TOKYO - Few narratives spook Asia more than word of trouble in Thailand – even more so when foreign-exchange reserves are involved.

It was Bangkok’s devaluation in July 1997 that set in motion the Asian financial crisis. As foreign-exchange reserves ran out, the government and Bank of Thailand had no choice but to scrap the US dollar peg and drive the baht sharply lower.

Twenty-five years later, Southeast Asia’s second-biggest economy isn’t quite cascading toward a repeat of that meltdown. Yet Bangkok is again ground zero of something getting increasing attention in world markets: the speed with which developing Asia’s central banks are depleting their currency reserves.