Friendship with benefits: Why Trump is helping Japan rescue the yen

The US and Japan jointly intervened to support the yen, driving it from nearly 164 to around 155.20 against the dollar.

Japan may have spent $36.58 billion buying yen during the operation, with the US Treasury reportedly selling euros to purchase yen.

This was the first coordinated US-Japan currency intervention since the 2011 earthquake and tsunami, and the first in almost three decades to strengthen the yen.

Japan is the largest foreign holder of US Treasuries, owning over $1.1 trillion, and the intervention aims to protect US Treasury markets and American exporters.

Japanese finance minister Satsuki Katayama confirmed Tokyo would not hesitate to conduct further joint intervention, while President Trump called it a 'signal of friendship' and beneficial for the world economy.