It might seem trivial to you, but when calculating FCFF starting from NI, why do we add back interest * ( 1- tax rate), but add back depreciation in full, rather than depreciation * (1 - tax rate)? Thank you!
You need to add back depreciation instead of depreciation*(1-tax) so as to take into account the tax benefit due to depreciation whi is depreciation*taxes in case you add back depreciation*(1-tax) then you are not taking into account the tax savings as a result of depreciation.
Assuming that you have a job, you get cash flow net of taxes, and you decide what to do with it: you can pay your mortgage, buy groceries, bribe government officials, buy a Maserati, whatever. Or not. Those are all uses of your free cash flow.
A company has free cash flow: the cash it gets from operations, net of taxes, less what it has to spend to keep the company going at its current size (FCInv). The company can decide what to do with that cash: it can pay off debt, pay dividends, pay interest on existing debt, purchase a new patent, whatever. Or not. Those are all uses of the company’s free cash flow (to the firm).