A strong global growth outlook lifted both industrial commodities and the stock market over the last year or so, but the close relationship between these two asset classes is breaking down. That’s illustrated in the chart below from Capital Economics, comparing the S&P GSCI commodity index with the S&P 500 SPX, -0.57% In a Thursday note, economist Tom Pugh pinned the divergence on geopolitical risks, which led to a surge in the prices of oil and some industrial metals. Aluminum prices soared 13% last week after the U.S. Treasury on April 6 slapped sanctions on Russian entities and individuals in response to what it said was Moscow’s attempt to “subvert Western democracies” and its pursuit of “malicious cyberactivities.” The sanctions included United Co. Rusal, which is responsible for 7% of global aluminum output. Aluminum prices continued to rise this week, with three-month prices hitting a more-than-six year high at $2,603 per metric ton. Nickel prices are also soaring, hitting their highest level since December 2014, on worries Russia producer Norlisk Nickel could also be caught up in the sanctions.via