
SFM Formulae & Concepts with Fully Detailed Examples
Revision blog covering bond valuation, equity models, portfolio theory, derivatives, forex & international finance—each with complete step-by-step examples.
1. Bond Valuation
1.1 Present Value of Future Cash Flows
Formula:
Price = Σt=1 to n (Coupon ÷ (1 + r)t) + (Redeeming Value ÷ (1 + r)n)
Detailed Example:
A 5-year bond with:
- Face value (Redemption) = ₹1,000
- Annual coupon = 8% of face value = ₹80
- Required yield (r) = 10%
Step 1: List cash flows:
- Year 1–5 coupon: ₹80 each
- Year 5 redemption: ₹1,000 + ₹80 = ₹1,080
Step 2: Discount each cash flow:
Year (t) | Cash Flow | Discount Factor (1.10t) | Present Value |
---|---|---|---|
1 | ₹80 | 1.10 | ₹80 ÷ 1.10 = ₹72.73 |
2 | ₹80 | 1.21 | ₹80 ÷ 1.21 = ₹66.12 |
3 | ₹80 | 1.331 | ₹80 ÷ 1.331 = ₹60.12 |
4 | ₹80 | 1.4641 | ₹80 ÷ 1.4641 = ₹54.64 |
5 | ₹1,080 | 1.6105 | ₹1,080 ÷ 1.6105 = ₹670.79 |
Step 3: Sum all present values:
₹72.73 + ₹66.12 + ₹60.12 + ₹54.64 + ₹670.79 = ₹924.40
1.2 Yield to Maturity (YTM)
Approximate Formula:
YTM ≈ [Coupon + (Redeeming Value – Price)/n] ÷ [(Price + Redeeming Value)/2]
Detailed Example:
From previous example, Price ≈ ₹924.40, Coupon = ₹80, Redemption = ₹1,000, n = 5 years
Step 1: Compute numerator:
Coupon + (Redemption – Price)/n = 80 + (1,000 – 924.40)/5 = 80 + 15.12 = ₹95.12
Step 2: Compute denominator:
(Price + Redemption)/2 = (924.40 + 1,000)/2 = ₹962.20
Step 3: YTM ≈ 95.12 ÷ 962.20 = 0.0989 = 9.89%
1.3 Macaulay & Modified Duration
Macaulay Duration Formula:
D = Σ[t × PV(CFt)] ÷ Price
Modified Duration: D ÷ (1 + YTM)
Detailed Example:
Use cash flows & PV from Section 1.1 and Price = ₹924.40, YTM = 9.89%.
Step 1: Multiply each PV by its year:
Year (t) | PV(CFt) | t × PV |
---|---|---|
1 | ₹72.73 | 1 × 72.73 = 72.73 |
2 | ₹66.12 | 2 × 66.12 = 132.24 |
3 | ₹60.12 | 3 × 60.12 = 180.36 |
4 | ₹54.64 | 4 × 54.64 = 218.56 |
5 | ₹670.79 | 5 × 670.79 = 3,353.95 |
Step 2: Sum weighted PVs = 72.73 + 132.24 + 180.36 + 218.56 + 3,353.95 = ₹3,957.84
Step 3: Macaulay Duration = 3,957.84 ÷ 924.40 ≈ 4.28 years
Step 4: Modified Duration = 4.28 ÷ 1.0989 ≈ 3.90 years
2. Equity Valuation
2.1 Gordon’s Growth Model
Formula:
P₀ = D₁ ÷ (Ke − g)
where D₁ = D₀ × (1 + g)
Detailed Example:
- Last year’s dividend D₀ = ₹4
- Growth rate g = 5%
- Required return Ke = 12%
Step 1: Compute D₁ = 4 × 1.05 = ₹4.20
Step 2: P₀ = 4.20 ÷ (0.12 − 0.05) = 4.20 ÷ 0.07 = ₹60.00
2.2 Multi-Stage Dividend Model
High-growth for first n years, then stable growth thereafter.
Detailed Example:
- D₀ = ₹2
- High-growth g₁ = 20% for 3 years
- Stable growth g₂ = 8% thereafter
- Required return Ke = 14%
Step 1: Compute dividends:
- D₁ = 2 × 1.20 = ₹2.40
- D₂ = 2.40 × 1.20 = ₹2.88
- D₃ = 2.88 × 1.20 = ₹3.46
- D₄ = 3.46 × 1.08 = ₹3.74 (first stable dividend)
Step 2: Terminal value at t=3:
TV₃ = D₄ ÷ (Ke − g₂) = 3.74 ÷ (0.14 − 0.08) = 3.74 ÷ 0.06 = ₹62.33
Step 3: Discount D₁–D₃ and TV₃ back to present:
t | Cash Flow | Discount Factor (1.14³) | PV |
---|---|---|---|
1 | ₹2.40 | 1.14 | 2.40 ÷ 1.14 = ₹2.11 |
2 | ₹2.88 | 1.2996 | 2.88 ÷ 1.2996 = ₹2.22 |
3 | ₹3.46 | 1.4815 | 3.46 ÷ 1.4815 = ₹2.34 |
3 | TV₃ = ₹62.33 | 1.4815 | 62.33 ÷ 1.4815 = ₹42.06 |
Step 4: Sum PVs = 2.11 + 2.22 + 2.34 + 42.06 = ₹48.73
2.3 Free Cash Flow to Firm (FCFF)
Formula:
FCFF = PAT + Depreciation – Capital Expenditure – ΔWorking Capital
Detailed Example:
- Profit after tax (PAT) = ₹120 Cr
- Depreciation = ₹15 Cr
- Capital expenditure = ₹25 Cr
- Increase in working capital = ₹10 Cr
FCFF = 120 + 15 – 25 – 10 = ₹100 Cr
Value of firm = FCFF ÷ (WACC − g) = 100 ÷ (0.12 − 0.04) = 100 ÷ 0.08 = ₹1,250 Cr
2.4 Free Cash Flow to Equity (FCFE)
Formula:
FCFE = FCFF – Interest × (1 − t) + Net Borrowing
Detailed Example:
- FCFF = ₹100 Cr
- Interest = ₹20 Cr, Tax rate t = 30%
- Net new borrowings = ₹10 Cr
Interest after tax = 20 × (1 − 0.30) = ₹14 Cr
FCFE = 100 − 14 + 10 = ₹96 Cr
Value of equity = FCFE ÷ (Ke − g) = 96 ÷ (0.14 − 0.06) = 96 ÷ 0.08 = ₹1,200 Cr
3. Portfolio Management
3.1 Return of a Single Security
Formula:
R = (P₁ − P₀ + D) ÷ P₀ × 100%
Detailed Example:
- Purchase price P₀ = ₹200
- Sale price P₁ = ₹240
- Dividend D = ₹10
Return = (240 − 200 + 10) ÷ 200 × 100% = 50 ÷ 200 × 100% = 25%
3.2 Portfolio Return
Formula:
Rp = Σ(wᵢ × Rᵢ)
Detailed Example:
- Asset A: weight 60%, return 15%
- Asset B: weight 40%, return 8%
Rp = 0.60×15% + 0.40×8% = 9% + 3.2% = 12.2%
3.3 Portfolio Risk (Two Assets)
Formula:
σp² = w₁²σ₁² + w₂²σ₂² + 2w₁w₂σ₁σ₂ρ
Detailed Example:
- σ₁ = 12%, σ₂ = 20%, correlation ρ = 0.4
- w₁ = 0.70, w₂ = 0.30
σp² = (0.70²×0.12²) + (0.30²×0.20²) + 2×0.70×0.30×0.12×0.20×0.4
= 0.49×0.0144 + 0.09×0.04 + 2×0.70×0.30×0.024×0.4
= 0.007056 + 0.0036 + 2×0.70×0.30×0.0096
= 0.007056 + 0.0036 + 0.004032 = 0.014688 → σp = √0.014688 ≈ 12.12%
3.4 CAPM
Formula:
Ke = Rf + β × (Rm − Rf)
Detailed Example:
- Risk-free rate Rf = 6%
- Market return Rm = 14%
- Security beta β = 1.3
Ke = 6% + 1.3×(14% − 6%) = 6% + 1.3×8% = 6% + 10.4% = 16.4%
4. Mutual Funds
4.1 Net Asset Value (NAV)
Formula:
NAV = (Total Assets − Total Liabilities) ÷ Total Outstanding Units
Detailed Example:
- Total assets under management = ₹500 Cr
- Total liabilities = ₹20 Cr
- Total units = 48 Cr
NAV = (500 − 20) ÷ 48 = 480 ÷ 48 = ₹10.00 per unit
4.2 Investor Return (%)
Formula:
Return = (Exit NAV − Entry NAV + Dividends) ÷ Entry NAV × 100%
Detailed Example:
- Entry NAV = ₹15.00
- Exit NAV after 1 year = ₹17.50
- Dividend distributed = ₹0.50
Return = (17.50 − 15.00 + 0.50) ÷ 15.00 × 100% = 3.00 ÷ 15.00 × 100% = 20%
5. Derivatives
5.1 Futures Pricing (Cost of Carry)
Formula:
F = S × er × t
Detailed Example:
- Spot price S = ₹2,000
- Risk-free rate r = 8% p.a.
- Time t = 6 months = 0.5 year
F = 2,000 × e0.08×0.5 = 2,000 × e0.04
e0.04 ≈ 1.0408 → F ≈ 2,000 × 1.0408 = ₹2,081.60
5.2 Options (Conceptual: Black–Scholes Inputs)
Inputs Needed:
- Current stock price (S)
- Strike price (K)
- Time to expiration (T)
- Volatility (σ)
- Risk-free rate (r)
These feed into N(d₁), N(d₂) to produce call/put values. Implementation uses statistical tables or software.
5.3 Hedging with Futures
Formula for Number of Contracts:
n = (Value of Portfolio × β) ÷ (Futures Contract Size)
Detailed Example:
- Portfolio value = ₹20 Cr
- Portfolio beta β = 1.1
- Each futures contract covers ₹2 Lakh
n = (20 Cr × 1.1) ÷ 2 Lakh = 22 Cr ÷ 2 Lakh = 110 contracts
6. Risk Management
6.1 Value at Risk (VaR)
Formula:
VaR = Portfolio Value × σ × Zα × √t
Detailed Example:
- Portfolio value = ₹10 Cr
- Daily standard deviation σ ≈ 1.5% = 0.015
- Z99% = 2.33
- Time horizon t = 1 day
VaR = 10 Cr × 0.015 × 2.33 × √1 = 10 Cr × 0.015 × 2.33 ≈ ₹3.50 Lakh
Interpretation: With 99% confidence, you will not lose more than ₹3.50 L on one day.
7. Interest Rate Derivatives
7.1 Interest Rate Futures
Formula:
Gain/Loss = (Sell Price − Buy Price) × Notional × Contracts
Detailed Example:
- Sell at 98.50, buy back at 98.00
- Notional = ₹2 Lakh per contract
- Contracts = 5
Price change = 98.50 − 98.00 = 0.50 points = 0.50% of notional
Gain per contract = 0.005 × 2 Lakh = ₹1,000
Total gain = 1,000 × 5 = ₹5,000
7.2 Forward Rate Agreement (FRA)
Detailed Example:
Company A wants to borrow ₹5 Cr in 6 months for 6 months. FRA rate locked at 7%.
If 6-month LIBOR in 6 months turns out to be 8%, FRA seller pays A the difference on ₹5 Cr.
Difference = (8% − 7%) × (5 Cr) × (180/360) = 1% × 5 Cr × 0.5 = ₹2.5 Lakh
8. Foreign Exchange Management
8.1 Forward Premium / Discount
Formula:
Premium/Discount (%) = (F − S) ÷ S × (12 ÷ Months) × 100
Detailed Example:
- Spot USD/INR S = 75.00
- 3-month forward F = 76.20
- Months = 3
Premium = (76.20 − 75.00) ÷ 75.00 × (12 ÷ 3) × 100
= 1.20 ÷ 75.00 × 4 × 100
= 0.016 × 4 × 100 = 6.40%
8.2 Money Market Hedge
Detailed Example:
Import payables USD 100,000 due in 3 months. USD deposit rate = 2%, INR deposit rate = 6%.
- Borrow PV of USD = 100,000 ÷ (1 + 0.02×3/12) = 100,000 ÷ 1.005 = USD 99,502.
- Convert USD 99,502 to INR at spot 75.00 = ₹7,462,650.
- Invest ₹7,462,650 at 6% p.a. for 3 months = × (1 + 0.06×3/12) = ₹7,574,900.
- Use ₹7,574,900 to repay INR loan; USD loan repaid from payables.
9. International Financial Management
9.1 Net Present Value in Home Currency
Detailed Example:
Project generates USD 200,000 annually for 3 years. USD/INR spot = 70. Discount rates: USD WACC=10%, INR WACC=12%.
- Year 1 PV USD = 200,000 ÷ 1.10 = 181,818 → in INR = 181,818 × 70 = ₹12,727,260
- Year 2 PV USD = 200,000 ÷ 1.10² = 165,289 → in INR = 165,289 × 70 = ₹11,570,230
- Year 3 PV USD = 200,000 ÷ 1.10³ = 150,262 → in INR = 150,262 × 70 = ₹10,518,340
- Total PV = ₹12,727,260 + ₹11,570,230 + ₹10,518,340 = ₹34,815,830
9.2 Interest Rate Parity (IRP)
Formula:
Forward Rate = Spot × (1 + i_domestic) ÷ (1 + i_foreign)
Detailed Example:
- Spot USD/INR = 70.00
- Indian interest rate = 8%; US interest rate = 2%
- Period = 1 year
Forward = 70 × (1 + 0.08) ÷ (1 + 0.02)
= 70 × 1.08 ÷ 1.02
= 70 × 1.0588 = ₹74.12