Bonds dominated the week as debt, deficit and inflation concerns pushed long-term government yields to multi-year highs.
Read this article to understand:
- Why it's been a tumultuous week for bonds
- How geopolitics continue to exert pressure
- The bright spots of the week
If there was one story that defined markets this week, it was not artificial intelligence (AI), corporate earnings or central banks – it was government bonds.
While equity markets remain close to record highs, investors spent much of the week grappling with a sharp rise in long-dated government bond yields. In the United States, the 30-year Treasury yield briefly touched 5.3 per cent, its highest level since 2007, while Germany and France saw borrowing costs rise to levels not seen for more than a decade.
America's national
debt surpassed
US$40 trillion
this week
The pressure on US bonds reflects a simple reality, America's national debt surpassed US$40 trillion this week and borrowing requirements remain high and continue to grow. At the same time, the AI investment boom is absorbing huge amounts of capital. With competition for capital rising across the economy from both governments and corporates, investors are asking for higher yields before locking it away for decades.
Energy markets added to inflation concerns as tensions between the United States and Iran kept focus on the Strait of Hormuz. Brent crude rose from below US$89 a barrel at the start of the week to above US$93 by Friday morning (August, 21), while European natural gas prices reached their highest level since early 2023. The move higher in energy prices reignited fears that inflation could remain stubbornly high and helped drive bond yields higher globally.
The higher yield environment proved challenging for equities. The S&P 500 fell in four of the five trading sessions and suffered its largest daily decline of August on Thursday, dropping 0.87 per cent. European markets also struggled, with the STOXX Europe 600 extending a run of losses. Technology shares came under particular pressure, with semiconductor stocks leading declines as the Philadelphia Semiconductor Index endured its weakest session of the month.
On Wednesday, the US Treasury announced an expansion of its buyback programme for longer dated government bonds. Investors viewed the move as an attempt to support a market that had come under increasing strain as yields surged. Initially it worked. 30-year Treasury yields recorded their largest one-day decline since June, falling more than nine basis points. The US dollar weakened sharply and gold rose more than four per cent, its strongest daily gain since March 2026.
However, the relief was short-lived. By Thursday, yields were rising once again as investors concluded that buybacks might ease short-term market stress but do little to address the bigger issues of government borrowing, persistent inflation concerns and higher energy prices. Markets appeared willing to welcome the support, but not convinced it solved the underlying problem.
There were also some notable company-specific stories. The standout performer was Moderna, whose shares surged almost 177 per cent after announcing successful trial results for a skin cancer vaccine being developed in partnership with Merck. The news sparked a rally across the healthcare sector and provided one of the week's few bright spots for equity investors.
Economic data painted a mixed picture. Earlier in the week, softer housing and industrial activity figures suggested the US economy might finally be losing some momentum. However, stronger business surveys and resilient labour market data later in the week pushed back against that narrative. The Philadelphia Fed manufacturing survey rose to its highest level since 2021, while unemployment claims remained subdued, reinforcing the view that economic activity remains surprisingly robust.
Growing divergence between stocks and bonds could become one of the defining market themes as we move into the autumn
The week leaves investors facing a difficult balancing act. Growth remains healthy, but rising oil prices, elevated government borrowing and stubborn inflation concerns are pushing long-term interest rates higher. For much of 2026, equity markets have largely looked through those pressures. Bond investors are becoming less willing to do so. That growing divergence between stocks and bonds could become one of the defining market themes as we move into the autumn.1
Past performance is not a reliable indicator of future results.
References
- Source of all the data for this article: Aviva Investors and Bloomberg. Data as of August 21, 2026.
