High-frequency traders systematically front-run retail investors using speed advantages -- 'The stock market is rigged'

When Michael Lewis published "Flash Boys" in 2014, he introduced millions of Americans to a problem most didn't know existed: the stock market wasn't operating on a level playing field. At the heart of his investigation was a simple but troubling premise—that high-frequency trading firms with superior technology were systematically profiting at the expense of ordinary investors, executing what amounted to legalized front-running.

The claim seemed outrageous on its face. Brad Katsuyama, a former Royal Bank of Canada trader who became the book's central figure, had documented something peculiar: whenever he tried to execute large trades, prices would move against him almost instantaneously, before his orders could even complete. It was as if someone knew what he was about to do and got there first. That someone was high-frequency traders operating on microsecond advantages—firms spending billions of dollars to shave milliseconds off their execution times through fiber optic cables and sophisticated algorithms.

Industry defenders initially dismissed the allegations as misunderstanding how markets work. They argued that HFT provides liquidity and tighter spreads for all investors. The financial establishment largely circled the wagons, with major exchanges and trading firms insisting their practices were entirely legal and beneficial to the market ecosystem. Regulators, they suggested, had nothing to worry about.

But the evidence proved harder to ignore. The 2010 Flash Crash provided the most dramatic illustration of what could go wrong. On May 6, 2010, the Dow Jones Industrial Average plummeted roughly 1,000 points in minutes before recovering almost as quickly—a vivid demonstration of how HFT algorithms could move markets in ways that had nothing to do with underlying economic reality. The event shocked Washington and Wall Street alike.

What followed were investigations by the Department of Justice, the Federal Bureau of Investigation, the Securities and Exchange Commission, and the Commodity Futures Trading Commission. These weren't amateur inquiries—they were serious regulatory bodies taking seriously the possibility that the market infrastructure itself had been compromised. Academics at the Michigan Law Review and elsewhere began publishing peer-reviewed research documenting the mechanics of how HFT firms exploited their speed advantages.