ON FRIDAY, MARCH 23, A GROUP OF SENIOR MANAGERS and software developers gathered around a cluster of plain gray desks on the open ground floor of exchange operator BATS Global Markets’ U.S. headquarters in Lenexa, Kansas. High on the facing wall, a grid of bright screens with customized, color-coded graphics — virtual dials and gauges on a vast electronic dashboard — displayed the speed, connectivity and data-processing capacity of the exchange’s trading infrastructure. But most of the executives below, including Chris Isaacson, BATS’s chief operating officer and top technologist, weren’t watching the gauges — they were looking at a single screen on one of the central trade desks and waiting for the launch of the company’s initial public offering on its own flagship trading platform, BATS BZX Exchange.

At 10:30 a.m., BATS began accepting pre-IPO auction orders. Isaacson and his team listened in as Cole Chmielewski, a trade desk specialist charged with handling the listing, discussed the auction’s progress with lead underwriter Morgan Stanley on an open line. Fifteen minutes later Morgan Stanley’s syndicate desk gave the signal: The order book had built correctly. The new issue was ready to go. The event marked the culmination of a year’s worth of complex coding work and months of rigorous testing. None of the BATS developers had ever run a corporate listings service before, and designing their own was a gutsy move. But Isaacson, 33, a self-reliant farmer’s son from Nebraska, was confident that BATS could pull it off.

His hopes....