Bond Pricing
A bond's price is the present value of all its future cash flows:
Price = Σ [Coupon / (1+YTM)^t] + [Face Value / (1+YTM)^n]
For a semi-annual bond: use semi-annual coupon = Annual Coupon / 2, and semi-annual YTM = YTM / 2, and n = years × 2.
Example: 5% annual coupon, 3-year bond, face value ₹1,000, YTM = 6%:
- Year 1: 50 / 1.06 = 47.17
- Year 2: 50 / 1.06² = 44.50
- Year 3: 50 / 1.06³ = 41.98 + 1000/1.06³ = 839.62
- Price = 47.17 + 44.50 + 41.98 + 839.62 = ₹973.27 (discount bond — coupon < YTM)
Price-Yield Relationship
- When YTM = Coupon rate: Price = Face Value (par bond)
- When YTM > Coupon rate: Price < Face Value (discount bond)
- When YTM < Coupon rate: Price > Face Value (premium bond)
Yield Measures
- YTM (Yield to Maturity): Discount rate equating PV of cash flows to price. Assumes coupons reinvested at YTM and held to maturity.
- Yield to Call (YTC): YTM calculated to the call date at call price — relevant for callable bonds in falling rate environments.
- Current Yield: Annual Coupon / Current Price. Simple but ignores capital gain/loss and reinvestment income.
- Effective Yield: For bonds with embedded options, uses option-adjusted spread (OAS) instead of YTM.
Duration
Macaulay Duration
The weighted average time (in years) to receive all cash flows, where weights = PV of each cash flow / Total Price.
Zero-coupon bond: Macaulay Duration = Maturity (all cash flow at end)
Coupon bond: Macaulay Duration < Maturity
Modified Duration
Modified Duration = Macaulay Duration / (1 + YTM/m)
where m = compounding periods per year.
Interpretation: If Modified Duration = 5, then a 1% rise in yield → approximately 5% price decline.
% Change in Price ≈ −Modified Duration × ΔYield
Example: Bond with Modified Duration = 7. Yield rises 0.50%: Price change ≈ −7 × 0.005 = −3.5%
Dollar Duration (DV01)
DV01 (Dollar Value of a Basis Point) = Modified Duration × Price × 0.0001
Used in portfolio hedging — tells you $ change in bond value per 1bp yield move.
Convexity
Duration is a linear approximation of price-yield relationship. Convexity captures the curvature.
More accurate price change = (−Modified Duration × ΔY) + (½ × Convexity × ΔY²)
Positive convexity is desirable: for a given yield move, price rises more than duration predicts and falls less. Higher convexity bonds command a premium.
Callable bonds have negative convexity at low yield levels (price is capped by call price even as yields fall).
Credit Analysis
Credit Rating Framework
| S&P/Fitch | Moody's | Category |
|---|---|---|
| AAA, AA, A, BBB | Aaa, Aa, A, Baa | Investment Grade |
| BB, B | Ba, B | Speculative / High Yield |
| CCC, CC, C, D | Caa, Ca, C | Distressed / Default |
Four Cs of Credit Analysis
- Capacity: Ability to repay — EBITDA coverage, leverage ratios, free cash flow generation
- Collateral: Asset quality — liquidation value in default scenario
- Covenants: Debt covenants protecting bondholders (maintenance covenants, incurrence covenants)
- Character: Management quality, track record, governance
Credit Spread Analysis
Credit Spread = Bond YTM − Risk-Free Rate (comparable government bond)
Spread reflects: Default risk premium + Liquidity premium
In recessions, spreads widen dramatically (flight to quality). In expansion, spreads narrow.