LONDON- Investors have the most pessimistic outlook on the global economy in a decade, Bank of America Merrill Lynch found in a survey, as Japan ousted the United States as the most popular equity region amid last week's dramatic stock market sell-off.

A net 38 percent of respondents expected the global economy to slow, the worst outlook on global growth since November 2008, in the poll carried out last week.

U.S. and Chinese tech stocks remained the "most crowded" trade for the ninth consecutive month, indicating the market was still concerned about the overwhelming popularity of big tech.

Trade war remained the biggest risk for investors, though they also said they were increasingly worried about quantitative tightening and a slowdown in China, the world's second-largest economy.

Investor allocation to U.S. equities fell 17 percentage points to a net 4 percent overweight as Wall Street suffered its biggest losses since February.

The survey was undertaken from Oct. 5 to 11 with 231 panelists managing $646 billion in total.

(Reporting by Helen Reid, Editing by Josephine Mason) ((Helen.Reid@thomsonreuters.com; +44 20 7542 0402;))