patloc7

All major stock market indices within a particular country are correlated because they hold similar stocks. Furthermore, a country's health and wellness driven its economic, social and military policies impact its stock market indices they same way leading to correlation. As for correlation of market indices between countries, in short, the world is getting smaller and more fluid due to digitization. Economies across the world are more interdependent and tightly coupled. Therefore, if something happens to one economy, other connected economies will feel the effect as well, leading to their respective stock indices moving together in the same direction.

Generally speaking, commodities and stocks react in opposite way to interest rate trend. If long term interest rate is trending up due to inflation, then commodities prices tend to go up whereas stock prices generally is expected to decline. When long term interest rate declines, the opposite is true. John Murphy, Martin Pring and a few others have written about correlation among asset classes based upon economic cycle.