Revolutionary new data-driven techniques are transforming how banks manage their risk, but traders and quants working with the new system are worried that these innovations may be putting them at odds with a US ban on banks trading on their own account.

Dogged since the financial crisis by both the pressure to cut costs, and the merciless advances of technological innovation, banks have responded by creating a kind of HAL 9000-style supercomputer: an all-seeing, all-knowing electronic brain full of trading positions and data known as the central risk book.