by Mallika Mitra The U.S. dollar is not having a good summer. Down around 9% from its March highs, the greenback looks like it’s on its way to having its worst month in nearly a decade. Sure, that might be bad if you were thinking of booking a vacation abroad, but it could actually be a good thing for your investment portfolio. First off, why is the dollar weakening? The currency was strong for a while, then the pandemic hit and the Fed cut short-term interest rates to near zero.