I own a particular security. How can I find another security, which has uncorrelated or negatively correlated (anti correlated) returns with the one I already own? I would like both securities to have positive historic returns.
For example: TLT has a negative correlation with SPY.
EDIT: http://www.market-topology.com/correlation/ is actually very close to what I was looking for. However, it doesn't have certain preferred stocks. It looks like the correlation is computed based on the last 12 months.