose. Meals are generally subject to a 50% limit unless an exception applies; entertainment is generally nondeductible. The old temporary restaurant-meal exception is not a general 2026 rule. See IRS Publication 463.

Give research spending its own supporting detail

Engineering expenses can cross several categories above. Domestic research expenditures generally may be deducted under Section 174A for tax years beginning after 2024, while foreign research generally remains subject to 15-year amortization. Elections and transition rules require careful review. The IRS Section 174A guidance explains implementation.

The R&D credit is a separate analysis, not an automatic consequence of booking development costs. Preserve project records, payroll detail, contractor terms, and work locations for your tax team.

Build one reimbursement and close process

For founder-paid company costs, document the expense and use an approved reimbursement process. An accountable plan requires business connection, substantiation, and return of excess advances. Reconcile reimbursements to the ledger so costs are recorded once.

Review these categories during the monthly close. Accurate records support both your corporate return and the financial statements you use to manage runway.

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