In March 2010, Axa Rosenberg the California-based quantitative equity manager owned by French insurer Axa, disclosed it had suffered its worst nightmare – a programming glitch in its investment process.

It cost Barr Rosenberg, the firm's co-founder, his job and a lifetime industry ban. The firm was fined $25m by US market regulator the Securities and Exchange Commission for failing to disclose the error to clients, and was ordered to repay their $217m losses. It was a severe blow to the firm's reputation.