September's sluggish start in US stocks may shape the next monetary policy decision

September’s Stock Market Start: A Classic Bad Month?

When the trading bell rang on the very first day of September, investors watched as the S&P 500 slipped 1.91 % and the Nasdaq 100 barreled down 2.9 %. A steep dip that’s as old as the season itself.

Why September is Rough Business

Historical Pattern: From the 1970s onward, September has been the perennial underdog on the calendar—negative returns for the S&P 500 in almost every year.
Recent Trends: The past five years haven’t been kinder. In 2022 the index was down –9.3 %, and in 2021 it dropped –4.7 %. A gloomy streak that warns, but we’ll see if it keeps booming.
Not a Guarantee: The “September effect” isn’t a prophecy—just a pattern that investors keep an eye on.

Economic Pulse in the Spotlight

With July’s non‑farm payroll data fresh in minds, the market’s focus has pivoted from inflation to the overall health of the U.S. economy. The big question: Will the Fed trim rates by 25 or 50 basis points by mid‑month?

Data‑Driven Week Ahead

Manufacturing PMI: Continuing contraction for the fifth straight week.
JOLTS Vacancy & Non‑Manufacturing PMI: Analysts expect a slide from July and August levels—watch these ladders.
Non‑Farm Payroll (NFP): The central star. If unemployment stays above 4.3 % or accelerates, the Fed might lean toward more easing.

Bottom Line for Investors

September has opened on a bearish note, in line with its long‑standing seasonal memory. Coupled with a week packed with data that could tip monetary policy, investors will do well to keep a close watch on the next few releases.