Aluminium retreated from a 20-month high as investors booked profits and on expectations that its prolonged rally will be brought to a halt by increasing supply.

Benchmark aluminium on the London Metal Exchange closed 0.5 per cent lower at $US1,826 a tonne, after it touched the May 2015 high of $US1,835 in the previous session. Aluminium rose 12 per cent in 2016 as the market tightened, but analysts expect prices to come under pressure from higher…