Robinhood Instant's model doesn't actually require a customer to have settled funds to make that $300 purchase, so Robinhood has to pay for the $300 until the c

Robinhood Instant's model doesn't actually require a customer to have settled funds to make that $300 purchase, so Robinhood has to pay for the $300 until the customer's deposit clears. Separately, when someone with Robinhood Gold buys shares on margin, that purchase is financed in part with Robinhood's funds. Look up "initial margin" and "maintenance margin" to understand why. This involves some risk for Robinhood, because assets can sometimes lose value faster than Robinhood can sell them to preserve its equity. Finally, Robinhood is a clearing member and has to put up money as insurance to keep the clearinghouses capitalized in case some bad juju goes down in the markets and Robinhood hits the skids.