The British investment bank said commodity indices had made "a complete recovery" from their mid-year lows, but investors had shifted from agriculture and precious metals to energy and base metals.

"This shift, along with the rise in prices, is reflective of constructive fundamentals in those markets," Barclays said, adding it believed the current strength in oil and copper was likely to wane in 2018.

"Although some suggest that the shifts in WTI and Brent futures curve structures are good indicators of the future path of prices, our analysis suggests otherwise."

It said total commodity investor AUM had risen for three consecutive months, by 4.8% to US$305 billion, driven primarily by rising commodity prices.