- Abandonment
- Ability to pay
- Above-the-line deduction
- Abstract of title
- Accelerated cost recovery system
- Accelerated depreciation
- Acceleration clause
- Acceptance
- Accident and health insurance
- Accounting method
- Accounts receivable turnover
- Accrual accounting
- Acquiring financial institution
- Acquisition fee
- Actual cash value
- Actuary
- Ad valorem tax
- Add-on interest
- Add-on interest loan
- Add-ons
- Addendum
- Additional principal payment
- Ademption
- Adjustable-rate mortgage
- Adjusted balance
- Adjusted basis
- Adjusted gross income
- Adjustments to income
- Administrator
- Adoption credit
- Adoption taxpayer identification number (ATIN)
- Advance medical directive
- Adverse possession
- Affinity credit card
- Affordable Care Act
- Aftercare
- Aggressive growth
- Agreed boundary
- Agreement of sale
- Air miles
- Alienation clause
- Allowable cost
- Allowance
- Alpha
- Alternative minimum tax
- Alternative mortgage
- Ambulatory benefits
- Amended return
- American Opportunity Tax Credit
- Amortization