The first one is correct.
The second one might be correct, depending on what the vignette tells you.
But this https://www.analystforum.com/forums/cfa-forums/cfa-level-iii-forum/91371100 states that the second is correct.
- after tax nominal = (before tax real + inflation)(1-tax rate) = before tax real (1-tax rate) + inflation (1-tax rate) = after tax real + inflation (1-tax rate)
- after tax nominal = before tax real (1-tax rate) + inflation = after tax real + inflation
No, it doesn’t.
It depends on what the vignette says. In particular, it depends on whether the return to cover inflation is taxable or not. Sometimes it is, and sometimes it isn’t.