The dollar slid against major currencies Monday as markets braced for potential US intervention in Japan's foreign exchange market. Investors worry such actions could undermine confidence in the world's primary reserve currency.

Recent speculation about coordinated currency intervention has pressured the greenback. Market participants fear Washington might join efforts to weaken the yen, which has surged following aggressive Bank of Japan policy shifts.

Traders are watching Treasury Secretary Janet Yellen's upcoming testimony for clues about US policy direction. Any indication of intervention could trigger broader dollar sell-offs. The currency's weakness reflects growing concerns about America's ability to manage global financial leadership amid rising geopolitical tensions and economic uncertainty.