
Brokerage start-ups such as Robinhood, M1 Finance and SoFi are tiny compared with the trillions of dollars in brokerage assets at the likes of Schwab and Fidelity. But they've already made a big dent in the way things work: These small online brokers pioneered commission-free stock trading and fractional-share purchases, and now those services are standard fare at the bigger firms.
And that's one of the reasons we keep an eye on smaller brokerage firms – because they're shaking up the industry. If not for Robinhood, for instance, we might still be paying commissions on stock and ETF trades.