Four ways to weight capital

In the formula for the WACC:

${\text{WACC}}=W_{D}*C_{debt}+W_{E}*C_{equity}$

With: $W_{D}$ = Weight for debt $C_{debt}$ = Cost of Debt $W_{E}$ = Weigth for Equity $C_{equity}$ = Cost of Equity

There are for ways to determine weight for capital:

1. Book value
   1. ${\text{Market Value(Equity)}}={\text{Common Shares Outstanding}}*{P_{0}}$
2. Market value:
   1. ${\text{Market Value(Debt)}}$
3. Marginal weights
4. Target weights
   1. Based on ideal capital structure
   2. Single WACC based on that so called optimal structure