The Baltic Dry Index tracks the cost of shipping major raw materials (iron ore, coal, grain, cement, copper, sand and gravel, fertilizer and even plastic granules). Or, more simply, it tracks the precursors of economic output. As such, the Index provides a measurement of the volume of global trade at the earliest possible stage. The Index is down 48.4% in the last month, and 54.4% in the last three months.