At this time, because of ZIRP, a money market sweep is worthless in terms of earning interest. https://en.wikipedia.org/wiki/Zero_interest-rate_policy https://e

At this time, because of ZIRP, a money market sweep is worthless in terms of earning interest. https://en.wikipedia.org/wiki/Zero_interest-rate_policy https://en.wikipedia.org/wiki/Zero_interest-rate_policy You are right that Schwab makes a pretty good profit from it. The way they do that is by lending "your" money to their margin customers and charging those people 7% or more while paying you pennies. In a "margin" brokerage account, "your" money is merely a debt obligation of Schwab. TD Ameritrade (and now I think Schwab) will sweep cash from your brokerage account into a real, genuine, bank account. But the interest rate is still almost nothing.