It looks to me like nanotech would be a bad investment at the present time
(unless you use the term very broadly to include biotech and the like).
I don't even know what companies you would count as a nanotech investment.
But supposing you could find a startup somewhere that was claiming to
do R&D towards Drexlerian nanotech, with a payoff just a few years out,
this would be a very questionable investment.
The Idea Future (now called Foresight Exchange) market prediction of when
nano-scale robot arms and circuitry will come into being is around the year
2025 or so. So maybe in 20 years it will be a good investment, but not now.
John Walker of Autodesk, a successful CAD company, got interested in
nanotech and other Drexlerian ideas back in the 1980's. The company lost
a bundle on Xanadu, the Drexler-influenced hypertext publishing project.
(See Ed Regis' "Nano" for more on Drexler & Xanadu.) Eventually they
had to retrench and focus on their core business instead of these blue
sky ideas.
Nanotech is a good example of an area where Extropians are vulnerable to
being seduced by sexy sounding technology. We have to remain skeptical and
look at these ideas critically. Nanotech has a lot of potential but it's
not just around the corner.
Hal