• The final S&P Global (SPGI) U.S. Manufacturing PMI for September came in at 55.9, down from the 57.0 flash estimate but well above August's 53.9, indicating continued strong growth in factory activity.
  • Input prices surged, with the prices paid index hitting 66.4, the highest since October 2022, while supply chain delays intensified.
  • The data reinforces expectations of resilient economic growth but complicates the Federal Reserve's fight against inflation.

Manufacturing Momentum Cools Slightly

U.S. manufacturing activity expanded at a robust pace in September, though slightly less than initially estimated, according to the final S&P Global Manufacturing PMI released on Monday. The index fell to 55.9 from a preliminary reading of 57.0 but remained significantly above August's 53.9. A reading above 50 indicates expansion, and the September result still points to one of the strongest improvements in factory conditions since May 2022.

The downward revision suggests that while demand remains strong, the acceleration in production, new orders, and hiring was not quite as explosive as the flash estimate indicated. Still, the broader private-sector picture was also bright: the S&P Global composite output index, which combines manufacturing and services, rose to 58.4 in September from 56.0 in August, its highest level since July 2021. New orders across the private sector reached their highest reading since March 2022.

Inflation Pressures Build

The strong demand is exacerbating capacity constraints and driving costs higher. The PMI measure of prices paid jumped to 66.4, the highest since October 2022, while supplier delivery times lengthened to the greatest extent since July 2022. Survey respondents cited shortages of raw materials and logistics disruptions, with some linking the supply pressures to the ongoing U.S.-Israeli conflict with Iran. Record-high diesel prices are also expected to push transport costs even higher.

"The September PMI data signal a worrying combination of robust demand and worsening supply chains, which is fueling inflationary pressures," said Chris Williamson, chief business economist at S&P Global Market Intelligence, in a statement. "This will add to the Fed's dilemma, as stronger growth could keep inflation elevated for longer."

The Federal Reserve has already raised its policy rate by 25 basis points to a range of 3.75%–4.00% and signaled further increases may be needed. The PMI report is unlikely to deter policymakers from tightening further, as it underscores the resilience of the economy and the persistence of price pressures.

Growth Narrative Intact

Despite the downward revision, the manufacturing data reinforce evidence of solid economic growth. S&P Global's flash composite reading was consistent with annualized GDP growth of roughly 5%, while the Atlanta Fed's GDPNow tracker was around 5.1% at the time of the release. The strong order growth and backlog accumulation suggest that factory activity will remain firm in the coming months.

Manufacturers are benefiting from strong demand, but they are also facing rising costs. Input prices, freight, energy, and labor costs are all climbing, which could compress margins unless firms can pass these costs on to customers. For workers, the strengthening labor market—particularly in production, maintenance, and logistics roles—may improve job opportunities and bargaining power.

Investors are weighing the implications. Cyclical sectors such as industrials, machinery, transportation, and materials may benefit from the strong orders data, but the inflation and interest rate risk could weigh on long-duration assets. The stronger-than-expected activity typically supports Treasury yields and the dollar, as it reduces expectations of near-term monetary easing.

Supply Chain Woes Persist

The international dimension of supply constraints is becoming more pronounced. The conflict with Iran is cited as a factor behind shortages and logistics disruptions, while high diesel prices are making transportation more expensive. These bottlenecks could limit the ability of manufacturers to convert backlogs into actual output, potentially keeping inflation sticky.

For U.S. trade and industrial policy, the strong factory activity bolsters the case for domestic manufacturing incentives and supply-chain localization. However, it also highlights the limitations of demand-side policy when capacity, transport networks, energy costs, and skilled labor are constrained. Stronger demand may translate into higher prices rather than proportionately higher real output.

What to Watch

Looking ahead, market participants will focus on the ISM Manufacturing PMI for confirmation of the S&P Global survey's message. Other key indicators include factory orders, durable goods orders, industrial production, and inventories, which will show whether survey optimism translates into actual output. Employment and wage data, particularly for production and logistics occupations, will be scrutinized for signs of labor market tightness. Goods inflation, producer prices, diesel and freight costs, and supplier delivery metrics will also be closely monitored.

Federal Reserve communications will be critical, as strong activity plus rising input prices increases the sensitivity of markets to any change in the policy outlook. The final 55.9 reading is a modest downward revision, not a reversal: U.S. manufacturing entered September with powerful demand and improving output momentum, but also with increasingly visible capacity, supply-chain, energy, and inflation pressures.

Update: This article was updated to include the final PMI reading and additional context on supply chain pressures.