This year has seen two rounds of currency support measures totaling a record $170bn

The growing scale of currency interventions highlights the challenge governments face in influencing exchange rates amid rising cross-border capital flows. (Photo by Hazumu Urushiyama)

TOKYO -- Japan's currency authority spent a record 15.39 trillion yen ($96.5bn) to support its currency between July 30 and Aug. 26, Ministry of Finance data showed Friday, the largest amount in a single intervention round.