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Microlesson · 5-min read

Weighted Average Cost of Capital (WACC) — Fundamentals and Calculation

## Weighted Average Cost of Capital (WACC)

WACC is the blended cost of all capital, weighted by each source's share in the total.

WACC = Σ (Wᵢ × Kᵢ)

Weights must sum to 1.

### Tax Treatment by Source

SourceCostTax Adjustment
Equity sharesKeNone
Retained earningsKrNone
Preference sharesKpNone — dividends not deductible
Debentures / BondsI × (1–t) / NPYes — interest deductible
Term loansRate × (1–t)Yes

### Book Value (BV) vs Market Value (MV) Weights

BV weights: from balance sheet. Retained earnings shown separately.

MV weights: equity = shares × market price; debt = face × (market price/100). Retained earnings are not listed separately — they are already embedded in the equity market price.

MV weights are theoretically preferred for investment decisions — they reflect current investor expectations.

### Step-by-Step Process

1. Compute Ke (Gordon/CAPM), Kp (approximation), Kd (after-tax)

2. Determine weights (BV or MV as specified)

3. Multiply cost × weight for each source

4. Sum all products

Worked example

### Example 1

Q37 — WACC using MV weights (PYQ)

Capital: 2,00,000 equity shares at MV ₹30; 12% Pref ₹10L; 9% Deb ₹30L. Tax = 40%. D₁ = ₹3; g = 7%.

MV of equity = 2,00,000 × 30 = ₹60L

MV total = 60 + 10 + 30 = ₹100L

Ke = 3/30 + 7% = 10% + 7% = 17%

Kp = 12%

Kd = 9% × (1 – 0.40) = 5.4%

WACC = (60/100)×17 + (10/100)×12 + (30/100)×5.4

= 10.2 + 1.2 + 1.62 = 13.02%

### Example 2

Q38 — Current and revised WACC after new debt (PYQ)

Current: 6L shares × ₹600 MV = ₹3,600L equity; 12% Deb ₹180L; RE ₹120L (absorbed in equity MV). Tax = 30%.

Dividend = 24% × ₹100 FV = ₹24; g = 5%; D₁ = 24 × 1.05 = ₹25.20

Ke = 25.20/600 + 0.05 = 4.2% + 5% = 9.2%

Kd = 12% × 0.70 = 8.4%

Total MV = 3,600 + 180 = ₹3,780L

Current WACC = (3600/3780)×9.2 + (180/3780)×8.4

= 8.752 + 0.4 = 9.15%

New plan: ₹300L at 18% loan; MV of equity falls to ₹500/share

New equity MV = 6L × 500 = ₹3,000L; New Ke = 25.20/500 + 5% = 5.04% + 5% = 10.04%

New Kd_loan = 18% × 0.70 = 12.6%

Total MV = 3,000 + 180 + 300 = ₹3,480L

New WACC = (3000/3480)×10.04 + (180/3480)×8.4 + (300/3480)×12.6

= 8.655 + 0.434 + 1.086 = 10.18%

### Example 3

Q41 — WACC with multiple debt instruments (Study Material)

Equity ₹65L (Ke=16.30%); 12% Pref ₹12L; 15% Deb ₹20L; 10% Conv Deb ₹8L. Tax = 30%. Total = ₹105L.

Kp = 12%; Kd1 = 15%×0.70 = 10.5%; Kd2 = 10%×0.70 = 7.0%

WACC = (65/105)×16.30 + (12/105)×12 + (20/105)×10.5 + (8/105)×7

= 10.10 + 1.37 + 2.00 + 0.53 = 14.00%

### Example 4

Q40 — All-equity firm (Study Material)

Gamma Ltd: 5,00,000 shares at ex-div price ₹1.50; D₀ = 27 paise (constant, no growth)

Ke = 0.27/1.50 = 18%; No debt → WACC = 18%

⚠️ Common exam mistakes

  • Including retained earnings as a separate line when computing MV weights — market price already reflects retained profits.
  • Not applying the tax shield to debentures and term loans.
  • Using book value weights when market value weights are required (or vice versa) — read the question carefully.
  • Forgetting to compute component costs individually before building the WACC table.
Reference:
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