Stocks around the world closed out one of their best years over the past decade, defying money managers who began 2019 expecting the bull market to be upended by threats from the U.S.-China trade fight and a slowdown in growth.

Just 12 months ago, the mood was far dimmer. The global economy was weakening, stocks, bonds and commodities were falling in tandem and money managers worried the Federal Reserve’s interest-rate increases would turn an economic slowdown into a protracted downturn.

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