WSJ reporter Gunjan Banerji on how small investors are winning big

Retail investors may know something the pros don't. They're piling into AMC, which more than doubled this week, as well as GameStop, which is up more than 45%. Gunjan Banerji, reporter for the Wall Street Journal, joined "Squawk Box" on Friday to discuss her recent article about the retail trader and the power of momentum investing in the market.