Unlever and levering for nonpublic company - why we dont use (1-t)

I thought the formula was supposed to use 1-t for the debt

At Level I they have (1 – t), but at Level II they don’t.

Thank your lucky stars that you’re at Level II where the formula is simpler (and makes more sense).

I thought project beta used 1-t…but this is for non-public company does it matter?

This is inconsistency, seems like level 2 authors are different from level 1

Please tell me more about this! It is so strange for me :frowning: Perhaps I’ve missed this knowledge!