The volatility, according to Goldman Sachs' note from economist Michael Hinds, means that investors using oil and other commodities to hedge against rising inflation can scale back their holdings to achieve the same level of cover. Should investors increase their oil holdings now? Goldman's commodities research team reckons that rising worldwide demand - especially in fast-developing countries like India - as well as discipline by Saudi Arabia-led Opec and the Russia-led non-Opec group in holding back production, will outweigh surging output from the US, Canada, Brazil and some other sources.