Currency intervention could temporarily strengthen the yen, but economists warn that Japan’s massive debt burden, suppressed bond yields and persistent capital outflows could eventually overwhelm efforts to support the currency.
Foreign exchange intervention may provide temporary support to the Japanese yen, but economists and market experts warn it is unlikely to reverse the currency’s longer-term depreciation unless Japan addresses the fiscal and bond-market pressures weighing on it.
At the heart of the problem are Japanese government bond yields, which remain low relative to yields in other major economies. The Bank of Japan’s continued presence in the government bond market has helped contain borrowing costs, but low yields also make Japanese assets less attractive to investors and encourage capital to move overseas.
This creates a difficult policy trade-off. Higher yields could support the yen by improving returns on Japanese assets, but a sharp increase in borrowing costs would put additional pressure on Japan’s enormous public debt burden.
Against this backdrop, some economists see a risk of USD/JPY eventually moving towards 180 if intervention fails to change the underlying dynamics driving the currency.
Why intervention may have limited impact
Economists broadly point to three conditions that can make foreign exchange intervention more effective: extremely stretched speculative positioning against a currency, significant undervaluation and monetary policy that supports the direction of intervention. Japan currently faces challenges on all three fronts.
While speculative short positions against the yen have been sizeable, they have not necessarily reached the extreme levels historically associated with major market reversals.
More from BusinessMeanwhile, the argument that the yen is heavily undervalued simply because it has weakened substantially over several years may overlook structural changes in Japan’s economy and financial markets.
A currency can remain weak for prolonged periods when underlying fundamentals shift. In Japan’s case, experts point to the interaction between government debt, suppressed bond yields and overseas capital flows as an important structural force behind yen depreciation.
Monetary policy also remains critical. Intervention becomes harder to sustain when interest-rate differentials continue to favour overseas assets.
Japan’s bond market holds the key
The bigger concern is whether Japanese government bond yields adequately reflect the fiscal risks associated with the country’s debt.
Some estimates suggest the theoretical or “shadow” yield on Japan’s 30-year government bond could be around 300 basis points higher than its prevailing yield if the impact of central bank support were removed.
Such a gap would suggest that Japan’s fiscal risk premium is being substantially suppressed. Low domestic yields encourage Japanese investors to seek higher returns overseas, generating capital outflows and creating persistent downward pressure on the yen.
This means currency intervention can disrupt speculative positions and trigger sharp short-term appreciation, but it cannot necessarily eliminate the fundamental incentive for capital to leave Japan.
Japan’s debt burden complicates the outlook
Japan’s primary fiscal deficit is not exceptionally large compared with some other major economies, but its accumulated government debt is far higher.
That distinction matters because allowing bond yields to rise significantly would increase debt-servicing costs and potentially intensify concerns about fiscal sustainability.
Japan therefore faces an uncomfortable policy equation: keeping yields low protects government finances but can weaken the yen, while allowing yields to rise could support the currency but increase fiscal pressure.
Economists say a more durable solution may therefore require action on the government balance sheet rather than repeated intervention in foreign exchange markets.
Japan owns substantial financial assets, meaning its net debt is considerably lower than its gross debt. Selling a portion of those assets and using the proceeds to reduce gross public debt could potentially improve investor confidence without requiring a dramatic increase in bond yields.
Without fiscal consolidation or a meaningful shift in Japan’s interest-rate dynamics, however, intervention-driven yen rallies could prove short-lived.
That leaves the risk of renewed depreciation firmly on the table — and, in a more bearish scenario, USD/JPY 180 could eventually come into view.
