This paper examines two interrelated issues in commodity markets, namely,the cyclical relationship between stocks and commodities and the function ofcommodity and agribusiness indexes in portfolios. A high negativecorrelation has existed between stock and commodity prices over the past 140years. Moreover, the two markets have alternated in price leadership with29-32-year cycles. The recent price dominance in agricultural commoditiesstarted in 2000, a result supported by the empirical results of theportfolio allocation analysis. For a risk-averse investor, irrespective ofthe period analyzed, placing funds in agribusiness and/or agriculturalcommodity indexes was sound investing.