The U.S. joins Japan in coordinated yen buying as both governments vow to intervene again if market volatility persists.

July 31 : The U.S. Treasury intervened to support the yen on Friday through outright purchases, the Financial Times reported, joining Japan in its efforts to boost the currency…

It was Washington's first yen-buying intervention with Tokyo in more than a decade as it languishes near 40-year lows.

Tokyo and Washington saw eye to eye on halting yen weakness