George Soros famously employed a global macro strategy when he sold pound sterling in 1992 at the time of the European Rate Mechanism debacle.
A major area of current interest in the global macro world is how to apply some of the new mathematical models coming out of quantitative finance to global macro. So far only a few hedge funds have tried, and none have really succeeded. The only area in which success could be claimed is in 'black box trading/commodity trading advisors'. Any future work in this area is likely to look to involve areas of momentum trading work that has come out of the quantification of behavioural finance.
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