Morgan Stanley’s Stephen Len is obviously on the same page as I am about how the rising interest rate differential between Europe and the US is likely to drive short term currency movements:
Policy rate differentials are especially important now for the currency markets, and it pays to focus on central banks these days.
Reason 1. Global monetary paths are diverging, not converging. Among the major economies, only the US has an output gap small enough to support tightening. I doubt either the ECB or BOE will be in a position to tighten rates this year. Many now understand quantitative easing must be terminated by early next year, but no one has proposed actually raising interest rates from zero. Therefore, monetary paths are diverging, with the rest of the world having trouble keeping up with the Fed. This makes the Fed much more important for the USD than in ‘normal’ times.
Reason 2. Global equity portfolios are likely to be out of balance. Since 2003, there have been massive equity flows into Euroland and Japan. Since much of these flows occurred when the USD was still in structural decline, and some of the outflows reflected fears of a USD crash, it makes sense to suspect hedge ratios are quite low on these equity outflows. With the rise in the FFR and resilient dollar, the cost of running these currency exposures is increasingly unjustifiable. The equity market cap-weighted short-term interest rate differential between the US and the major markets is now around 180 bp, and still rising. If the Fed takes the FFR to 5.0% by end-2006, the differential will reach levels last seen in 2000.