Record global car sales will keep platinum and palladium in high demand and short supply for the third year in a row, according to forecasters.

The prediction marks the longest stretch of shortage for the metals, which are used as catalytic converters, since 2005 for platinum and 2000 for palladium. Platinum is expected to gain 13 percentage to average $1,635 an ounce by the fourth quarter of next year. Palladium is predicted to gain 10.3 percent to average $823 an ounce, its highest for a quarter since 2001.

Unlike gold and silver that have slumped 20 percent or more as investors lose faith in them as a commodity of value, the market is bullish on platinum and palladium. Although metal stockpiles are diminishing as mining companies have difficulties in keeping up with current demand, car sales growth is projected to increase to 4.8 percent in 2014 from 2.7 percent this year.

It is expected, however, that improving mine output will decrease shortages. The platinum deficit is projected to decline 59 percent to 239,000 ounces and that in palladium to narrow 16 percent to 686,000 ounces, according to Barclays. Primary supply will expand 0.4 percent for palladium and 2.1 percent for platinum, the bank says. Should mines be disrupted by strikes or natural disasters, there exist stockpiles that can be tapped. This year, about 80,000 ounces of platinum was lost to such events.