Investors identified the U.S. fiscal cliff as the “top tail risk” in a September survey, according to Bank of America Merrill Lynch.

Thirty-five percent of global investors listed the so-called fiscal cliff, which may prompt more than $600 billion in spending cuts and tax increases unless Congress acts, as the biggest risk. That exceeds the 33 percent who are most concerned with Europe’s sovereign-debt crisis, according to the BofA Merrill Lynch Fund Manager Survey for September.

Pessimism about Europe is fading, with asset allocators taking an overweight position in eurozone equities for the first time since February 2011, the bank said in a report.