Global week ahead: Welcome to September, Wall Street’s least-loved month

Despite August seeing the S&P 500 hit a record 6,500 and European equities log a two-month winning streak, September's historical reputation as the worst month for stocks looms. Sector performance is bifurcated, with European banks reaching post-2008 highs, notably Commerzbank up over 100% YTD, while media stocks like WPP, which reported a 71% profit fall, are down over 8% amid AI concerns. Analyst outlooks are mixed, ranging from UBS's expectation of a sustained bull market on a soft landing and lower rates, to EY-Parthenon's skepticism on US growth and Barclays' forecast for a H2 slowdown. This divergence and uncertainty underscore the importance of upcoming economic data and central bank policy decisions this month.

Analysis

Markets are entering September from a position of strength, with the S&P 500 closing August at a record high above 6,500 and the Stoxx Europe 600 securing its first two-month winning streak since February. However, this positive momentum is met with significant headwinds, including September's historical reputation as the worst-performing month for major U.S. indices. A clear bifurcation is evident in European sector performance; the banking sector has reached its highest level since the 2008 financial crisis, exemplified by Commerzbank's shares surging over 100% year-to-date, while the media sector has declined over 8% in the past two months. This weakness is underscored by WPP, which reported a 71% pre-tax profit fall and cut its full-year outlook, citing concerns over AI's impact. Analyst outlooks are divergent, reflecting broad uncertainty. UBS Global Wealth Management maintains a bullish stance, forecasting a soft landing and supportive interest rates, whereas EY-Parthenon expresses caution, labeling the robust 3.0% U.S. Q2 growth a 'mirage' distorted by tariff-related import swings. This uncertainty places heightened importance on upcoming catalysts, including key policy decisions from the Federal Reserve, ECB, and Bank of England, alongside critical economic data such as U.S. non-farm payrolls and EU inflation.

Key Decisions for Investors

• Given the historical seasonal weakness in September and conflicting economic outlooks, investors should consider reviewing portfolio risk and preparing for heightened volatility, particularly around key central bank meetings.
• The stark divergence between European banking strength and media sector weakness suggests a need for a targeted, stock-picker's approach rather than broad index exposure; scrutinize holdings in sectors like media facing fundamental headwinds, as seen with WPP.
• Monitor upcoming macro data points, especially the U.S. non-farm payrolls and EU inflation and GDP figures, as they will be critical in shaping central bank policy and resolving the current debate between bullish and bearish market scenarios.