Forex is decentralized, so anything involving volume doesn't come from any central exchange. Exchange traded items like stocks and future can have real volume indicators. In forex, any volume indicator could be from one of several sources. These include: The broker's LPs. The broker itself (may be an aggregate of trades by the broker's clients or could just be some sort of estimate) Other - most likely some sort of estimate of calculation based on other data which hopefully allows an approximation of volume