> Robinhood is only a clearing broker that works with executing brokers to complete transactions. Citadel is an example of an executing broker.
What? No.
With respect to clearing, transferring stock from the seller to the buyer, there are clearing brokers and introducing brokers. Clearing brokers have a direct line to the clearinghouse. Robinhood is one of these. Introducing brokers use a clearing broker to clear.
With respect to execution, matching buyers and sellers, you have brokers (who represent clients) and market makers (who bet their own capital). Robinhood is a broker. It sells its order flow to market makers, of which Citadel Securities is a major one.