The loudest thing in global markets today isn't a stock — it's a currency. USD/JPY is at 155.85, down 1.80% on the day per Trading Economics, a second straight session of yen gains. FXStreet had the pair at 155.40, off 2.07% in late London hours — its weakest dollar reading in about a month. For a G10 pair, a 2% day is enormous.

Why it moved: the BoJ changed its own script

BoJ board member Hajime Takata, speaking in Sapporo on Sep 2, said 2026 is a “regime change” and the Bank should hike in a “nimble and data-dependent manner” instead of the market's assumed metronome of 25bp every six months — Trading Economics says he floated outsized or back-to-back hikes. Takata already dissented in July for 1.00% → 1.25%. Governor Kazuo Ueda added that policymakers must pay greater attention to upside price risks. Tokyo CPI ticked up to 1.9% in August from 1.8%, and the 10-year JGB yield is at 3.03%. Invezz notes prediction markets now put a hike at the Sep 17–18 meeting (BoJ's own calendar) at roughly 97.5%.

The second, separate leg is intervention. Traders think Tokyo ran a “rate check” during New York hours Wednesday — the usual dress rehearsal. Currency chief Atsushi Mimura said he's “neither at ease nor satisfied” with FX conditions and wouldn't confirm it. Two different catalysts, both pushing the same way: one is policy, one is the threat of the MoF's cheque book.

Who this actually hits

Look at Tokyo's own tape. The Nikkei 225 closed at 64,214, down just 0.17%, but the composition tells the story: Trading Economics reports Mitsubishi UFJ, Sumitomo Mitsui and Mizuho led gains — banks re-price loans off a JGB curve that keeps rising — while tech and exporters lagged, because a stronger yen shrinks the yen value of every dollar Toyota, Sony or Nintendo books overseas. The bigger exposure is offshore: the yen is the world's funding currency, and a fast yen rally is exactly how the August 2024 carry unwind began.

The one thing that flips it

The Fed meets Sep 15–16, two days before the BoJ. FXStreet cites CME FedWatch at about a 60% chance of a US hike. If the Fed goes and the BoJ then under-delivers on Sep 18, the rate gap reopens and this whole move unwinds — watch whether USD/JPY holds under 157 through Friday's US jobs print.

As of Sep 3, 2026, ~3:30pm ET / Sep 4, ~1:00am IST. Sources: Trading Economics, FXStreet, Invezz, Bank of Japan, Trading Economics (Nikkei). For discussion and education only — not investment advice. Verify before acting.