D.E. Shaw Group is known as one of the most successful quantitative investment funds, using computers to make trading decisions. This year, it is facing challenges replicating its success using human beings.

A group of D.E. Shaw traders who oversee about $2bn in bets for and against individual stocks have struggled to make money in 2018, people familiar with the matter said. They were down about $60m as of late September, these people said. By mid-October, the losses had deepened to roughly $100m, one of these people added.