How is "Investment Expense" calculated?

[drewb]

Hi everyone,

First, I just discovered FIRECalc and the forum and really like the tool =)

My issue: I'm having trouble understanding how the "Investing Expense" column is calculated in the "single-year" spreadsheet when I check the box to "provide data and formulas in spreadsheet format." My understanding is that this represents, for example, the 0.18% investment fee I'd pay to Vanguard, and I assumed each entry in this column would be 0.18% x the amount in "Starting Portfolio." However, when I do the above multiplication, I always get a number that is close to, but not quite, the number in "Investment Expense."

I tried multiplying 0.18% by other columns that seemed similar to "Starting Portfolio" in magnitude, but still couldn't get the numbers to match.

I've attached my "single-year" spreadsheet and I'm hoping someone can tell me how "Investment Expense" is calculated. I added a column to the right (column V) with 0.18% x the amount in "Starting Portfolio," and highlighted it and the "Investment Expense" column to show what I mean when I say that they're close but not the same.

Thanks, any clarification is appreciated!

Andrew

 

[pb4uski]

Just a guess that it would be based on the beginning of year portfolio less the annual withdrawal since I suspect that FIRECalc assumes that withdrawals occur at the beginning of the year.

 

[drewb]

Thanks @pb4uski for the idea!

I checked it out and unfortunately that doesn't seem to be it; for some years, 0.18% x starting portfolio > Investment Expense, and in other years 0.18% x starting portfolio < Investment Expense.