As a large European country, Spain has a fair number of forex & CFD brokers with registered offices on its territory. This obviously also includes some brokers that offer the MetaTrader 4 (MT4) as one of their trading platforms. Given that this platform is so widely known, many brokers choose to stick with it just to make it easier for traders to migrate over from other brokerages.
All forex brokers with a physical presence in Spain are required to be regulated by both the Spanish Comision Nacional del Mercado de Valores (CNMV) and the EU-wide European Securities and Markets Authority (ESMA). This has many practical implications for traders, one of which is that trading leverage is limited to just 1:30 on the most liquid forex pairs, and even less on more volatile ones.