
With oil prices up 59% from their mid-February lows and both the S&P 500 and Hang Seng indices up somewhere around 15%-17% since then, we wondered if—and how tightly—both indices are performing together. Running 50-day correlations would also test whether the same close relationship still exists for the S&P 500 relative to commonly quoted commodities such as oil and copper. In relation to China’s main index the S&P 500 has continued to walk side by side, with the 50-day correlation still near 0.95. Curiously, for many years copper prices were considered a reliable indicator of China’s economic strength (and stock