But Hunsader argues that he’s seeing a small group of high speed traders who aren’t lying low. In fact, they’re taking advantage of the regular and predictable lull in the market to pop high speed trades in order to intentionally create a several hundred millisecond burst of volatility, and then execute follow-on trades to profit from that.

To understand what happens, you have to go inside just one second of trading and look at the way markets move at speeds that can be almost imperceptible to human beings.

On May 4, Hunsader says, he spotted those traders just before the April number was released. At 8:29:20 and about 200 milliseconds, he says, someone — he has no way of knowing who — executed a trade in the five year T-note futures market worth about $150 million.

A chart of that single second in the market shows that prices are relatively stable until the trade. And just after that, for the rest of the second, prices spike, and gyrate up and down as other automated high speed computers react to the trade.

Hunsader says he doesn’t know exactly how the traders make money off the volatility that they create, but he suspects they’re making other trades in the milliseconds following their market moving trade that take advantage of the relationships between this market and others that are impacted by it.

The traders that move first, and fastest, win, he says.

“It’s like two guys running in the woods, and they see a bear and one guy drops down and puts his shoes on and the other guy says, ‘what are you doing that for, you can’t outrun a bear,’” Hunsader says. “And the guy goes, ‘I don’t have to outrun the bear, I just have to outrun you.’”

On another occasion, Hunsader says he saw traders taking advantage of something as fundamental as the speed of light.

Because trades are executed by fiber-optic cable, the fastest they can travel—and the fastest anything in the universe can travel—is the speed of light. But even at that speed, it takes about 11 milliseconds for information from exchanges based in New York to get to exchanges based in Chicago. And that provides an opportunity for arbitrage for those who can move fast enough.