Stats › Currencies and commodities › FX intervention
When central banks intervene
Most central bank intervention happens in the dark. A desk buys or sells, the market guesses, and nobody confirms anything for months. Japan is the exception. The Ministry of Finance publishes the exact yen amount of every operation, monthly with a lag, and then daily one quarter later, in a spreadsheet going back to April 1991.
That makes this one of the very few places in FX where you can put a hard number on something everybody else is estimating. So this page is built around those numbers, with the Swiss National Bank's balance sheet, the European Central Bank's own intervention log and the New York Fed's quarterly reports layered on top.
Then the question everyone actually wants answered: does intervention work. I have gone to the BIS for that rather than to anyone with a position, and the answer is less flattering than the headlines suggest. Every figure below is linked at the bottom. Go and check them.
Japan's MOF publishes intervention to the day. The largest single day in the published record since 2010 is 31 Oct 2011 at ¥8,072.2bn. The 2022 episode was ¥2,838.2bn on 22 Sep and ¥6,349.9bn across Oct. The 2024 episode was ¥9,788.5bn in Apr and May, including a single day of ¥5,918.5bn on 29 Apr, plus ¥5,534.8bn on 11 and 12 Jul. Then nothing at all through the whole of 2025 and Q1 2026, followed by ¥11,734.9bn in the month to 27 May 2026, the largest monthly total in the released data. The SNB's balance sheet went from CHF 270bn at end 2010 to a peak above CHF 1 trillion. The ECB has intervened on just eight days since 1999. And the BIS survey answer on whether it works is: mostly under a month, and not much after.
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Below this point there are 11 sections, 2 charts, 2 tables and 10 named sources, roughly 3100 words of it. Every figure carries the source it came from and the date the data is from.
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