Bond Pricing & Yields
This page consolidates the bond math and pricing logic from Ch15 into one focused exam-prep reference. The structural details of bonds (callable / serial / convertible, secured / debenture, registered / bearer) are in LongTermFinancing. This page is just about how bond prices and yields move and how to read a quote.
graph TD BR["Bond Rate vs Market Rate"] BR -->|"Bond rate > market rate"| PR["Premium Bond<br/>Sells ABOVE face value"] BR -->|"Bond rate = market rate"| PAR["Par Bond<br/>Sells AT face value"] BR -->|"Bond rate < market rate"| DI["Discount Bond<br/>Sells BELOW face value"] IR["Interest Rates Rise<br/>(market)"] -->|"Existing bonds less attractive"| BP1["Bond Prices FALL"] IR2["Interest Rates Fall<br/>(market)"] -->|"Existing bonds more attractive"| BP2["Bond Prices RISE"]
How It Appears Per Course
ADMN 201
LO4 covers long-term financing through bonds. This page extracts the price/yield mechanics that the textbook treats as a numerical sub-topic — the kind of question that asks “if rates go up, what happens to the price of an existing bond?”
The Inverse Relationship: Rates vs. Prices
The most important rule in Ch15 bond material:
When market interest rates rise, existing bond prices fall. When market interest rates fall, existing bond prices rise.
Why this works (the intuition):
- You hold a bond paying 4% interest.
- The market rate suddenly rises to 6%.
- New bonds being issued pay 6%. Why would anyone buy your 4% bond at face value?
- They wouldn’t — so to sell, you must drop your price below face value (a discount).
- The discount makes your bond’s effective yield match the new 6% market rate.
This is why bond prices move daily even when nothing about the issuing company changed.
Exam trap: This was a 🟦 resolved error in the study plan (2026-04-25 — “Bond pricing direction: rates ↑ → price ↓”). Drill until automatic.
Premium vs. Discount Bonds
A bond’s market price depends on three things:
- Its stated (coupon) interest rate
- The going (market) rate of interest on similar-quality bonds
- Its redemption / maturity date
| Situation | Sells At | Reason |
|---|---|---|
| Stated rate > market rate | Premium (above face value) | Bond pays more than alternatives — investors compete for it |
| Stated rate = market rate | Par (at face value) | Bond is exactly competitive |
| Stated rate < market rate | Discount (below face value) | Bond pays less than alternatives — must drop price to sell |
The premium/discount size depends on how far in the future the maturity date is. A long-dated bond is more sensitive to rate moves than a short-dated one.
Reading a Bond Quote
Bond prices are quoted as a % of face value (NOT in dollars). Face value is typically $1,000 — but the quote ignores the dollar sign and the 1,000.
| Quote | What it means |
|---|---|
| 100 | At par — 1,000 |
| 85 | 1,000) — discount bond |
| 101.92 | 1,000) — premium bond |
| 155.25 | 1,000) — deep premium |
Coupon (interest) rates are also quoted as % of par:
- “6½s” pays 6.5% of par per year (1,000 face value)
- Interest is typically paid semi-annually at half the stated rate ($32.50 every 6 months)
Bond Yield Calculation
Bond Yield = Annual Interest Paid ÷ Current Market Price
This is the real return you earn — not the coupon rate, which is fixed against face value.
Worked Example
You bought a 650**. Stated rate 6%; matures 2030.
- Annual interest received: 60/year**
- Yield based on actual investment: 650 = 9.2%
- At maturity in 2030, you also receive the full 350 capital gain on top of the yield.
- Your effective total return is therefore even higher than 9.2%.
Key insight: Bond yield is what matters, not coupon rate. A 6% coupon on a discounted bond gives you a higher yield than 6%; a 6% coupon on a premium bond gives you less.
Bond Ratings
Default risk = the chance that the issuer will miss a promised payment. Rating agencies grade bonds:
| Rating Agency | High Grade | Investment Grade | Speculative | Junk |
|---|---|---|---|---|
| Moody’s | Aaa, Aa | A, Baa | Ba, B | Caa, C |
| Standard & Poor’s | AAA, AA | A, BBB | BB, B | CCC, D |
- Higher rating → lower default risk → lower interest rate the issuer must offer
- Lower rating → higher default risk → issuer must pay higher interest to attract investors (“junk bonds”)
- Example: Moody’s downgraded Enbridge after its $37B Spectra Energy acquisition due to integration/execution risk — debt got more expensive
How a Premium/Discount Resolves at Maturity
This is the often-missed exam point: regardless of what you paid, you receive face value at maturity.
| Scenario | Payment at maturity | Capital gain/loss |
|---|---|---|
| Bought premium ($1,100) | $1,000 | Loss of $100 |
| Bought at par ($1,000) | $1,000 | $0 |
| Bought at discount ($800) | $1,000 | Gain of $200 |
So a premium bond’s higher coupon is partially eaten by the capital loss at maturity. The yield calculation (above) accounts for this — which is why yield is the right comparison metric.
Cross-Course Connections
LongTermFinancing — full bond structure: callable / serial / convertible, secured / debenture, registered / bearer
SecuritiesMarkets — the secondary market where existing bonds trade
InvestmentVehicles — bond ETFs and bond mutual funds package these instruments for retail
DiversificationAndROI — bonds are the lower-risk leg of asset allocation
BankOfCanada — Bank of Canada rate decisions move the “market rate” that determines bond prices
Deeper Reference (ACC 926 — archived)
- PresentValueMeasurement — the PV/FV mechanics behind why bond prices move with rates (effective interest method)
- PresentValue-LongTermFinancing — connection: NPV intuition ↔ PV/FV/annuity formulas
Key Points for Exam/Study
- Rates ↑ → Bond Prices ↓ (and vice versa) — the single most important rule
- Premium: stated rate > market rate; sells above face value
- Discount: stated rate < market rate; sells below face value
- Par: stated rate = market rate; sells at face value
- Bond quote of 85 = 1,000 bond; quote of 101.92 = $1,019.20
- “6½s” = pays 6.5% of par annually; usually paid semi-annually
- Yield = Annual Interest ÷ Current Market Price (not the coupon rate)
- Bought at 1,000 face → 9.2% yield (plus eventual $350 capital gain at maturity)
- Moody’s: Aaa > Aa > A > Baa > Ba > B > Caa > C
- S&P: AAA > AA > A > BBB > BB > B > CCC > D
- Junk bonds = low rating → must pay high interest to attract investors
Open Questions
- How does a callable bond’s price react differently to falling rates than a non-callable bond?
- Why do long-dated bonds move more than short-dated bonds for the same rate change?