Revenue at the world’s 10 largest investment banks is on course to decline again in 2015 by two percent to $148 billion compared to a year ago, although a strong showing in equities will limit the fall, a survey on Tuesday showed. It follows a weak third quarter, when revenue slipped by 8 percent, the survey by industry analytics firm Coalition showed. Investment banking revenue has slumped in recent years, especially in Europe, as tougher regulations, litigation costs and market volatility have prompted banks to restructure, shedding staff and exiting certain business lines.