This study addresses the problem of causal price relationships of biofuels for an enhanced group of agricultural commodities to capture possible asymmetric causal effects. It investigates the long-run equilibrium and assumes that an adjustment process toward this equilibrium exists. The adjustment process can be non-linear, implying that we can identify critical thresholds that determine regions in the sample that once exceeded, price inter linkages may vary. The empirical results indicate that

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... there are commodity prices that have strong causal (asymmetric) relationship with biofuel energy prices.