Considering 30-days investment horizon, Petrobras Argentina SA is expected to under-perform the Eni SPA. In addition to that, Petrobras is 2.68 times more volatile than Eni SpA. It trades about -0.21 of its total potential returns per unit of risk. Eni SpA is currently generating about -0.37 per unit of volatility. If you would invest 4,482 in Eni SpA on April 26, 2012 and sell it today you would lose (546) from holding Eni SpA or give up 12.18% of portfolio value over 30 days.
Diversification
Significant diversification
Overlapping area represents amount of risk that can be diversified away by holding Petrobras Argentina SA and Eni SpA in the same portfolio (assuming nothing else is changed)