The dollar posted its biggest gain in two weeks on Aug. 24, rising about 0.2% on the Bloomberg Dollar Spot Index after US Treasury Secretary Scott Bessent said Washington would pursue unprecedented sanctions to isolate Iran from the global financial system. He said countries trading with Iran could also face US sanctions, prompting renewed haven demand (buying perceived safer assets) and strengthening the dollar against all 10 Group-of-10 currencies. The move partly reversed losses linked to planned buybacks of long-term US government bonds, concerns about the US fiscal outlook and political uncertainty. Monex foreign-exchange trader Andrew Hazlitt said the warning refocused attention on the dollar’s dominant role in global trade. JPMorgan’s head of global macro research, Luis Oganes, said he was maintaining a neutral stance rather than pursuing further dollar weakness at current levels. The possibility that the Federal Reserve could still raise interest rates may provide additional support for the currency, although uncertainty remains over whether its rebound can last.