Rising government debt burdens, stubborn inflation pressures, and mounting geopolitical shocks are reviving concerns that major developed economies could be drifting toward a broader sovereign bond market crisis, according to economist Desmond Lachman.

Lachman, a former International Monetary Fund official now at the American Enterprise Institute, warned that the United States, parts of Europe, and Japan are simultaneously becoming vulnerable to investor backlash as deficits widen and borrowing costs climb.

“This would seem to set the country up for a government bond market crisis should foreigners come to believe that the US was on the way to inflate its way out of its debt problem or that the US could further weaponize financial policy,” Lachman said.

His warning comes as global bond markets are already showing signs of strain. Last week, yields on the 30-year U.S. Treasury bond climbed above 5% for the first time in nearly a year, reflecting growing unease over inflation, persistent fiscal deficits, and the possibility that central banks may be forced to keep interest rates elevated for longer than investors had previously anticipated.

The rise in long-dated yields matters because it increases borrowing costs across the economy, from mortgages and corporate loans to government financing itself. Lachman believes that the situation is especially dangerous because of the sheer scale of foreign ownership of U.S. government debt.

Foreign investors currently hold roughly $8.5 trillion in Treasury securities, creating what he views as a potential vulnerability if overseas holders begin to doubt Washington’s fiscal trajectory or become concerned that the United States could attempt to reduce its debt burden through inflation or financial pressure.

Those concerns are unfolding against a backdrop of growing geopolitical fragmentation. Countries such as China and Russia have already reduced portions of their exposure to U.S. Treasury holdings over recent years, while many governments are increasingly exploring alternatives to dollar-based financial systems amid concerns over sanctions and the expanding use of financial restrictions as geopolitical tools.

Inflation And War Pressures Unsettle Bond Markets

The latest anxiety surrounding bond markets is being amplified by the ongoing conflict involving Iran and its impact on global energy prices. Oil prices have surged in recent months as instability around the Strait of Hormuz disrupted shipping routes and intensified fears of prolonged supply constraints. Higher energy costs risk feeding broader inflation across advanced economies at a time when central banks had hoped price pressures were beginning to moderate.

Several major financial institutions have recently echoed concerns about a potential return to a structurally higher inflation environment. Analysts at JPMorgan Chase recently warned that sticky inflation could destabilize both stock and bond markets, drawing comparisons to the inflationary turmoil of the 1970s, when bond investors endured years of losses as interest rates climbed sharply.

Unlike previous cycles, however, governments now enter this period carrying historically large debt burdens accumulated after years of ultra-low interest rates, pandemic-era stimulus spending, and industrial policy expansion.

That combination creates a difficult balancing act. If inflation remains elevated, central banks may need to keep interest rates high, increasing debt-servicing costs for governments already running large deficits. But cutting rates too early could risk reigniting inflationary pressures and undermining investor confidence in sovereign debt markets.

Europe’s Fiscal Vulnerabilities Re-Emerge

Lachman argues that Europe may be especially exposed. During the eurozone debt crisis of the early 2010s, investor fears centered largely on smaller economies, including Greece, Portugal, and Ireland. Today, concerns are increasingly shifting toward much larger economies such as France, Italy, and the United Kingdom.

According to Lachman, all three countries now carry debt-to-GDP ratios above 100% while simultaneously running large fiscal deficits exceeding 5% of economic output.

“Three of Europe’s four largest economies are drowning in debt,” he said. “While in 2010 the Eurozone debt crisis was centered on Portugal, Ireland, Italy, Greece, and Spain, Today it is France, Italy, and the United Kingdom about which we need to be worried.”

That combination becomes more problematic in a higher-rate environment because governments must refinance maturing debt at significantly more expensive borrowing costs. The concern is not simply the size of debt, but the speed at which interest expenses themselves may begin consuming government budgets.

In Britain, fiscal pressures have intensified following years of weak productivity growth, elevated borrowing, and repeated economic shocks tied to energy markets and trade disruptions. France has also faced mounting scrutiny from investors and ratings agencies over spending levels and political resistance to fiscal tightening measures. Italy remains particularly vulnerable because of its massive debt stock and structurally slow economic growth.

Meanwhile, Japan represents perhaps the most extreme case globally. Its public debt burden has climbed to roughly 230% of GDP, among the highest in the developed world. While Japan avoided a crisis for years due to ultra-low interest rates and strong domestic ownership of government bonds, that stability is increasingly being tested as inflation rises and bond yields move higher.

Lachman noted that the yield on Japan’s 10-year government bond has climbed sharply from about 0.75% to 2.5%, its highest level in two decades. That increase is significant because Japan’s financial system has long been built around near-zero rates.

“With a public debt to GDP ratio of around 230 percent and an expected primary budget deficit, Japan appears to be well on the way to a bond market crisis,” he said.

Even modest yield increases can therefore have outsized consequences for government financing, banks, and pension systems.

Global Contagion Fears Grow

The broader concern is that sovereign bond markets are becoming increasingly interconnected at a time when fiscal pressures are rising simultaneously across multiple major economies. A disorderly selloff in one large government bond market could quickly spill into others through global financial institutions, currency markets, and investor positioning.

“The urgency of the need for such action is underlined by the fact that there appears to be government bond market problems brewing in each of these three major economies and that could have contagion effects should a bond market crisis occur in any of these economies,” Lachman stated.

That risk is particularly acute because government bonds traditionally function as the foundation of the global financial system and are widely treated as safe-haven assets. If investors begin demanding significantly higher compensation to hold sovereign debt, governments could face rapidly escalating refinancing costs while broader financial markets experience volatility.

The situation is also unfolding as central banks are gradually retreating from years of massive bond purchases conducted during quantitative easing programs. For much of the past decade, central banks effectively acted as stabilizing buyers of sovereign debt. As they reduce those holdings or slow reinvestment programs, private investors must absorb a greater share of government borrowing.

Lachman’s warning ultimately points to a deeper structural issue confronting advanced economies: many governments built fiscal models around the assumption that borrowing costs would remain permanently low. The combination of inflation shocks, geopolitical fragmentation, aging populations, energy insecurity, and rising defense spending is now simultaneously challenging that assumption across the United States, Europe, and Japan.