Yen Firms as BoJ December Hike Odds Rise, Testing the Limits of Japan's New Policy Framework

The yen strengthened Friday as traders added to bets that the Bank of Japan will raise rates again in December. USD/JPY last traded near 154, about 1.5 yen firmer on the day, leaving the pair down more than 3% from its early-October high near 158.5 and on track for its largest weekly gain since August.

The repricing has been steady rather than dramatic. Implied odds of a 10- to 15-basis-point hike at the December meeting have climbed above 55%, up from roughly 35% at the start of the month, as Tokyo-area CPI held above 2.5% and wage negotiations for next spring began with unusually firm early signals from major exporters.

"The BoJ's reaction function has finally become legible," said Aiko Tanaka, FX strategist at Sakura Markets Research. "It is not targeting a level for the yen. It is targeting the inflation outlook — and a weak yen that keeps import prices elevated is itself a reason to normalise faster."

The policy backdrop is more complex than the headlines suggest. Under its revised framework, the Bank has been gradually reducing government bond purchases and has kept the door open to further moves if core-core inflation stays above 2%. October's Summary of Opinions showed a more explicit discussion of the costs of an excessively weak yen than at any point in the past two years.

Global conditions have helped. Friday's cooler U.S. jobs report eased the front end of the Treasury curve, narrowing the rate differential that had been the yen's primary headwind. Japanese equities, however, finished lower as exporters absorbed the stronger currency and the Nikkei 225 gave back weekly gains.

The risk into December is two-sided. A surprise hike that markets are half-pricing is a recipe for a sharp USD/JPY move lower and continued pressure on Japanese equity exporters. A dovish hold would likely reopen the carry trade. For once, Tokyo's December calendar is as important to global FX as Frankfurt's or Washington's.