Every now and then I read that XWZ company is a brokerage firm and a clearing house. Well, in the country where I trade (Brazil), there is only one clearing house - CBLC - and it is a state owned company. I learnt that in US markets there are mutliple clearing houses and I got intrigued: how does it work? doesnt US markets have a central clearing house as well? Could someone make a brief explanation of how this model of multiple clearing houses work?