What are the most important characteristics to look for when choosing to invest in an ETF?

Question

Obviously past performance is no guarantee of future results. But what other characteristics can one rely one? I have a pretty good idea of how I'd like to diversify my portfolio, but am still trying to decide which funds in the various categories to choose from.

Answer 1

A small bid-ask spread.  That is usually the case if it is traded a lot.

Answer 2

This is very vague and has many factors, but I will do my best.  Basically, you want the ETFs holdings to go up.  If you invest in a Brazil ETF, you should have sufficient reason to believe that Brazil and its companies will continue grow.

Internal economic factors as well. If you think housing recovers, get a housing ETF.

ETF investing is really a hands-off strategy.  You should get a few broad-ranged and have decent exposure, but overall selecting a couple and leaving them alone is likely the best strategy (unless you trade them).

The SPY and a bit of Europe and emerging markets is a good portfolio (maybe some small caps in there too - IWM), but then again, you can do it all with a single global ETF (probably two for insurance), and just let it sit.  These will be very easy to track as well

Good luck.