Brian Snyder/Reuters Bridgewater Associates, the world's largest hedge fund, is sounding the alarm on one crucial market driver, according to a note to clients reviewed by Business Insider. The hedge fund reportedly recently shifted to a net short position on US equities. On the surface, Bridgewater Associates' performance last month looks unremarkable. Sure, the $150 billion firm's flagship fund lost 1% in April, but it's still up about 4% over the first four months of the year, according to a Bloomberg report.See the rest of the story at Business InsiderNOW WATCH: What will probably happen with the North and South Korean peace treatySee Also:Bridgewater, the world's biggest hedge fund, says a crucial market driver is at 10 o'clock — and forecasts widespread pain once it gets to 12Hedge funds are making a dangerous bet — and history suggests it's going to blow up in their facesBANK OF AMERICA: There are 2 key levels everyone should be watching in the stock market right nowSEE ALSO: The stock market's recovery is one of the slowest on record — here's why that could be foreshadowing the next crash