The Baltic Dry Index (BDI) is a number (in USD) issued daily by the London-based Baltic Exchange. Not restricted to Baltic Sea countries, the index provides "an assessment of the price of moving the major raw materials by sea. Taking in 23 shipping routes measured on a time charter basis, the index covers Handysize, Supramax, Panamax, and Capesize dry bulkcarriers carrying a range of commodities including coal, iron ore and grain."

In 1744, the Virginia and Maryland coffee house in Thread needle Street, London, changed its name to Virginia and Baltick, to more accurately describe the business interests of the merchants who gathered there. Today's Baltic Exchange has its roots in a committee of merchants formed in 1823 to regulate trading and formalize the exchange of securities on the premises, which by then had moved to the Antwerp Tavern.

Every working day, a panel of international shipbrokers submits their view of current freight cost on various routes to the Baltic Exchange. The routes are meant to be representative, i.e. large enough in volume to matter for the overall market.

These rate assessments are then weighted together to create both the overall BDI and the size specific Supramax, Panamax, and Capesize indices. The BDI factors in the four different sizes of oceangoing dry bulk transport vessels:[3]