Background and why it matters
Federal tax law is organized by Internal Revenue Code sections that spell out what expenses you can deduct, how to recover costs (depreciation), and when special deductions or credits apply. Changes since the Tax Cuts and Jobs Act (TCJA) of 2017—most notably the creation of the Section 199A Qualified Business Income (QBI) deduction and changes to depreciation—mean owners must track both statutory rules and annual IRS guidance to use these provisions correctly (IRS, Publication 535).
How these sections work in practice
- Section 162: Allows deduction of ordinary and necessary business expenses (wages, rent, supplies). Documentation and a clear business purpose are required (IRS Pub. 535).
- Section 179: Lets qualifying businesses elect to immediately expense the cost of eligible tangible property (equipment, off‑the‑shelf software) up to dollar limits that are set annually; unused amounts may be limited by taxable income (see FinHelp’s Section 179 guide).
- Section 168(k) (bonus depreciation): Permits additional first‑year depreciation for qualifying property; the percentage phases down per TCJA rules after 2022, so consult current IRS guidance before applying it.
- Section 199A (QBI deduction): Provides many pass‑through owners (sole proprietors, partners, S‑corp shareholders) a deduction of up to 20% of qualified business income subject to income and trade/service limits—eligibility rules and calculations can be complex (FinHelp’s 199A overview).
- Section 195: Governs start‑up and organizational costs and the election to amortize or deduct a limited amount in the first year.
- Section 1244: Allows ordinary‑loss treatment for qualifying small business stock losses, which can be more favorable than capital‑loss treatment for individual shareholders.
- Section 401(k) and retirement rules: Contributions to qualified plans reduce taxable income for owners and employees and are an important tax‑efficient compensation tool.
Real‑world examples (short)
- Equipment purchase: A retail owner I worked with used a Section 179 election to expense a $50,000 POS system in year one, reducing taxable income and improving short‑term cash flow. When Section 179 is not available or is limited by income, a combination of bonus depreciation and regular MACRS depreciation can be used.
- QBI claim: A sole proprietor who tracked net qualified business income and properly allocated employee wages and W‑2 wages avoided an overstated deduction and passed IRS scrutiny when audited.
Who is affected and common eligibility rules
- Most active trade or business owners (Schedule C filers, partners, S‑corp shareholders) will encounter Sections 162, 179, 168(k), and 199A.
- Corporations (C corps) use depreciation and Section 179 differently; QBI does not apply to C corps.
- Eligibility for specific benefits (199A, Section 179 limits, start‑up cost election under 195) depends on business type, taxable income, asset type, and whether property was financed or leased.
Practical professional tips
- Stay current: IRS rules and interpretation can change. Bookmark IRS business pages and consult updated FinHelp glossaries for pratical examples. (IRS business pages; FinHelp resources)
- Keep contemporaneous records: invoices, receipts, purchase dates, mileage logs, and capitalization schedules are essential for audits and for applying elections like Section 179.
- Use the right form and election: make timely elections (for example, Section 179 is made on the business return) and attach required statements when necessary.
- Coordinate retirement and compensation planning: maximizing deductible retirement plan contributions can lower taxable income and interact with QBI thresholds.
- When in doubt, document the business purpose and consult a tax pro—complex rules (199A wage limits, hobby vs. business tests) are high audit focus areas.
Quick reference table: commonly used code sections
| Code section | Primary benefit | Notes |
|---|---|---|
| Section 162 | Ordinary & necessary business expense deductions | Base rule for deductible expenses (IRS Pub. 535) |
| Section 179 | Immediate expensing of qualifying property | Dollar limits and taxable income tests apply; see FinHelp: Section 179 Deduction |
| Section 168(k) | Bonus depreciation (first‑year) | Percentage phases down after 2022 per TCJA—check current year rate |
| Section 199A | Qualified Business Income (QBI) deduction | Up to 20% for pass‑throughs; subject to income and service‑trade limitations (FinHelp: 199A overview) |
| Section 195 | Start‑up and organizational costs | Election allows limited current deduction and amortization over 15 years |
| Section 1244 | Ordinary loss for small business stock | Can convert capital losses into ordinary losses for individual shareholders |
Common mistakes and how to avoid them
- Misclassifying workers: Incorrectly treating employees as independent contractors can trigger payroll tax liabilities and penalties. Use IRS guidance and Form SS‑8 where classification is unclear.
- Overusing Section 179 without checking limits: Section 179 is limited by the business’s taxable income and annual dollar caps; exceeding limits can create unexpected disallowed amounts.
- Forgetting elections or proper forms: Elections under Sections 179 and 195 must be made correctly and documented on returns.
- Poor recordkeeping: Lack of receipts, mileage logs, or depreciation schedules increases audit risk and may disallow deductions.
FAQ (brief)
Q: Can a small business use both Section 179 and bonus depreciation?
A: Yes. Many businesses use Section 179 first (for eligible property and to the extent of limits) and then apply bonus depreciation to remaining eligible basis. The optimal mix depends on taxable income, future profit expectations, and state conformity rules.
Q: Does the QBI deduction apply to C corporations?
A: No. The QBI (Section 199A) deduction is available to owners of pass‑through entities and sole proprietors, not to C corporations.
Q: Are start‑up expenses immediately deductible?
A: Section 195 allows a limited immediate deduction (subject to statutory caps) with the remainder amortized over 15 years; rules and thresholds apply so confirm current limits before claiming.
Selected internal resources
- For practical guidance on expensing equipment, see FinHelp’s guide on Section 179 Deduction: https://finhelp.io/glossary/section-179-deduction/
- For details, examples, and year‑specific QBI rules, see FinHelp’s Section 199A overview: https://finhelp.io/glossary/section-199a-qualified-business-income-deduction-overview/
- Annual compliance checklist that pairs these code sections with return deadlines: https://finhelp.io/glossary/annual-tax-compliance-checklist-for-small-business-owners/
Authoritative sources and further reading
- IRS, Publication 535, Business Expenses: https://www.irs.gov/pub/irs-pdf/p535.pdf
- IRS, Section 179 Deduction (small business page): https://www.irs.gov/businesses/small-businesses-self-employed/section-179-deduction
- IRS, Qualified Business Income Deduction (Section 199A) guidance and FAQs: https://www.irs.gov/newsroom/qualified-business-income-deduction-section-199a
- IRS, Publication 946, How to Depreciate Property: https://www.irs.gov/pub/irs-pdf/p946.pdf
Professional disclaimer
This article is educational and does not replace personalized tax advice. Tax outcomes depend on facts and elections specific to your business. Consult a qualified tax advisor or CPA before making filing decisions.
Author note
In my 15+ years working with small businesses I’ve found that timely elections and simple recordkeeping often make the biggest difference in tax outcomes. Small, consistent processes—like a running capitalization schedule and yearly review with your tax advisor—prevent missed deductions and audit headaches.
