Trader and shipowner Trafigura Group has posted a big fall in earnings as oil markets shifted into backwardation in the first half.

Net profit was cut to $221.8m in the six months to 31 March, from $470.5m in 2017, despite revenue growing to $86.93bn from $67.31bn.

It said earnings were lower due to the "effects of challenging conditions in the oil market" that were only partly offset by a strong performance in non-ferrous metals and bulk minerals trading.