Yen Up Near 4% This Month: Why a Fed Hike Could Force BOJ's Hand

The yen’s four-week climb collides with the Federal Reserve’s Wednesday rate decision. The size of the Fed’s move could decide whether Tokyo’s currency gains hold or reverse.

The yen traded at 153.49 per dollar on Monday, just off the 152.89 seven-month high reached last week. Speculators turned net-long on the yen for the first time since February, marking a shift in positioning.

Why the Fed Comes First

Consumer prices in the U.S. accelerated in August, based on data released Friday. Traders now price Fed rate hike odds at 86% for Wednesday. That figure comes from the CME FedWatch tool, which estimates odds using futures pricing.

The Bank of Japan meets two days later, on Friday. MUFG analysts said a quarter-point hike is already largely priced into markets. However, the bank said the yen needs a signal of faster future hikes to strengthen further.

A different risk applies if the BOJ leaves further hikes off the table for October and December. TD Securities therefore said that scenario could send dollar/yen back toward the 157 to 160 zone.

The Stakes Reach Beyond Tokyo

Hedge funds have already adjusted carry trade positioning as the yen’s moves ripple beyond Tokyo.

The pressure extends beyond Tokyo as well. The U.S. dollar index held steady at 99.15 after two weeks of declines. Meanwhile, the European Central Bank raised rates last week, and the Bank of England is expected to hold Thursday. Yet that vote looks close.

James Athey, a fixed-income portfolio manager at Marlborough, described the stakes bluntly:

“Not hiking would be a catastrophic error. Not communicating robustly will be a significant own goal.”

Athey also pointed to repatriation flows and asset allocation shifts at GPIF, Japan’s giant public pension fund. Those forces are already pulling money back into the yen, separate from the rate decisions this week.

This month’s yen advance has almost reached 4%, adding to the pressure on Tokyo. Still, the bigger signal may come from Tokyo rather than Washington. Whether those gains hold depends less on the Fed’s Wednesday move than on the BOJ’s signal two days later.