Bridgewater Associates LP has bet more than $1 billion that stock markets around the world will fall by March, said people familiar with the matter.

The wager, assembled over a span of months and executed by a handful of Wall Street firms, including Goldman Sachs Group Inc. GS, -0.08% and Morgan Stanley MS, +0.92% , would pay off for the world’s biggest hedge fund if either the S&P 500 SPX, +1.59% or the Euro Stoxx 50 SX5P, -0.21% —or both—declines, some of the people said.