Required return - tax, inflation etc. (add or multiply?)

I have come across questions where sometimes it adds and sometimes it multiplies.

Can I be safe and multiply all the time?

i.e (1+r)(1+t)(1+inflation)-1

I’d rather keep it standard and not think when is it safe to add vs multiply… what is everyone’s thoughts?


The only concerns I have is if CFAI guideline answers have added, what would be grader’s action?

Both calculations are OK and you should get the points.

During the Schweser 3 day review, we were told to add for individuals and multiply for institutional investors. It appears that both will be fine on exam day based on prior mocks though.

See insti portfolio is larger size, hence even few decimal percentage higher matter a most, so use multiplicativa for insti, no harm to do the same for individual as well if you are more comfortable.

Multiply when in doubt is my best answer.