These days global inventories of nickel are measured in hours of demand, rather than days or weeks. Prices remain near record highs, as demand for the metal is strong, while supply is being disrupted by mine worker strikes and technical hitches.

Two weeks ago, the London Metal Exchange intervened in the nickel market, which is volatile even in the quietest of times, to calm things down. It limited the price difference between cash and futures prices to $300 a day. It also suspended rules that require traders with long positions, those betting on rising prices, to lend metal to short sellers who need to settle trades. This was a lucrative trade before the LME stepped in as nickel lending rates were more than $1,000 per tonne per day in early August.