This is an Accepted Manuscript of an article published by Taylor & Francis in Quantitative Finance vol. 19, no. 5, available online: https://www.tandfonline.com/doi/abs/10.1080/14697688.2018.1532101.We propose a new measure named the symbolic performance to better understand the structure of foreign exchange markets. Instead of considering currency pairs, we isolate a quantity that describes each currency’s position in the market, independent of a base currency. We apply the k-means++ clustering algorithm to analyze how the roles of currencies change over time, from reference status or minimal apprecia- tions and depreciations with respect to other currencies to large appreciations and depreciations. We show how different central bank interv...