Market Commentary: September 2026

September opened with markets confronting a less comfortable mix of resilient growth, sticky inflation, and renewed energy pressure. Escalating conflict involving Iran disrupted oil flows through the Strait of Hormuz and Red Sea routes, pushing crude prices higher and reviving concerns that the energy shock could keep inflation elevated. Treasury yields climbed alongside oil, with the 10-year yield briefly reaching 5.04%, its highest level since 2007. Higher borrowing costs and a stronger case for Federal Reserve tightening weighed on risk appetite, leaving stocks under pressure even as the broader economy continued to show resilience.

Energy became the clearest relative winner as rising crude prices supported the sector, while rate-sensitive and growth-oriented areas faced more pressure. Technology was particularly volatile. Semiconductor shares sold off sharply after leading artificial intelligence executives called for a slower pace of AI development to better address safety risks, raising questions about the durability of the infrastructure spending boom that has supported chip demand. As of September 15, the S&P 500 was up 11.7% for the year, but the late-period weakness showed how quickly higher yields and shifting expectations around AI spending could challenge elevated valuations.

Economic data strengthened the case for the Fed to act. Employers added 162,000 jobs in August, well above expectations, while the unemployment rate held at 4.1%, signaling that labor demand remained firm enough to absorb tighter policy1. The Producer Price Index (PPI) rose 0.4% in August and 5.4% over the prior 12 months, with energy costs accounting for much of the increase2. The Consumer Price Index (CPI) also rose 0.4% for the month and 3.4% from a year earlier. Core CPI, which excludes food and energy, increased 0.3%, slightly above expectations, even as its annual rate eased to 2.4%3. Together, the reports reinforced the view that inflation remains too firm for the Fed to stay comfortably on hold.

Bottom line: The focus now turns to the Federal Reserve's September 16 decision, where markets are pricing a high probability of a quarter-point rate increase to a 3.75%-4.00% target range. The decision itself may matter less than the updated rate projections and Chair Kevin Warsh's guidance on whether this is a one-time adjustment or the start of a broader tightening cycle. August retail sales arrive the same morning, followed by housing starts on September 17, giving investors an immediate read on whether consumers and housing can withstand higher borrowing costs. For markets, the key question is whether the Fed can contain inflation expectations without turning September's rise in yields into a more persistent drag on growth.

 Sources:

1.        Bureau of Labor Statistics, https://www.bls.gov/news.release/empsit.nr0.htm

2.        Bureau of Labor Statistics, https://www.bls.gov/news.release/ppi.nr0.htm

3.        Bureau of Labor Statistics, https://www.bls.gov/news.release/cpi.nr0.htm