The global network of banks and large financial institutions that trade currencies directly with each other, forming the primary FX market.
The interbank market sets the true mid-market rate that retail spreads are quoted around. Participants include central banks, commercial banks, hedge funds, and large corporations. Minimum deal sizes typically start at USD 1 million.
Retail brokers aggregate interbank liquidity through prime brokers or liquidity aggregators and pass a version of those rates, plus margin, to retail clients.