Correlations pop up in the strangest places when markets misbehave. That much we know from the 1998 crisis and the blow-up at Long Term Capital Management. But each cycle spawns its own variation on the theme. Investors in Goldman Sachs’s quantitative fund, Global Equity Opportunities, have learnt this first hand after its sudden shocking fall in value. The good news for them is that Goldman is not standing on the sidelines. It is putting in about $2bn of equity and bringing in some friends for the ride, for a total of $3bn, compared with the fund’s value of $3.6bn prior to the investment.

Goldman reckons that dislocated markets offer opportunities and it has the capital to take advantage of them. But first, GEO has to be deleveraged. And before the fund plunges back into the market, investors will want to be sure its trading models have been stress-tested to breaking point.