US Debt Tops $40tn as Long-Yield Costs Climb

US national debt has more than doubled over the past decade, passing $40tn (£29.4tn), according to Treasury data that show the level of borrowing accelerating faster than expected.

The Treasury figures put the total at $40.05tn as of 18 August, covering all outstanding Treasury bonds, bills and notes. In 2016, the US debt was just under $20tn, according to the same data series.

Debt Growth And Debt-Ceiling Pressure

The expansion has been driven by years of high government spending under both the Trump and Biden administrations, alongside rising interest payments that have added to the overall total.

The Congressional Budget Office (CBO) had projected that total borrowing would reach $39.6tn only by the end of fiscal year 2026. The faster-than-expected rise has intensified concerns about how quickly the government’s borrowing needs are increasing and what that could mean for future interest costs.

The CBO has also said the US is nearing its $41.1tn debt ceiling, with debt expected to rise to about $64tn by 2036.

Treasury Actions As Yields Reach Two Decades High

A rise in government spending to finance budget deficits has fed through to broader borrowing costs, with higher interest rates and inflation affecting consumers.

Bond yields, which determine what borrowers—including the government, companies and households—pay, have climbed sharply. On Tuesday, the interest rate on 30-year bonds reached 5.34%, the highest in almost 20 years. Freddie Mac data cited in the report show the average rate on 30-year fixed mortgages is 6.67%.

The recent increase in yields has been linked to rising oil prices related to the US-Iran war, with investors concerned about inflation.

In response, the Treasury said it planned to increase its intervention in the long-term bond market. The department described the move as reflecting “desire to provide greater liquidity support” for longer-term securities.

It said it would raise buyback operations by at least double from $2bn to $4bn, effective from 9 September to 4 November. Following the announcement, the 30-year borrowing rate eased to 5.18%.

John Canavan, lead analyst at Oxford Economics, said the buyback increase appears aimed at providing relief on longer-term borrowing costs, which he said were under “significant pressure” from higher oil prices, inflation risks, and heavy supply linked to global sovereign and corporate borrowing.

Rene Albrecht, a senior analyst at DZ Bank, said the Treasury was trying to reduce the risk of “pain of 5% or higher yields” over the long term, warning that the impact would also extend to the private sector. He said the move reflected the need for tools as the midterm elections approach.

There were also concerns about the scale of cash being raised by tech firms to develop artificial intelligence (AI), with uncertainty over timelines and returns.

Debt Load And Fed Concerns On Inflation

The report also highlighted the overall burden of US debt relative to the size of the economy. The International Monetary Fund (IMF) estimates the debt-to-GDP ratio at 125.8%, one of the highest among major economies. The IMF puts the UK and China at 103.6% and 106.9% respectively. It said Japan has the highest debt burden among major economies, with a debt-to-GDP ratio of more than 200%.

Minutes released on Wednesday by the Federal Reserve, which sets US interest rates, showed policymakers’ inflation concerns had deepened at their last meeting. The Fed kept its benchmark rate in the 3.50% to 3.75% range for a fifth consecutive meeting, after “several participants” favoured higher rates.

The minutes also noted that rate hikes would “likely be necessary if inflation did not decline”, with some participants saying the policy rate was not high enough to bring inflation back to the Fed’s 2% target. The Fed is expected to keep rates unchanged again at its September meeting after recent data showed inflation easing slightly and firms shed jobs unexpectedly in July.

Join the discussion?

20 August 2026