For decades, Japan stood as a quiet contradiction to mainstream economic theory. While other nations feared rising debts and bond market backlash, Japan kept borrowing and borrowing without suffering the consequences. Even as its public debt surged past 160% of GDP in 2020, the country continued to enjoy near-zero interest rates and relative market calm. To many policymakers around the world, Japan seemed to have cracked the code. But now, that illusion is crumbling.
In 2025, Japan’s long honeymoon with cheap debt appears to be ending.
It began slowly. In the wake of global inflationary pressures and changing central bank policies, government bond yields in Japan started to tick upward in 2022. At first, the movement was modest. But this year, the rise has become alarming.
Interest payments now consume about 10% of Japan’s central government budget a staggering figure for a country still grappling with sluggish growth and an ageing population.
still yet, the Bank of Japan (BOJ), once the bastion of economic calm, is paying out 0.4% of GDP in interest on the mountains of reserves it created through years of aggressive monetary easing. That’s money that ultimately comes out of taxpayers’ pockets.
Japan’s ultra-low interest rates were never just a quirk they were the foundation of its post-1990s economic policy. After the burst of its asset bubble in the early ’90s, Japan entered a long period of deflation and stagnation.
To cope, its central bank slashed rates and began one of the world’s earliest and largest experiments with quantitative easing (QE).
The BOJ bought up government bonds in bulk, effectively keeping interest rates at rock-bottom and ensuring the government could keep spending without immediate consequences. For a time, this strategy worked: it kept the economy from sliding into deeper recession, and the markets didn’t panic.
But every economic strategy comes with a shelf life.
Now, as inflation expectations rise and global interest rates normalize, Japan is being forced into a painful adjustment. Investors are demanding higher yields. The bond market once docile and predictable is waking up, and it’s not happy with what it sees.
Japan is not just another indebted country. It is the third-largest economy in the world, and its bond market is often seen as a barometer for global sovereign debt sentiment. If Japan begins to wobble, the rest of the world pays attention.
What’s truly worrying is that Japan’s fiscal vulnerability is not the result of one-off events. It is systemic. Decades of deficit spending, combined with a rapidly ageing population, shrinking workforce, and flat productivity growth, have painted the country into a corner. The political response? More spending, more handouts, and little appetite for structural reform.
This isn't just unsustainable. It's dangerous.
For years, economists in the U.S., Europe, and elsewhere pointed to Japan to argue that massive government debt didn’t necessarily lead to crisis. But Japan’s example may now be teaching a very different lesson: that delayed consequences are not the same as no consequences.
In a world where governments have grown comfortable borrowing at historically low costs, Japan is a flashing red warning light: interest rates don’t stay low forever, and when they rise, they do so quickly and without mercy.