Charles Schwab, Ally and others have come under fire recently for their use of cash sweeps in their free robo-platforms. The practice of holding significant portions of client portfolios in cash so that the firms can collect revenue on the interest in lieu of charging a fee is not illegal, but the ethics are blurry. The large cash positions deprive clients of potential gains from the market, and many clients don't understand the mechanisms. David Goldstone from Backend Benchmarking and Laura Varas from Hearts & Wallets join Sean to break it down