Investors are moving out of their comfort zone for the first time in four years by allocating more of their portfolios into riskier assets, as confidence in the economy improves, a survey by Bank of America Merrill Lynch has found.

In the US bank's latest monthly fund manager survey, more investors said they were taking a higher level of risk by allocating cash to securities investments. It said "for the first time since January 2006, the survey shows investors are taking above average risk, relative to their benchmark".