Copper plunges on day of China's first onshore bond default. BOM is 2X short a base metals index equally split between copper, aluminum and zinc. This busted ETF sells for a 17% discount to NAV. If the herd comes back as they did in 2011, could be some nice upside if copper breaks $3 and BOM breaks $16 on the upside. BOS is the single short product, also sells at a discount, but volume is even smaller. BOS is the 20th best performing ETF as of Friday morning though, up 26% already this year thanks to the discount plunging from about 50%.
Chinese borrowers have used metals as collateral in order to obtain loans, but they have rehypothecated their metal several times over. There is the potential for major copper puke if China has even a mild financial crisis. The little cash crunch panic in June 2013 too copper to $3. ZeroHedge has coverage of the copper financing here: http://www.zerohedge.com/news/2014-03-07/copper-collapses-most-dec-2011-china-credit-fears