All across Wall Street, humans are being replaced by computers. Even the people who make decisions about which stocks to buy and sell are being replaced by computer programs, by bots.
To understand what goes on inside a stock-picking bot, we at Planet Money built our own.
Bots are cheaper than stock-picking humans. They're less emotional and more disciplined. They can process more information at once. They are doing things like scanning social media for consumer trends and counting the number of cars parked in Wal-Mart parking lots, then using that to trade.