Japan loses record $79.6bn of reserves after massive yen intervention

Japan’s foreign reserves suffered their largest monthly decline on record in August after the government carried out an unprecedented campaign of dollar selling and yen buying to halt the currency’s slide toward 40-year lows. Ministry of Finance data released on September 7 showed reserves falling by $79.575 billion to $1.2075 trillion at the end of August, compared with approximately $1.287 trillion one month earlier.

The 6.18% decline followed foreign-exchange intervention worth 15.4 trillion yen, approximately $98.66 billion, between July 30 and August 26. Reuters said this was Japan’s largest-ever intervention operation during a single monthly reporting period. The action initially helped lift the yen from levels close to 164 against the dollar to as strong as 155.20, although the currency later weakened again before recovering to roughly 155 to 156 in early September.

The scale of the operation has drawn particular attention because foreign securities, predominantly U.S. Treasuries accumulated during earlier episodes of dollar-buying intervention, account for around 70% of Japan’s reserve assets. Tokyo and Washington have responded to concerns over the sustainability of repeated large interventions by highlighting Japan’s access to a Federal Reserve liquidity facility that could provide dollars without requiring additional outright Treasury sales.

Why did Japan’s foreign reserves fall by a record $79.6 billion during August?

The simplest explanation is that Japan needed dollars to buy yen.

When the Ministry of Finance intervenes to strengthen its currency, it sells foreign assets or foreign currency and uses the proceeds to purchase yen in the market. A sufficiently large intervention therefore reduces reported foreign reserve holdings.

Japan’s official reserve assets stood at $1.207524 trillion at the end of August. Foreign-currency reserves accounted for $994.976 billion of that total, including $839.559 billion in securities and $155.417 billion in deposits with foreign central banks, the Bank for International Settlements and financial institutions.

The Ministry of Finance’s separate intervention figures show just how aggressive the campaign became. Tokyo spent 15.4 trillion yen between July 30 and August 26 as the yen approached historically weak levels.

The reserve decline was smaller in dollar terms than the headline intervention amount because changes in asset valuation, exchange rates and reserve composition also affect the monthly total.

Why was Tokyo willing to spend almost $99 billion supporting the yen?

Currency weakness had become an inflation and political problem rather than merely a market issue.

A weaker yen makes imported goods more expensive for Japanese households and businesses. That is particularly important for a country heavily dependent on imported energy and raw materials, and global oil prices are already elevated because of the Iran conflict and disruption around the Strait of Hormuz.

When the yen weakened toward 164 per dollar, officials faced the risk that imported inflation would accelerate even as the government considered fiscal measures intended to reduce pressure on household living costs.

The Ministry of Finance therefore intervened to slow what it viewed as disorderly depreciation.

Japanese authorities generally insist that intervention is aimed at excessive market moves rather than defending a permanent exchange-rate target. In practice, however, the size of the August operation shows that officials considered levels around the 160-164 region sufficiently destabilising to justify extraordinary action.

How effective was the intervention in strengthening the Japanese yen?

The initial market effect was substantial but not permanent.

Reuters said the yen strengthened from almost 164 per dollar to approximately 155.20 by August 3 after intervention began. That represented a major move for one of the world’s most heavily traded currencies.

The yen subsequently weakened toward 160 again before recovering to the 155-156 range by early September.

That pattern demonstrates the fundamental limitation of currency intervention. Governments can change market positioning and discourage speculative bets, but sustained exchange-rate trends are ultimately influenced by interest-rate differentials, inflation, economic growth and capital flows.

If investors can earn much higher yields on dollar assets than yen assets, selling dollars occasionally may not permanently reverse demand.

That is why expectations for Bank of Japan interest-rate policy are becoming increasingly important alongside the Ministry of Finance’s intervention strategy.

Why was U.S. participation in the yen intervention so unusual?

Part of the intervention was coordinated with the United States, Reuters reported, marking the first joint Japanese-American currency action since 2011.

That is politically significant because Washington generally avoids frequent intervention in foreign-exchange markets and has historically criticised countries it believes manipulate currencies for competitive advantage.

Supporting Japan’s yen-buying operation therefore signals that U.S. authorities also viewed the currency movement as unusually disorderly rather than simply reflecting legitimate market fundamentals.

The cooperation also strengthens the intervention’s psychological impact. Currency traders may be more reluctant to challenge Japan aggressively when they believe the U.S. Treasury and Federal Reserve are prepared to support stabilisation efforts.

Yet coordinated action cannot permanently replace domestic monetary-policy adjustment if large interest-rate gaps continue driving capital away from the yen.

Why could Japan’s U.S. Treasury holdings become part of the global bond-market story?

Foreign securities make up the largest portion of Japan’s reserves, and Reuters said those holdings consist largely of U.S. Treasuries accumulated during earlier periods when Tokyo was intervening in the opposite direction by buying dollars.

Selling significant quantities of Treasuries to obtain dollars creates a theoretical risk for U.S. bond markets if interventions become exceptionally large and frequent.

Japan remains one of the world’s largest foreign holders of U.S. government debt. Any perception that Tokyo might become a persistent seller can therefore influence Treasury-market sentiment, particularly during periods of already elevated U.S. yields.

This does not mean August’s intervention destabilised the Treasury market. Japan’s holdings are enormous, and transactions can be managed through different reserve assets and liquidity mechanisms.

The issue becomes more important if the yen returns to severe weakness and Tokyo needs to repeat interventions approaching $100 billion.

How does the Federal Reserve liquidity backstop reduce pressure on Japan’s reserves?

Tokyo and Washington have highlighted Japan’s access to a Federal Reserve facility created during the COVID-19 market crisis.

The mechanism allows major foreign monetary authorities to obtain dollar liquidity using U.S. Treasury securities as collateral rather than selling those securities outright. Reuters said officials have pointed to the facility as one way of demonstrating that Japan retains substantial capacity to obtain dollars even after the record intervention.

That could become valuable if future yen defence requires additional dollar liquidity.

Using a collateralised facility does not make intervention costless. Japan would still be taking financial and exchange-rate risk and would eventually need to unwind the transaction.

Its advantage is market stability. Tokyo can mobilise dollar resources without placing large blocks of Treasury securities directly into the market at a potentially difficult moment.

Could a Bank of Japan rate increase succeed where currency intervention has struggled?

Markets increasingly believe monetary policy may need to carry more of the burden.

The yen’s underlying weakness partly reflects the long period during which Japanese interest rates remained substantially below rates in the United States and other economies. Higher domestic rates reduce that gap and can make yen assets more attractive.

Expectations have consequently risen that the Bank of Japan could tighten policy again in September, particularly as imported inflation and currency weakness create additional pressure.

Rate increases come with their own risks. Japan has an enormous public debt burden, and higher yields can increase government financing costs while putting pressure on households and businesses.

The policy choice is therefore difficult: tolerate a weak yen and imported inflation, spend reserves defending the currency, or allow interest rates to rise more quickly.

August’s record intervention suggests Japan increasingly finds the first two options expensive.

What are the key takeaways from Japan’s record fall in foreign-exchange reserves?

• Japan’s foreign reserves fell by a record $79.575 billion during August to $1.207524 trillion.
• The monthly decline amounted to approximately 6.18%.
• Tokyo spent 15.4 trillion yen, around $98.66 billion, intervening in the currency market between July 30 and August 26.
• Reuters described the operation as Japan’s largest monthly foreign-exchange intervention on record.
• The yen initially strengthened from levels near 164 per dollar to approximately 155.20 before weakening again.
• Foreign securities, largely U.S. Treasury holdings, make up about 70% of Japan’s reserves and led the decline.
• Japan and the United States conducted part of the intervention jointly, their first coordinated currency action since 2011.
• Tokyo says access to a Federal Reserve dollar-liquidity facility gives it additional capacity without forcing large outright Treasury sales.

Can Japan keep spending reserves if the yen falls back toward 160 or 164 per dollar?

Japan clearly has enormous financial firepower remaining. More than $1.2 trillion in reserves means the country is nowhere near exhausting its ability to intervene.

The more difficult question is whether repeated intervention on this scale makes economic sense.

A $100 billion operation can punish speculative traders and stabilise disorderly markets, but if underlying interest-rate conditions continue weakening the yen, officials could find themselves repeatedly selling reserve assets to defend a currency level that markets keep testing.

That is why August may ultimately be remembered less for the record reserve decline than for what it says about Japan’s policy transition. Foreign-exchange intervention has bought time, but permanently reducing pressure on the yen may increasingly require monetary, fiscal and structural policy to work in the same direction.