His father worked in a car battery factory, while his mother, a trained teacher in Jamaica, became a seamstress for Mary Quant.

Founded in 2001 by Mr. Siegel, Mr. Overdeck and Mark Pickard, who has since retired, Two Sigma is one of a handful of “quant” firms, which apply a quantitative approach — the use of mathematical models rather than human decision-making to find patterns in historical data and other financial information — to trade stocks, bonds and more esoteric assets.

It put its name on an arena and celebrities in its ads; Bankman-Fried cultivated an image as a wild-haired savant, a former Wall Street quant who became a crypto luminary in the name of giving away his wealth to erase poverty and avert planetary destruction.

Up stepped Joseph Pimbley, a longtime financial consultant fluent in physics, software code, mathematics, and quant trades—kinda like SBF and his friends.

Bankman-Fried undoubtedly makes for the most compelling character in this story—a quick-thinking former Wall Street quant, always clad in cargo shorts and a T-shirt, who amassed a multibillion-dollar fortune before the age of 30, purportedly for the sake of giving it away for the greater good.