Global fund managers are their most gloomy on the outlook for global growth and stock markets in two years as they adjust to a world of diminishing central bank stimulus, a survey showed on Tuesday.

The Bank of America-Merrill Lynch poll for October showed a sharp increase in money managers' risk aversion, with their equity allocation slashed to a 34 percent overweight from 47 percent in September.

That is the lowest in two years and mirrors the darkening economic environment: a net 32 percent of respondents think the world economy will strengthen over the next year, more than 20 percentage points down from September and also a two-year low.