So as long as AMZN was >= 20% of your basket, then it was fairly valued. Sounds about right.
Yes. This has been extensively studied. Almost every investor who deployed new capital in the late 90s lost money on those investments.
> as long as AMZN was >= 20% of your basket
You’d have to torture causality to come up with a portfolio that would have made sense in the 90s and would have been 20%+ Amazon. It wasn’t even in the top 10 most valuable public companies by market cap [1].
[1] https://en.m.wikipedia.org/wiki/List_of_public_corporations_...
[1] https://data.bls.gov/cgi-bin/cpicalc.pl?cost1=1&year1=199901...
It's also worse case because it assumes you buy at the $107 peak. It didn't spend much time above $100...
and there's the rub, knowing, a priori, what the proper balance should be.