Investors are weighing the durability of this year’s bull market in commodities amid warnings of more “frequent and violent price swings” from extreme shortages in base metals.

But brokers say the powerful rally that rocketed copper and gold to record levels will resume after metal prices were hit by profit-taking this week. Copper traded on the London Metal Exchange has since dropped 6 per cent from its record high on May 20 to $US10,159 a tonne.