youbet said:
Rusty.... Nice analysis, thanks for the effort.
I had my own selfish motives, because all the hand-waving and algebraic analyses
are nice, but I thought the spreadsheet was a good sanity-check ... but thanks.
One question. Since the inflation component of the tips interest would be added to principal and compound at 2.375% + inflation, why add it to a money market and assume 1% + inflation? Minor detail, but..........
I'm not adding the inflation component to the MM fund; that can't be done in real life
anyhow. If you look at my numbers, I'm simply doing what the Treasury does, growing
the principal with inflation and paying out coupon * principal. I'm only putting the coupon
payment into the MM.
But for ISM, yes, I *am* putting the inflation component into the MM fund. Yes, I suppose
one could reinvest it, but not automatically and commission-free (theres's no DRIP, at
least at Schwab), so the hassle and commission wouldn't be worth it (to me) except maybe
one or a few times per year as you suggest. But it's not like anyone is going to take the
ISM interest and spend it on lottery tickets. I assume I'll invest it in something worthwhile,
where it'll compound - and that worthwhile thing may or may not be more ISM, depending
on its price and whatever else becomes available. So in looking at the total return of
ISM, I'm simply assuming something semi-reasonable is done with the interest, and the
conclusion (of ISM vs TIPS) is valid even if that reasonable use of that money isn't
putting back into more ISM. Make sense ?
Inflation + 1% seemed like a reasonable hack at MM rates. If you just fix them at
today's 5%, and if inflation is significantly higher than that, then TIPS and ISM will
perform equally (or TIPS may even be slightly ahead), I guess because it would really
be hurting you to just dump the ISM interest into the negative real-return MM fund.