New Delhi, Jan. 26 -- The dollar slumped to a four-month low on global foreign exchange markets Monday, linked in part to a surge in the yen that traders suggested could be a signal that authorities in Tokyo and Washington were preparing coordinated action to support the Japanese currency.

Reports said both the New York Federal Reserve, as well as Japan's Ministry of Finance, made so-called rate check calls to foreign exchange trading desks, during which they asked for live bid/ask levels for the dollar-yen currency pair.

Rate check calls are typically seen as a precursor to direct market intervention, a move which was floated again on Sunday by Japanese Prime Minister Sanae Takaichi, who told Japanese TV her government would "take nece...