TOKYO — The bond vigilantes are back — and now they’re patrolling every major debt market at once. As deficits balloon, spending runs unchecked and oil prices spike, investors are reasserting control over markets that once seemed shielded from shocks and sending yields skyrocketing.
The revolt spans the US, Japan, Europe and beyond as a deepening Iran war upends economic trajectories and markets alike. That’s refocused markets on a problem that fell off the radar over the last decade: sheer oversupply.
Global debt topped US$365 trillion in early 2026 — nearly seven times the combined economic output of the US and China, according to the Institute for International Finance. The timing is pointed, as US President Donald Trump and Chinese leader Xi Jinping staged a show of cooperation in Washington this week with very little in substance to show for it.
As Carlos Casanova, economist at Union Bancaire Privée, puts it: “The Trump-Xi summit extended the US-China trade truce by two months, but produced no major breakthroughs. The meeting was primarily focused on managing bilateral tensions, with AI competition, semiconductor controls, Chinese investment in the US and Taiwan remaining contentious issues.”
While Trump and Xi held talks that could’ve been an email, bond markets were sounding alarms about the chaotic global environment that both economies will encounter in 2026’s final stretch.
“Every major bond market’s feeling the heat at once,” says deVere Group CEO Nigel Green. “Anyone positioned for a global easing cycle has had the ground pulled from under them.”
Japan flashed the first warning, with 10-year yields hitting a 30-year high near 3%. This week, US Treasuries followed, with yields reaching levels unseen since 2007 — traders called it “Black Wednesday.” Thirty-year yields sit at 22-year highs; 10-year yields are at two-decade highs.
In Europe, French 10-year yields at 4.6% mark a new post-2008 financial crisis high. Yields in Greece and Italy have risen by similar magnitudes. Earlier this month, yields on Germany’s 30-year Bund surged totheir highest since 2011, around 3.84%.
Capital Economics’ John Higgins notes some see 5% on the US 10-year as a potential meltdown threshold — though he’s not convinced that’s the exact number; higher yields clearly threaten US fiscal sustainability and equities alike.
Verdence Capital’s Megan Horneman warns the whole Treasury curve is turning into a headwind for risk assets, potentially setting up “a pretty messy end of year” for stocks. “When you see violent moves in the Treasury market, something ends up cracking,” she said.
Not everyone’s alarmed, though. UBS Global Wealth Management still favors equity upside despite volatility from inflation, geopolitics, debt and AI-bubble fears. Yet Bank of America raised its year-end two-year yield forecast to 5%, with implications for credit across the $32 trillion US economy.
Things are likely even worse than the data show. IIF economist Emre Tiftik notes that higher inflation has helped contain debt ratios, masking underlying vulnerabilities.
Yet, he says, “as benchmark rates rise, interest expense is set to surge, while structural pressures from healthcare and public pension spending remain largely unaddressed.”
At the same time, mature-market governments now spend more on interest expense than the world invests in either artificial intelligence, defense or clean energy.
“The key question is what could trigger an inflection point in dollar demand,” Tiftik adds. “Episodes over the past year have tested the ‘debasement trade,’ yet US securities remained well bid despite heightened volatility and speculation, partly because alternative markets lack comparable depth and liquidity. However, as structural pressures—including heavy debt-service burdens—become more visible and binding, such episodes may become more frequent, and market reactions could be sharper and more abrupt.”
What’s clear is that government bond yields have recently “jumped in quite an alarming way,” says Robin Brooks, economist at the Brookings Institution.
Brookings argues that markets think central banks are behind the curve. The evidence: this week’s “wild rise in yields emanated out from the front end of the curve,” from the two-year end of the maturity spectrum. This pushed up everything out to the 10-year yield as inflation concerns heat up.
It’s clear, too, that high-debt countries are extremely vulnerable. “The exception to the pattern” whereby longer-term yields stayed anchored “doesn’t hold for high-debt places like France, Italy and Greece,” Brooks explains, noting that the rise in government yields across Group of 10 nations is alarming. It’s also worth noting, he says, that French yields are up even more than the US, which this year saw its national debt top $40 trillion.
All this has International Monetary Fund (IMF) chief Kristalina Georgieva saying it’s “impossible to stress strongly enough how critical it is” to bring down debt and prioritize fiscal consolidation.
“There are these two things that must be done: bring debt levels down, put fiscal consolidation as a priority, and make sure that the central banks deliver on their mandate for price stability,” she says. “It’s impossible to stress strongly enough how critical it is to get the courage to take the steps that are necessary. These are politically tough steps to take, but necessary steps to take.”
The OECD’s latest outlook similarly expects rising yields to force governments to rein in spending, boost efficiency and shore up revenue.
Stanford University economist Hanno Lustig argues post-2008 central bank policy obscured how much long-term debt governments were really taking on. In the decade after Lehman, central banks — the Fed, ECB, Bank of England, Bank of Japan — absorbed much of the new bond issuance themselves, effectively letting governments borrow at low policy rates rather than true market rates. That accelerated further during Covid-era stimulus.
2013 was a hinge point: the BOJ’s aggressive quantitative easing effectively capped 10-year JGB yields near zero, killing price discovery and putting a floor under Japanese bond prices.
Now, Allianz’s Mohamed El-Erian argues, markets face a perfect storm — inflation, stronger-than-expected US growth, Middle East tensions, a more hawkish Fed and AI-bubble anxiety — while investors remain psychologically anchored to the artificially low yields of the post-2008 era.
In a new analysis, Fitch advisory unit BMI points out that the rise in government bond yields in recent months “has renewed concerns that a tightening of financial conditions could ultimately slow economic activity. Higher market interest rates do not automatically translate into a credit crunch. Nevertheless, sustained increases in funding costs can lead banks to tighten lending standards and become more selective in extending credit to households and firms.”
The result, BMI warns, “is a contraction in credit availability that amplifies the initial tightening in financial conditions. A credit crunch would constitute a meaningful downside risk for developed market economies.”
Credit, BMI adds, is central to supporting activity, as it finances household spending and business investment – which together account for the bulk of developed markets’ output, averaging 74% of GDP. “A broad-based tightening in credit conditions,” BMI concluded, “could therefore act as a significant drag on economic growth.”
All this puts France’s fragile finances are back in focus. Prime Minister Sébastien Lecornu is racing to finalize €54 billion ($61.8 billion) in spending cuts by early October, arguing fiscal discipline alone can close one of the eurozone’s largest deficits.
Fitch had warned back in September 2025 that French debt would climb toward 121% of GDP by 2027 without a credible stabilization path. It’s being proven right: French debt is now projected to hit a record 119.3% of GDP in 2026, per the finance ministry.
Eurasia Group’s Mujtaba Rahman notes the bind: a tough 2027 budget risks toppling Lecornu’s government ahead of next spring’s presidential election, even though most parties want to avoid that outcome.
Measures like a pension freeze will draw fierce pushback, but Lecornu appears set on pushing the budget through anyway — the first real step, in theory, toward fixing France’s finances. It previews the eurozone’s broader problem: yields jumping to multi-year highs.
Yet Japan may be the most powerful accelerator of global turmoil as the “yen-carry trade” grows decidedly wobbly. The yen’s recent plunge to 40-year lows even drew a rare response from the US Treasury Department.
US Treasury chief Scott Bessent engaged in Washington’s first all-in joint yen intervention since 1998. The resulting jump in the yen isn’t what Bessent had hoped for, but it’s been enough of a turn to upend currency markets.
The foreign exchange theatrics coincide with the 41st anniversary of the 1985 “Plaza Accord,” which sharply boosted the yen against the US dollar. By some measures, the dollar-yen misalignment is about 33%, with “fair value” of between 105-125 yen to the dollar from about 158 now.
Though Bessent’s real concern is China’s rising competitiveness, his focus on the yen speaks to Trump World’s worry that the dollar is too strong as US manufacturing wanes.
Trump’s desire for a “Mar-a-Lago Accord” would mostly target the Chinese yuan – and a record $1.2 trillion trade surplus despite rising US tariffs. But since the 1980s, when Trump was a New York real estate mogul, Japan has been a key economic boogeyman in his worldview of countries he believes take advantage of the US.
Trump and Bessent also clearly view Tokyo’s policy as more malleable than Beijing’s. Bessent, for example, spent recent months railing against the Bank of Japan for not tightening faster. He even warned traders that “I am the house” when bets against the yen and the BOJ are concerned.
Bessent has had far less to say about the People’s Bank of China, which remains biased toward lower rates. This is despite China’s much greater economic scale with annual GDP of $20.8 trillion versus Japan’s $4.3 trillion.
Part of the worry is that Tokyo is the biggest holder of US Treasuries with $1.1 trillion. Team Bessant clearly worries that Japanese officials might sell large blocks of dollars to stabilize the yen, setting off a panic in markets and sending yields even higher in the US and everywhere else.
Markets and their resident bond vigilantes, of course, are way ahead of this possible dynamic.
Follow William Pesek on X at @WilliamPesek
