With US federal debt surpassing the $40 trillion mark, fresh concerns have emerged regarding the nation's economic trajectory.

In a recent assessment, Morgan Stanley's global head of fixed income research, Andrew Sheets, delivered a definitive verdict: the elevated government debt load will place certain constraints on economic activity, yet it remains insufficient to trigger a systemic collapse. The continued strengthening of corporate and household balance sheets serves as a crucial buffer against potential shocks.

Sheets highlighted that US federal debt has grown by $20 trillion over the past decade, with more than $1 trillion added in just the last three months. Government debt-to-GDP ratios have risen across most major economies. Despite this, he contends that the deterioration in public sector finances is offset by simultaneous improvements in corporate and household balance sheets. This structural dynamic suggests the transmission of debt pressures to the real economy will prove far milder than market expectations.

The central question occupying investors is: amid persistently rising yields, where will the true "breaking point" for debt stress emerge? Morgan Stanley's conclusion is that this threshold is more likely to surface at the asset allocation level—specifically when bond yields become compelling enough to genuinely compete with equities for investor capital. At present, that shift has yet to materialize.

Corporate Debt: Record Issuance, Yet No Deterioration in Leverage

The Morgan Stanley report shows that corporate bond issuance is hitting record highs, driven by a surge in technology spending and a revival in M&A activity. The firm's credit strategy team projects full-year issuance will again set a new benchmark.

However, Sheets argues this wave of issuance does not constitute a systemic risk. The core rationale: US corporate debt as a share of GDP has remained roughly flat over the past decade and has declined compared to pre-pandemic levels. Hyperscaler technology firms carry low leverage, and the high returns on artificial intelligence investments provide reasonable justification for "pricing at a premium" in funding markets. The report anticipates that rising yields will not interrupt this financing wave, with credit spreads only widening modestly.

Household Sector: Locked-In Low Mortgage Rates and Improving Net Worth

The picture for households is similarly better than surface data suggests. The report notes that US household debt-to-GDP stands at approximately 67%, below the roughly 70% level seen in 2000 and down about 6 percentage points from the 74% recorded in 2019.

More importantly, this figure may actually overstate the real burden. Sheets emphasized that a substantial portion of household debt consists of mortgages locked in during the historically low-rate era, while the value of household assets has risen significantly. This helps explain why consumer spending has remained resilient despite the dual pressures of high interest rates and elevated energy costs. He also pointed out that interest-rate-sensitive sectors such as housing are already in a downturn, cautioning that the speed of household reaction to rate changes should not be overestimated.

These trends are not unique to the United States. In Europe, government debt-to-GDP ratios have risen while corporate and household deleveraging has been even more pronounced. In Japan, public borrowing has increased, but private sector leverage has stayed stable. Sheets attributes this pattern to policy choices—the US, France, Japan, Sweden, Switzerland, Italy, and the UK have all lowered tax rates over the past decade. The relative deterioration of public sector balance sheets versus private ones is the result of deliberate policy orientation.

The Real Risk: A Moment of Asset Allocation Rebalancing

The genuine threat from debt pressure to markets does not lie in corporations halting borrowing or households cutting consumption, but rather in whether investors begin to view bonds as offering more attractive risk-adjusted returns than equities.

The report points out that the current 30-year US Treasury yield sits roughly 300 basis points above expected inflation, with long-duration US investment-grade bonds yielding 6.2%. However, current fund flows and the stock-bond correlation show no clear signs of reallocation—equity and bond prices have recently moved in tandem, which is inconsistent with capital shifting from stocks into bonds.

Earnings growth is the key variable sustaining the status quo. The S&P 500 is up approximately 13% year-to-date, while the 10-year US Treasury yield has risen about 50 basis points. Yet the equity risk premium as measured by Morgan Stanley strategists—the difference between earnings yield and bond yield—has remained largely unchanged. Sheets draws a parallel between the current environment and the late-1990s market backdrop, warning that any deceleration in earnings growth would significantly heighten market vulnerability.

Relative Opportunities: UK Inflation-Linked Bonds and the Australian Dollar in Focus

Against the backdrop of divergent global fiscal landscapes, Morgan Stanley has also identified select allocation opportunities that hold relative advantages.

The report notes that the UK is among the few major economies where fiscal deficits are expected to narrow. Morgan Stanley therefore favors UK inflation-linked bonds. Additionally, with Australia's government debt-to-GDP ratio at just 49%, coupled with relatively higher carry yields, the Australian dollar also receives the firm's endorsement.

Meanwhile, Sheets maintains a cautiously cautious stance on the US dollar. He believes that if the US Treasury more actively intervenes at the long end of the yield curve, it would exert downward pressure on the dollar. He also anticipates a re-steepening trend in the 7-to-30-year segment of the US Treasury yield curve.