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After a steady climb this year, 30-year bond yields in America, France, Japan and Britain are near their highest since the global financial crisis of 2007-09. Britain has long surpassed even the highs reached during its fiscal panic in 2022. For anyone hoping yields would return to the lows of the 2010s as post-pandemic inflation fell, markets have supplied a decisive answer: they will not — if anything they are likely to climb higher still.
- 30-year yields in America, France, Japan and Britain are near post-crisis highs, and markets signal no return to 2010s lows.
- Governments are betting economic growth — now meaning AI — will pay the bills, but higher market rates have arrived before faster growth.
- Without fiscal prudence, bonds are a punt on AI that looks as risky as betting on volatile tech stocks.

30-year yields near highs last seen in global financial crisis
Of GDP: extra US interest cost within a decade per 1pp rise in yields
Data-centre investment this year, per Goldman Sachs
Why long-term yields will not fall back to 2010s lows
The culprits are clear. Inflation has not quite been beaten, deterring central banks from cutting interest rates. Even Japan is leaving behind its loose-money policies — though not enough to strengthen the yen, which both Japan and America have propped up with official purchases.
Gaping rich-world budget deficits show little sign of narrowing meaningfully, raising the possibility that governments eventually force central banks to inflate their debts away. Geopolitical ructions, like the Iran war and tariffs, are lifting the compensation for risk that investors demand. It does not help that Kevin Warsh, the new Federal Reserve chair, fumbled an early encounter with the markets.
The fiscal squeeze is getting tighter
High bond yields are a problem for indebted governments. Every percentage-point rise in America’s bond yields, for instance, costs it extra interest payments worth 1.3% of annual GDP within a decade.
Yet it is getting harder to imagine governments making cuts to offset the squeeze. In America each political party seems to be hoping that any debt crisis lands on the other. France’s presidential election next year could become a fight between populist parties on the left and right. Japan is, bizarrely, undertaking a fiscal stimulus. The longer governments wait to adjust, the bigger the adjustments become.
The AI growth bet — and why rates have risen first
Governments look increasingly as if they are betting on economic growth to pay the bills — which today means a bet on AI. The trouble is that faster growth, by boosting investment, usually brings higher interest rates and higher bond yields. Today higher market rates have arrived before faster growth.
The sheer scale of data-centre investment, pegged at $1trn this year by Goldman Sachs, a bank, is making capital scarcer and helping raise yields. However, AI has yet to boost productivity measurably, even in China where diffusion of the technology is arguably the furthest along.
Productivity gains take time and will not be evenly shared
It could be a while before the boost comes. Electricity and computing took decades to raise productivity growth perceptibly. Not all economies will fare equally well, either.
Europe’s fiscal woes could worsen if AI brings more growth for America, pulling up global interest rates, but gets jammed up in the old world by rigid labour markets and high energy costs. That would mean costlier debt without any more growth.
Even a boom would bring new fiscal costs
There is another problem, too. If the productivity boost from AI is large enough to transform any country’s fiscal arithmetic, vast job disruption is probably coming, meaning more spending on unemployed workers. Income may also shift from labour to capital, which is more lightly taxed.
Should AI prompt an arms race, countries will also need more defence spending. Even the exciting prospect of longer lifespans, fuelled by AI-powered scientific advances, would raise state spending on pensions. Economists at the Brookings Institution, a think-tank, reckon these factors plus higher interest rates could more than halve the positive impact of AI-induced growth on American deficits.
Growth alone has never been enough
The last time much of the rich world, including America and Britain, ran budget surpluses was at the turn of the millennium. That required fast productivity growth, which came from computers and the early internet. But deficits had to be cut, too. Without fiscal prudence, bonds are a punt on AI that looks just as risky as betting on wobbly tech stocks. ■
Sources
Bond yields and fiscal analysis: market data for 30-year sovereign bonds; Goldman Sachs estimate of $1trn data-centre investment; Brookings Institution analysis of AI effects on US deficits.
Image: Getty Images.
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