The BofAML fund manager survey was conducted from July 2 to July 9, and the results reflect the weaker global economic outlook, particularly in China and Greece.
Among the 191 respondents – who hold a collective $510 billion in assets under management – 42% of investors said they expect the global economy to strengthen over next year, down from 55% a month ago.
As a result, cash levels jumped to 5.5%, the highest since December 2008, when the world was still in the midst of a major financial crisis sparked by the collapse of Lehman Brothers.
"When average cash balance rises above 4.5%, a contrarian buy signal is generated for equities. When the cash balance falls below 3.5% a contrarian sell signal is generated," BofAML Chief Investment Strategist Michael Hartnett said in a release.
The survey also showed the highest percentage of investors taking out protection against a fall in equities since February 2008.