The Korean won posted its strongest monthly gain against the U.S. dollar last month since March 2009, fueling optimism that the currency could strengthen below 1,400 won per dollar. This marks a sharp reversal from just weeks earlier when markets were bracing for the currency to weaken toward the 1,600 won-per-dollar level. Analysts said Sunday that the rebound was fueled by an improving dollar supply, as SK hynix converted part of the proceeds from its American depositary receipt (ADR) Nasdaq offering into won, while exporters stepped up dollar sales. In the Seoul foreign exchange market, the won ended onshore trading at 1,424.0 per dollar on Friday, the last trading day of July. The currency strengthened by 125.4 won against the dollar in July, an improvement from its June 30 close of 1,549.4 won, gaining 8.81 percent against the dollar. This marks its strongest monthly performance since March 2009, when the won strengthened by 150.5 won against the dollar during heightened volatility from the global financial crisis. The won weakened to as low as 1,559.2 per dollar on July 1, briefly