Öz
In a market that is inefficient in a weak form, some investors can benefit from past price movements through technical analysis and gain returns above the market average. The Efficient Market Hypothesis argues that the future values of financial asset prices cannot be predicted, and an above-average gain cannot be achieved by using past period information, including publicly disclosed information and non-public information. For this reason, which markets are efficient has become a research subject for investors and researchers. In this study, the weak form efficiencies of the metal commodity markets are investigated using daily dollar-based closing prices of gold, silver, platinum, and palladium for the period 4 January 2010 – 31 December 2021. In the paper, first of all, whether the series is linear or not was examined by Harvey et al. (2008) linearity test. Afterward, the unit root analysis of the series was performed with the Fourier ADF test, which considers structural breaks and multiple smooth transitions. Findings showed that gold, platinum and palladium markets have weak form efficiency, silver market is not. Accordingly, since the prices in gold, platinum and palladium markets move randomly it would be meaningless to make market timing in these markets. In the silver markets, price movements are not random and tend to turn to the average. Thus, investors trading in this market should prefer to make short-term trading based on past price behavior.