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Bond Amortization Structure: Fully vs Balloon | EasyCFA | Wall Street Uni

Fixed Income

Bond Amortization Structure

Interactive visualization comparing fully amortizing and partially amortizing (balloon) bond payment structures. See how interest and principal components change over time, understand balloon payment risk, and compare total cash flows between structures. Essential CFA fixed-income concept.

Subtopic: Fixed-Income Instruments
Level: Fundamental
Status: Featured
Views: 344

Parameters

Bond Structure

balloon_pctBalloon Size (%)%

0100

coupon_rateCoupon Rate (%)%

0.515

maturityMaturity (Years)years

530

show_balanceShow Balance Line

Formula

PV = \sum_{t=1}^{n} \frac{C}{(1+r)^t} + \frac{FV}{(1+r)^n}

Interactive Chart

Bond Amortization Structure

Fully Amortizing

Face Value

$1,000.00

Coupon Rate

6.0%

Maturity

10 years (10 annual)

Payment / Period

$135.87

Fully AmortizingActive

Total Payments

$1,358.70

Total Interest

$358.69

Avg Payment

$135.87

Balloon

$0.00

Partially AmortizingReference

Total Payments

$1,358.70

Total Interest

$358.69

Avg Payment

$135.87

Balloon

$0.00

Interest Difference

$0.00

Equal

Balloon Risk

0.0%

of total balloon payments

Payment Reduction

0.0%

lower periodic with balloon

Total Periods

annual

KEY CFA INTERPRETATIONS

• Fully amortizing bonds reduce credit risk over time as principal declines steadily

• Partially amortizing bonds expose investors to balloon risk — refinancing may fail if credit conditions tighten

• Balloon structures are common in commercial real estate and structured finance

• Lower interim payments do not imply lower total risk — the balloon concentrates risk at maturity

STUDENT TASKS

1. Compare total periodic payments across bond types — which structure has lower interim cash flows?

2. Observe how principal repayment timing differs between the two structures

3. Note the size and risk implications of the balloon payment

4. Relate lower early payments to higher refinancing risk at maturity

Bonds can be structured with different principal repayment schedules. This visualization compares two fundamental structures: fully amortizing and partially amortizing (balloon) bonds.

FULLY AMORTIZING BONDS

A fully amortizing bond repays all principal through regular periodic payments. Each payment is a constant amount that includes both interest and principal components:

Early payments are mostly interest (the outstanding balance is large)

Later payments are mostly principal (the balance has shrunk, so interest is smaller)

By the final payment, the balance reaches exactly zero

The periodic payment is calculated using the annuity formula: PMT = FV x r / (1 - (1+r)^(-n))

PARTIALLY AMORTIZING (BALLOON) BONDS

A partially amortizing bond does not fully repay principal through regular payments. A large lump sum (the balloon payment) is due at maturity:

Periodic payments are lower than the fully amortizing case

The payment amortizes only a portion of the face value (FV minus balloon)

At maturity, the remaining balance equals the balloon amount

The borrower must either refinance or have cash available for the balloon

PAYMENT FORMULA

For any bond with face value FV, balloon amount B, periodic rate r, and n periods:

PMT = (FV - B x (1+r)^(-n)) x r / (1 - (1+r)^(-n))

When B = 0 (fully amortizing): standard annuity formula

When B = FV (interest only): PMT = FV x r

INTEREST VS PRINCIPAL BREAKDOWN

Each periodic payment splits into two components:

Interest = Outstanding Balance x Periodic Rate

Principal = Total Payment - Interest

As the balance declines, the interest portion shrinks and the principal portion grows. This pattern is visible in the stacked bar chart as the amber (interest) portion decreases while the blue (principal) increases.

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Study aids

Working with this chart

The errors candidates make on this topic, and what to carry into the exam.

Common mistakes

Confusing lower payments with lower cost: Balloon bonds have lower periodic payments but often result in higher total interest paid over the bond's life because the balance stays elevated longer
Forgetting the balloon is in addition to the last regular payment: The final period of a balloon bond has BOTH the regular periodic payment AND the balloon. Students often forget to include one or the other
Applying the wrong periodic rate: When payment frequency is semiannual, the periodic rate is the annual rate divided by 2, and the number of periods is years times 2. Do not use the annual rate with semiannual periods
Ignoring refinancing risk in analysis: A balloon bond at 0% coupon is not risk-free. The balloon payment creates significant refinancing risk regardless of the interest rate
Assuming bullet bonds are a different concept: A bullet bond (standard corporate bond) is simply the extreme case of a balloon structure where balloon = 100% of face value. The regular payments are interest-only
Confusing amortization with depreciation: Amortization in bond context refers to principal repayment schedule. It is unrelated to accounting depreciation of assets
Double-counting the balloon in total cost: The balloon is return of principal, not an additional cost. Total interest = sum of all payments minus face value

Exam tips

Know both structures: CFA Level I tests the difference between fully amortizing and partially amortizing bonds. Be ready to calculate payments for either structure
Payment formula: Memorize PMT = FV x r / (1 - (1+r)^(-n)) for fully amortizing. For balloon, adjust the numerator to account for the present value of the balloon
Direction of effects: Higher coupon = higher payment but same principal repaid. Longer maturity = lower payment but more total interest. Higher balloon = lower payment but more refinancing risk
Credit risk comparison: Always state that fully amortizing bonds reduce credit risk over time while balloon bonds concentrate risk at maturity. This is a frequently tested conceptual question
Total interest comparison: Be prepared to calculate total interest for each structure. The balloon bond always pays more total interest (assuming same rate and maturity)