Under the triple pressure of supply, politics, and data, is the historical curse reappearing? Global long-term bonds may face the "most dangerous September."
Global long-term bonds face historic risks in September, with the median decline of government bonds with maturities over ten years reaching 2% in September over the past decade. Multiple factors such as government debt expansion, geopolitical uncertainty, and cautious market sentiment are putting pressure on long-term bonds. Investors need to pay attention to the upcoming U.S. non-farm payroll data and Eurozone inflation data, as these will influence the Federal Reserve's interest rate cut expectations. Seasonal supply patterns also affect bond performance in September, as supply typically rebounds during this time
According to Zhitong Finance APP, historical data shows that long-term bonds may be facing a dangerous September market. Data indicates that over the past decade, the median decline of global government bonds with maturities over 10 years in September reached 2%, making it the worst monthly record of the year. In the current market environment, multiple factors are putting pressure on long-term bonds, and investors need to be wary of the risk of further inversion of the yield curve.
The expectation of government debt expansion is becoming the primary source of pressure. As governments in multiple countries increase fiscal spending, the expectation of increased supply of long-term bonds continues to ferment, and the yield advantage of shorter-term bonds has gradually faded.
Geopolitical disturbances have exacerbated market uncertainty: Japan's inflation remains high, France's political situation is in turmoil due to Prime Minister Borne's confidence vote, and the unique policy games of the U.S. election year—if the Trump administration pressures the Federal Reserve to cut interest rates, it may further increase domestic price pressures. All these factors are negative for long-term bonds.
Market sentiment has shown cautious signs. Hideo Nakatsukasa, a senior portfolio manager at Five Star Asset Management, pointed out that September is usually a key window for monetary policy turning points and a sensitive period for reshaping market expectations.
Currently, institutional investors are generally adopting a defensive posture, focusing on two major risk events: the U.S. non-farm payroll data to be released on Friday will validate the reasonableness of the Federal Reserve's interest rate cut expectations, while any unexpected fluctuations in Eurozone inflation data may break the consensus of the European Central Bank maintaining interest rates.
Seasonal supply patterns are also a key focus for strategists. Chris Weston, head of research at Pepperstone Group, and Mohit Kumar, chief European strategist at Jefferies International, both believe that the weak performance of long-term bonds in September is closely related to the issuance rhythm. Typically, bond issuance is low in July and August, while supply tends to ease again after mid-November, making September a cyclical node for supply recovery, which explains the seasonal decline from a supply and demand perspective.
Evelyne Gomez-Liechti, a multi-asset strategist at Mizuho International, emphasized that the bond market this month still needs to overcome multiple challenges: if U.S. economic data continues to exceed expectations, it may delay the Federal Reserve's interest rate cuts, and if the Bank of Japan releases hawkish signals, the global interest rate environment may face repricing. Against the backdrop of rising bond yields in France due to the political crisis, multiple risks intertwine to make September a truly "dangerous month for bonds."
