Accretion of Bond Discount
The Formal Definition
The progressive upward accounting adjustment of a discount bond's book value toward its par value over its remaining term to maturity, requiring taxable investors to recognize phantom ordinary income annually even if no cash payment is received.
Annual Accretion = (Par Value - Adjusted Cost Basis) / Remaining Years to Maturity (Constant-Yield or Straight-Line Method)
Cole Barrett's Reality Check
The Unvarnished Bottom Line"Buying a deep discount bond sounds like a great capital gains play until the tax authority steps in. If you buy a zero-coupon bond for $600 that matures at $1,000, you don't get to wait ten years to report that $400 gain. The IRS forces you to 'accrete' that discount every single year, billing you tax on phantom interest you haven't received in cash."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: Purchasing $50,000 par value of a 10-year Zero-Coupon Treasury bond for $32,000 in a taxable account
| Execution Metric | Tax-Sheltered Account Holder (Traditional IRA / 401k) | Taxable Account Holder (Original Issue Discount Trap) |
|---|---|---|
| Fee / Rate | $0.00 | $0.00 |
| Spread / Buffer | Held zero-coupon discount paper in a tax-exempt custody wrapper | Held discount bond in standard taxable brokerage account |
| Execution / Status | Annual accretion occurred on paper with zero immediate tax liability | Billed ordinary income tax annually on roughly $1,800 of phantom accreted interest |
| Total Cost / Result | Preserved 100% of compounded capital accumulation | Suffered ongoing cash drag on non-cash paper earnings |
How Brokers Weaponize This Term
Brokerages display zero-coupon bond yields on discovery screens without indicating that taxable accounts will be billed annually on Original Issue Discount (OID) phantom income.
Broker Evaluation Matrix
Cole Approves
Charles Schwab / Interactive Brokers: Provides institutional fixed income tax-lot reports detailing projected annual OID accretion liabilities before purchase confirmation.
Read Audit →Cole Flags / Avoids
Retail Mobile Apps: Lists deep discount corporate and government paper with zero disclosures regarding annual non-cash tax accretion liabilities.
View Trap Details →Frequently Asked Questions
What is Original Issue Discount (OID)?
The difference between a bond's stated redemption price at maturity and its initial issue price; tax authorities treat this discount as interest earned over the life of the bond.
Can accretion of bond discount be avoided entirely?
Yes. Hold zero-coupon bonds or deep-discount debt exclusively inside tax-advantaged accounts like IRAs, or buy municipal bonds exempt from federal income taxation.