WACC, Market or Target?

Do you use the market or target weights when calculating Wacc? Or it depends? I remember reading in Corp fin you use market but then I remember reading elsewhere you use target weights. Anyone know?

What is your purpose?

I believe it follows this order from highest to lowest priority: 1. Target capital structure 2. Market value based capital structure 3. Book value based capital structure

Use target if it’s given. WACC should be forward-looking.