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Having spent the last 20 years accumulating ever-greater piles of debt, governments now face tough choices/ difficult decisions.
What if there was one weird debt management trick that would allow governments to slash debt-to-GDP without spending cuts, tax raises, financial repression, inflation or default?
There is. But it’s terrible.
As a broad metric of fiscal health, debt-to-GDP has simplicity on its side. It means we can quickly summon charts like this one, showing quite how indebted governments are today compared to yesteryear:
And simplicity can be great for catalysing public policy.
While the US debt-to-GDP numbers don’t seem to be high enough to prevent the US Congress from pushing through monster tax cuts for the super-rich, they do appear high enough to force US Congress to slash spending on the poor.
But simplicity can also be . . . simplistic? So simple that it can be easily gamed.
All governments need to do is exchange their old bonds (trading sometimes far below par) for shiny new current-coupon bonds. Doing so would, in some cases, slash debt-to-GDP.
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To get a (very) rough estimate as to the potential impact that such a hypothetical Big Beautiful Bond Exchange™ might have on debt ratios, we cross-referenced average bond prices in the Bloomberg Global Treasury Index with the IMF’s estimates for debt-to-GDP.
The big winners of any massive debt swap look to be the United States (for sheer dollar debt reduction), Japan, and the UK (in cutting debt ratios).
True, looking more closely at the US, our working assumption that all US government debt is tradeable US Treasuries in the bond index turns out to be a bit of a stretch. According to the US Treasury, these make up less than half of total debt:
So sure, swapping old USTs trading at a discount for current coupons would cut US federal debt by $1.6tn — or around 50x itemised Doge savings — it’s still only five and half per cent of GDP, which is less than a single year of Trump’s planned deficit.
It hardly seems worth the bother.
How about a closer look at the UK, where gains could be greater relative to GDP?
The British government spent years selling shedloads of low-coupon gilts when yields were on the floor. In today’s higher-yielding environment, this means oodles of bonds trading at deep discounts.
Keen readers will recall that low-coupon gilts are pretty useful to UK taxpayers and hedge funds alike. And this has led to the gilt curve looking pretty kinky.
We’ve drawn the curve below, colouring each bond according to its coupon:
We calculate that swapping all gilts into current coupon bonds in a bondholder-friendly exchange could wipe £355bn off the face value of government debt and cut the debt-to-GDP ratio by around 13 percentage points — from 101 per cent to a mere 89 per cent. And that’s before we even look at inflation-linked gilts.
But the eagle-eyed among you will have noticed that bonds with the lowest yields on the curve are all low-coupon gilts (in red). And bonds with the highest yields on the curve tend to be more recently issued gilts (in blue).
If swapped (on a non-coercive basis), our massive gilt exchange would see the richest bonds on the curve swapped into the cheapest ones — increasing the cost of debt. And so this is not an exchange that any government with an eye to actual economics of debt management — rather than mere optics — would think sensible.
So what?
Our mad exchange plan tells us something about debt-to-GDP. Bean-counters consider only principal payments to be debt; they just ignore coupons. The Big Beautiful Bond exchange reduces debt-to-GDP because the market would be nuts not to consider both.
Debt service as a percentage of GDP is — in general — a far more thoughtful way of considering debt-imposed constraints on current government finances. Whilst debt-to-GDP breaching the 100 per cent threshold may grab headlines, political appetite for fiscal consolidation reliably starts to pick up only when debt service rises. And eyeballing the chart below, when it breaches five per cent of GDP it has generally been met by a punchy response.
What does our one weird trick do to debt service? Nothing good.
Putting it altogether
The chart below shows where we are today on both debt-to-GDP and debt service across the G7. If you scroll down you can see where these ratios might head if we played OneWeirdTrickenomics without letting pesky facts as to the true composition of government debt get in the way.
Debt service ratios today are not particularly alarming across the G7. A massive bond exchange into current coupon bonds to cut the debt load would push interest bills immediately higher.
Of course, as debt matures and is refinanced at higher interest rates, debt service costs will tick up anyway.
But fiscal policymakers have time on their side. The average maturity of JGBs is almost ten years. The average maturity of gilts is over 12 years. If the UK and Japanese economies grow faster than their debts over these periods, the degree to which debt service rises will be limited.
Things look more challenging in America. The average maturity of US Treasuries is around seven-and-a-half years. And in practice US debt service is much more responsive to interest rate moves because of all the T-bills they print. In their long-term forecasts, the CBO reckons that debt service will rise to 5 per cent of GDP — although not until 2050. This is based on their expectation that the fed funds rate falls quickly to 3.25 per cent and that 10-year Treasuries stay below 4 per cent. Furthermore, the CBO long-term forecasts don’t yet incorporate the Big Beautiful Bill. So today their forecasts look optimistic.
What does it all mean?
Today’s government debt loads are high but not unprecedented. Cutting them down to size through our massive debt swap plan would clearly be preposterous (although swapping long expensive debt for shorter cheaper debt would not). Sure, it would lower the debt-to-GDP ratio in a number of countries. But only because the ratio is silly. Interest bills would be jacked up in the short run. And this is before we factor in any vibes-based premium that might be applied by the market for mucking about.
Sorry guys, difficult decisions it is.