This chapter is about understanding the role that commodity traders play in the world city network. Commodity trade is crucial in shaping economic globalization, both in the form of physical exchange of goods and in the form of financial transactions. Some older geographical thoughts on the role of traders and trade in shaping urban fortunes, most notably the work of James Vance (1970), are presented. These insights are confronted with a detailed overview of the contemporary practices of commodity traders in coordinating global supply chains and transactions, effectively linking various markets and places across time and space. The main hypothesis we induce is that in order for commodity traders to act as global agents they prefer the concentrated agglomeration benefits offered by (world) cities.