CurrenciesDollar-buying fuels speculation over Tokyo's use of $1.3tn war chestInvestors are scrutinizing Japan's foreign reserves and intervention for clues on how much it may spend to stem the yen's decline against the dollar. (Photo by Akira Kodaka)June 5, 2026 10:55 JSTTOKYO (Reuters) -- Japan's foreign reserves fell by $77 billion in May, government data showed on Friday, as Tokyo resumed massive interventions to stem the yen's slide, fueling market speculation over how far it's willing to draw on its $1.3 trillion war chest.The reserves stood at $1.306 trillion at the end of May, down from $1.383 trillion a month earlier, according to the Ministry of Finance (MOF) data.The data on Japan's foreign reserves, the world's second largest after China, came a week after separate MOF figures showed that Japan spent 11.7 trillion yen ($73.13 billion) since late April to support the yen in what was the largest-ever intervention round in a month.Investors are scrutinizing Japan's foreign reserves and intervention records for clues on how much Japan might be able to spend to rein in the yen's sharp decline against the dollar.