Yet more reason to panic? The Baltic Dry index, which measures dry bulk shipping costs, plunged by nearly a quarter last week – 10 per cent on Friday alone – as rates plummeted for the biggest ocean carriers of raw materials. Shipping groups’ shares, notably in Asia, have followed suit. Given the index’s reputation as a leading indicator, that looks scary. In fact, the index’s predictive value has weakened as it has become far more volatile than the commodities markets underlying it, gyrating around on factors such as shipping supply bottlenecks. It has twice doubled and fallen back within 15 months; its latest slide leaves it 70 per cent below its May peak.