New regulations are leaving European institutions with little room to maneuver when it comes to finding ways to improve portfolio returns in a challenging investment market. The Continent's institutional investors have come under increasing pressure by historically low interest rates and the protracted debt crisis.To generate incremental returns, some European institutions plan to raise their investments in potentially higher-yielding assets such as corporate bonds, emerging market debt and high-yield fixed income as well as in alternative investments such as commodities and infrastructure.