Dollar Index. The US Dollar began rallying against all currencies in summer on the back of America's better growth outlook. It has now gained nearly 5% since mid-July compared to emerging market currencies and more than 6% against developed currencies. The Mexican Peso, Indonesian Rupee and Thai Baht have lost -8.2%, -5.6% and -5.1% respectively when compared to the Dollar. In contrast, China's Renminbi held up relatively well (-2.4%) and Poland's Zloty soared after the pro-EU opposition won parliamentary elections (+3.6%). Whilst among developed currencies, the Yen, Sterling, and Euro have lost -7.6%, -7.4% and -6%, respectively.