(Bloomberg) -- The slump in the yen spurred by the latest Bank of Japan decision drove the currency to its weakest level since just after the collapse of Lehman Brothers Holdings Inc. in 2008.

The euro-yen cross rate rose as much as 1.8% to 150.43, a level last seen in September that year, as the Japanese currency dived on Friday against all of its major developed market peers. It was down as much as 1.9% versus the dollar, reaching 136.56 per greenback.

The move came after new BOJ Governor Kazuo Ueda prepared the ground for taking a more flexible stance on policy, scrapping the central bank’s guidance on future interest rate levels while keeping its main stimulus measures unchanged. 

The central bank maintained its rock-bottom interest rate and asset purchase settings at the end of a two-day gathering Friday. That was the result expected by almost 90% of economists surveyed by Bloomberg. 

The BOJ also announced it will hold a policy review of the “various monetary easing measures” that it’s taken since 1998 when the economy fell into deflation. That review is expected to take between a year and 18 months to report.

The outcome proved a disappointment for traders who might have been betting on a hint that the BOJ was planning to shift toward a more hawkish stance, adding downward pressure on the yen. One-month risk reversals jumped the most since June after the decision as traders unwound bullish yen bets. 

The Japanese currency fell to its lowest level since 1979 versus the Swiss franc, tumbling nearly 2%. The franc is seen as an alternative haven to the greenback amid uncertainty about US debt-ceiling negotiations, health of the banking industry and the impact of the most aggressive Fed hiking cycle in decades. The US central bank is set to meet on May 2-3.

Faster-than-expected inflation readings earlier in the day added to angst around the Japanese policy picture. With the central bank lowering its growth forecasts and upping its inflation expectations for this quarter, the specter of stagflation is potentially coming onto the radar for some investors. 

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