The top performing precious metal of 2014 is beginning to come under pressure.

Since reaching its highest level in almost 14 years three weeks ago, palladium, used in catalytic converters that clean car exhausts, has dropped more than 4 per cent. It fell as much as 0.9 per cent to $835.90 a troy ounce on Wednesday, underperforming sister metal platinum as well as gold and silver.

Analysts say there is no fundamental reason for the recent weakness other than profit-taking by investors who have built large positions in palladium, a byproduct metal produced from platinum and nickel mines.