I'm looking to add something to my investment portfolio for diversification. Right now, I own mostly a U.S. stock index fund, with a little bit of an international stock index fund, bonds and cash for diversification. I'm looking for something with the following attributes:
High-risk, high-reward, comparable to a diversified stock portfolio or maybe even riskier. It seems like anything considered safe is yielding practically nothing nowadays, and I have a long enough time horizon to tolerate some risk if it can be justified by higher expected returns and better diversification.
Generally performs well over long time horizons if you buy-and-hold.
Not strongly correlated to the health of the U.S. economy. Will not tend to rise and fall at the same time as broadly diversified stock portfolios. International stock is becoming less and less useful for this because as the economy becomes more globalized, U.S. and international stock tend to rise and fall at the same time.
Not gold. I think gold is a bubble and wouldn't touch it with a 10 foot pole at these prices.
How can I go about discovering an investment that meets my criteria?