Palladium futures tumbled, spurring the wildest price swings since late 2015 as investors turned sour on the precious metal. The commodity used mostly in auto catalysts has been a profitable trade as supply shortages boosted prices of near-term contracts. That gave investors the incentive to sell futures closer to delivery and buy those that are further along the curve as producers struggle to meet demand from carmakers. That incentive has narrowed this year as supply concerns ease.
