## Cost of Redeemable Debentures
Redeemable debentures are repaid at a specified future date. The cost must account for both the periodic after-tax interest payments and the capital gain or loss when the debenture is redeemed.
### Approximation (Short-cut) Formula
```
Kd = [I(1−t) + (RV − NP)/n] / [(RV + NP)/2]
```
Where:
- `I(1−t)` = Annual after-tax interest
- `RV` = Redemption value (what the company pays back)
- `NP` = Net proceeds at issue (or market price for existing debt)
- `n` = Remaining years to maturity
- `(RV − NP)/n` = Annual capital adjustment (amortised gain or loss)
- `(RV + NP)/2` = Average capital employed over the life
### YTM (IRR) Method
Find the rate `r` at which the PV of all cash outflows (after-tax interest + redemption) equals the current inflow (NP or MP):
```
NP = Σ [I(1−t) / (1+r)^t] + [RV / (1+r)^n]
```
Solve by trial and error, then interpolate:
```
Kd = RL + [(NPV at RL) / (NPV at RL − NPV at RH)] × (RH − RL)
```
### Reading the capital adjustment sign
- Issued at discount (NP < RV): gain on redemption → positive term → increases Kd
- Issued at premium (NP > RV): loss on redemption → negative term → decreases Kd
### Tax on capital gain/loss
In the standard Indian CA exam approach, the capital gain/(loss) on redemption is not separately tax-adjusted unless the question explicitly asks for it. Only the interest component gets the tax shield.