S&P 500 & Nasdaq Post Best September in 15 Years

 

📈 S&P 500 & Nasdaq Post Best September in 15 Years

In a remarkable turn, September 2025 became the strongest month in over 15 years for both the S&P 500 and Nasdaq Composite indices. The S&P rose ~3.5%, while the Nasdaq surged ~5.6%, defying the so-called “September Effect” that tends to produce weaker results historically. MarketWatch

🔍 What’s Behind the Rally

• Monetary Easing Expectations: The market is pricing in additional Fed rate cuts, expecting the central bank to be more accommodative given softening inflation signals.

• AI & Tech Momentum: Strength in large tech names, especially those linked to artificial intelligence, fueled optimism and attracted fresh capital.

• Record Highs & Momentum: Many stocks hit 52-week highs — for example, the S&P posted 30 new highs, and Nasdaq recorded over 150 new highs on the month. Reuters+1

• Resilience Despite Macro Headwinds: Even with concerns over tariffs, a possible U.S. government shutdown, and late-cycle risk, investor enthusiasm held up.

⚠ Historical Context

This performance is notable because September is typically one of the weakest months for equity markets. On average, the S&P 500 has posted negative returns in September historically. The Motley Fool+1 That makes this month’s gains all the more exceptional.

📌 Key Stats & Signals

• The S&P’s advance capped a string of benchmark records, with many constituents reaching fresh highs. Reuters+2Yahoo Finance+2

• Valuations are elevated: the S&P’s price-to-peak earnings ratio temporarily touched 27.7, one of the highest levels since the dot-com era. Charlie Bilello's Blog

• Analysts project modest upside from here; many peg year-end S&P targets in the 6,500–7,100 range. Nasdaq