Key Takeaways

  • Business expense must be "Ordinary" and "Necessary" under §162.
  • "Ordinary" = common and accepted in the trade/business.
  • "Necessary" = helpful and appropriate (not indispensable).
  • "Reasonableness" applies strictly to compensation and related parties.
  • Personal expenses are never deductible (§262).
  • Business vs. investment vs. personal = critical distinction.
Last updated: January 2026

Ordinary & Necessary Test

Why This Matters for the Exam

The "Ordinary and Necessary" test is foundational to Part 2. Every business expense question starts here. The exam tests the definitions and the reasonableness requirement.

Exam Note: For the May 2025 - February 2026 testing window, you are tested on §162 rules as of December 31, 2024 (Tax Year 2024).

Expect at least 3-4 questions on this standard.

Section 162: The Foundation

ElementMeaning
§162Trade or business expense deduction
OrdinaryCommon and accepted in the industry
NecessaryHelpful and appropriate (not essential)
ReasonableAmount must be fair market value

The "Ordinary" Test

FactorDescription
Industry standardCommon in that specific business
Context mattersVaries by taxpayer's field
Not recurringDoesn't need to happen every year

Example: Professional athlete's supplements = ordinary. Freelance accountant's supplements = probably not ordinary.

The "Necessary" Test

FactorDescription
HelpfulContributes to profit potential
AppropriateFits the business purpose
NOT requiredDoes not need to be essential

Key Point: IRS won't second-guess business judgment unless expense is clearly unrelated.

The "Reasonableness" Requirement

AreaApplication
Officer compensationExcess = constructive dividend
Related party transactionsMust be at FMV
Result of excessDisallowed or reclassified

Officer Compensation Example

Company PaymentIRS Analysis
Owner-employee salary: $500,000
Comparable non-owner salary: $200,000
Reasonable:$200,000
Excess (constructive dividend):$300,000
C corp consequence:Double taxation

Business vs. Personal vs. Investment

CategoryCode SectionDeductibility
Trade or business§162Fully deductible (above-the-line)
Investment§212Limited (below-the-line)
Personal§262NEVER deductible

Capital vs. Expense

TypeTreatment
ExpenseDeduct fully in year paid/incurred
CapitalBenefit >1 year = capitalize + depreciate

Real-World Scenario

Scenario: Owner pays 16-year-old daughter $50,000/year for 10 hrs/week phone work. Market rate is $15/hr.

  • Reasonable compensation: 52 weeks × 10 hrs × $15 = $7,800.
  • Excess: $50,000 - $7,800 = $42,200 (non-deductible gift).
  • Deductible: $7,800 only.

On the Exam

Expect 3-4 questions on the O&N test, typically:

  1. Definition Questions: "What does 'necessary' mean?"
  2. Reasonableness Questions: "How much salary is deductible?"
  3. Classification Questions: "Is this business, investment, or personal?"

The key is to remember: Ordinary = common in industry. Necessary = helpful (not essential). Reasonable = FMV. Personal = never deductible.

Test Your Knowledge

Tech startup buys $500 coffee machine. IRS says $50 would suffice. Is the $500 deductible?

A
B
C
D
Test Your Knowledge

Owner pays daughter $50,000/year for 10 hrs/week. Market rate $15/hr. Deductible amount?

A
B
C
D
Test Your Knowledge

Which Code section defines business deductions?

A
B
C
D