Short bets against the Japanese yen held by hedge funds have reached the second highest level ever seen, even as the currency has fallen to 34-year lows against the US dollar, according to a report by Reuters.

The yen has slumped by 11% so far this year to 160.00 per dollar, a level last seen in 1990. The report cites Commodity Futures Trading Commission data — which is now probably already out of date — in revealing that speculators hold the second largest net short yen position since the launch of yen future contracts in 1986.

The latest CFTC figures are for the week ended 23 April. With the yen since having fallen a further 3%, it follows that the yen short position for the weekend ended 30 April will have increased, possibly to a new record high.