Some facts about FOREX
The top-tier inter-bank market accounts for 53% of all transactions. After that there are usually smaller investment banks, followed by large multi-national corporations (which need to hedge risk and pay employees in different countries), large hedge funds, and even some of the retail forex market makers.
PCE - Personal Consumption Expenditure. BEA (Bureau of Economic Analysis); last day of each month, 8:30am EST, covers previous month data.