Corporate Tax Deductions: Depreciation, R&D, COGS, and Interest

A C-Corp can deduct virtually every ordinary and necessary cost of running the business against its 21 percent federal tax, and C-Corp tax deductions cover payroll, rent, utilities, insurance, interest, depreciation, state taxes, and charitable gifts, among many others.1Internal Revenue Service. Publication 542 – Corporations Each deductible dollar cuts the corporate tax bill by roughly 21 cents. What follows is the working list, with the 2026 dollar limits and the traps that catch corporations most often.

The Ordinary and Necessary Baseline

The broadest deduction covers any expense that is both “ordinary” (common in the corporation’s industry) and “necessary” (helpful and appropriate for the operation). If a cost meets both tests, it is generally deductible in the year paid or incurred.2Office of the Law Revision Counsel. 26 USC 162 – Trade or Business Expenses

Everyday items fall squarely in this category: rent or lease payments on office and warehouse space, utilities, property and liability insurance, office supplies, and professional fees paid to accountants for tax work or to attorneys for contract drafting and regulatory compliance.3eCFR. 26 CFR 1.162-1 – Business Expenses Advertising and marketing costs, whether print, broadcast, digital, or public relations work, are fully deductible in the year spent so long as they promote the business rather than attempt to influence legislation.

Dues paid to trade associations, professional groups, and local chambers of commerce qualify. Dues for social, athletic, or country clubs do not, no matter how much business networking happens there. When a trade association uses part of its dues for lobbying, the corporation has to back out that portion; it is not deductible.

Compensation and Employee Benefits

Salaries, wages, and bonuses are deductible as long as the total pay for each person is reasonable relative to the work performed.4Internal Revenue Service. Reasonable Compensation Job Aid for IRS Valuation Professionals The rule rarely bites for rank-and-file staff. It bites hardest on shareholder-executives. If the IRS decides a shareholder-employee’s pay exceeds what similar companies pay for similar work, it can reclassify the excess as a nondeductible dividend. That reclassification is doubly painful: the corporation loses the deduction and the shareholder still owes tax on the payment.

Fringe benefits add a second layer. Employer-paid health insurance premiums are deductible by the corporation and excluded from employees’ wages.5Internal Revenue Service. Employee Benefits Contributions to qualified retirement plans, including 401(k) matching and profit-sharing arrangements, are deductible up to 25 percent of the total compensation paid to eligible plan participants during the year.6Internal Revenue Service. Retirement Topics – 401(k) and Profit-Sharing Plan Contribution Limits Group-term life insurance, educational assistance, and dependent care benefits also reduce taxable income when properly structured.

One benefit surprises employers who assume anything given to employees is deductible. Qualified transportation fringe benefits like transit passes and parking are still tax-free to employees up to $340 per month in 2026, but the corporation cannot deduct the cost. That employer deduction was eliminated for amounts paid after 2017.7Internal Revenue Service. Publication 15-B (2026), Employers Tax Guide to Fringe Benefits

Depreciation, Section 179, and Bonus Depreciation

Property with a useful life of more than a year, such as machinery, vehicles, computers, and office furniture, is generally recovered through annual depreciation rather than deducted in full in year one.8Office of the Law Revision Counsel. 26 USC 167 – Depreciation The standard framework is the Modified Accelerated Cost Recovery System. Computers and light trucks follow a five-year schedule; office furniture and fixtures use seven.9Office of the Law Revision Counsel. 26 USC 168 – Accelerated Cost Recovery System

Two provisions let a corporation accelerate the write-off, often to the full cost in the first year.

Section 179 expensing. A corporation can elect to deduct the full purchase price of qualifying equipment, vehicles, and software in the year the asset is placed in service, up to $2,560,000 for taxable years beginning in 2026. The deduction phases out dollar-for-dollar once total qualifying purchases exceed $4,090,000.10Internal Revenue Service. Revenue Procedure 25-32

Bonus depreciation. Under the One Big Beautiful Bill Act signed in July 2025, 100 percent bonus depreciation is permanently available for qualifying property acquired and placed in service after January 19, 2025. There is no dollar cap. A corporation can elect out and recover the cost under the normal MACRS schedule instead.9Office of the Law Revision Counsel. 26 USC 168 – Accelerated Cost Recovery System

Both provisions apply only to tangible personal property used more than 50 percent for business. Together they mean a corporation buying $2 million of equipment can potentially write off the entire amount in year one.

Research and Development

The rule on research and experimental expenditures reversed course in 2025. Under the original Tax Cuts and Jobs Act treatment, corporations had to capitalize and amortize all research costs over five years for domestic work and 15 for foreign work. The One Big Beautiful Bill Act enacted a new Section 174A that permanently restores full first-year expensing of domestic research and experimental expenditures for taxable years beginning after December 31, 2024.11Office of the Law Revision Counsel. 26 USC 174 – Amortization of Research and Experimental Expenditures

Foreign research and experimental expenditures still must be capitalized and amortized over 15 years, beginning at the midpoint of the taxable year the costs are incurred. Software development costs are treated as research expenditures under these rules, so a C-Corp writing proprietary software domestically can deduct those costs in full.12Office of the Law Revision Counsel. 26 US Code 174 – Amortization of Research and Experimental Expenditures

Business Interest

Interest on business debt (bank loans, lines of credit, mortgages on corporate property) is deductible. For most C-Corps, the deduction is capped at 30 percent of adjusted taxable income for the year, plus any business interest income and floor plan financing interest.13Internal Revenue Service. Questions and Answers About the Limitation on the Deduction for Business Interest Expense Any disallowed interest carries forward indefinitely.

The cap does not apply to smaller corporations. For taxable years beginning in 2026, a corporation meets the small-business exception if its average annual gross receipts over the prior three years do not exceed $32,000,000.10Internal Revenue Service. Revenue Procedure 25-32 Below that threshold, all business interest is deductible without limitation.

Cost of Goods Sold

Corporations that manufacture, purchase, or resell physical products do not deduct inventory as an operating expense. Those costs come out of gross receipts as cost of goods sold before the return ever reaches the deduction lines.14Internal Revenue Service. Form 1125-A, Cost of Goods Sold Included are the price of raw materials or finished goods bought for resale, direct labor, and certain overhead that must be capitalized into inventory under the uniform capitalization rules of Section 263A. Small business taxpayers that meet the gross receipts test are exempt from those uniform capitalization rules.

Startup and Organizational Costs

A new C-Corp can deduct up to $5,000 of startup expenditures and up to $5,000 of organizational costs in the first year it begins business. Each $5,000 allowance phases down dollar-for-dollar once that category exceeds $50,000 and disappears at $55,000. Anything not deducted immediately is amortized evenly over 180 months.15Office of the Law Revision Counsel. 26 US Code 195 – Start-Up Expenditures

Startup costs include market research, scouting locations, and pre-opening employee training. Organizational costs cover the legal and accounting work of incorporating: drafting articles and bylaws, and paying state filing fees. Timing matters. A corporation that spends $60,000 investigating a new business before it opens gets no first-year deduction at all and has to amortize the whole amount over 180 months.

Travel and Meals

Travel expenses are deductible when an employee or officer travels away from the corporation’s tax home on business. Airfare, lodging, rental cars, and incidentals like tips and dry cleaning qualify. For each trip, the corporation needs to document the amount spent, the dates, the destination, and the business purpose.16eCFR. 26 CFR 1.274-5A – Substantiation Requirements Receipts are required for lodging and for any single expense of $25 or more.

Business meals are deductible at 50 percent of the cost, provided the meal is not lavish and a company employee is present. The other diner can be a client, a prospective customer, or another business contact.17Internal Revenue Service. Tax Cuts and Jobs Act – Businesses Food and drink bought during an entertainment event, like a game or a concert, are only deductible if invoiced or purchased separately from the entertainment itself. Bundle the food into the ticket price and the entire cost becomes nondeductible.18Internal Revenue Service. TD 9925 – Meals and Entertainment Expenses Under Section 274

State Taxes, Charitable Gifts, Bad Debts, and Losses

Taxes paid to other governments. A C-Corp can deduct state and local income taxes on its earnings, real estate taxes on property it owns, personal property taxes on business equipment, and the employer’s share of payroll taxes (Social Security, Medicare, and federal and state unemployment).2Office of the Law Revision Counsel. 26 USC 162 – Trade or Business Expenses Federal income tax itself is not deductible.

Charitable contributions. Donations to qualified charities are deductible up to 10 percent of taxable income, calculated before the charitable deduction and certain other adjustments.19Office of the Law Revision Counsel. 26 US Code 170 – Charitable Etc Contributions and Gifts Any excess carries forward up to five years.20Office of the Law Revision Counsel. 26 USC 170 – Charitable Etc Contributions and Gifts Contributions above $250 need a written acknowledgment from the charity, and property donations require a fair market value determination, with high-value gifts usually needing a formal appraisal.

Bad debts. A debt owed to the corporation that has become partly or wholly worthless is deductible, provided the amount was previously included in gross income and the corporation took reasonable steps to collect.21Internal Revenue Service. Topic No. 453, Bad Debt Deduction Typical examples are unpaid invoices from credit sales, unrecoverable loans to suppliers or employees, and loan guarantees the corporation had to honor.

Net operating losses. When deductions exceed gross income for the year, the resulting NOL carries forward with no time limit.22Office of the Law Revision Counsel. 26 USC 172 – Net Operating Loss Deduction For NOLs arising in taxable years after 2017, though, the carryforward can offset only 80 percent of taxable income in any future year. The corporation always pays tax on at least 20 percent of that year’s income. Carrybacks are generally unavailable except for narrow farming losses, so a bad year following profitable ones does not produce a refund; the loss waits for future profits.

What a C-Corp Cannot Deduct

A short list of costs is off-limits regardless of business connection:

The penalty and lobbying rules are the most unforgiving. If a payment resolves a legal violation or attempts to influence legislation, the deduction does not exist, no matter how routine the cost feels in a regulated industry.