I was watching a market ticker scroll past the other day — numbers flickering red and green faster than I could actually read them — when it hit me that somewhere in that blur, real money was changing hands between people who had never met, would never meet, and in most cases weren't even people at all. Just a "buy" and a "sell" button, and somehow, in less time than it takes to blink, millions of dollars had moved. I wanted to know what was actually happening in that gap, so I started looking into it. What I found was a system built almost entirely to hide its own complexity behind two deceptively simple buttons. The Button Doesn't Talk to Anyone You'd Expect The first thing that surprised me is that when you click "buy" on a trading app, your order almost never goes directly to a stock exchange. Instead, according to how brokers describe their own order-routing practices, your order is typically sent first to a market maker — a firm whose ent...



