To understand this case, you need to meet the colorful cast of characters at its core: Chicago commodities traders. Meet part-time bookie, possible mob associate, and full-time trader Tony “T-Bun” Bonjourno. He’s a blue collar guy whose dad’s friend helped him get a job on the floor. Once there, T-Bun and his friends live a life beyond their wildest fantasies. T-Bun gives us our first glimpse of the FBI agents’ actions on the floor and tells an incredible story that might just be the answer...

When you picture the 1980s’ Wall Street boys’ club, you might not think of Chicago. But in 1987, its Mercantile Exchange dwarfed the New York Stock Exchange in both dollars and international influence. Member-owned and expanding rapidly, how it worked—or who was working it—was more obscured. That’s when the FBI stepped in. The Feds sought to shine light upon it through a high-stakes operation, the most expensive in its history, to expose corruption at Chicago’s Merc and Board of Trade. What...