American factories are currently experiencing an unprecedented level of activity, a trend not observed in years. The S&P Global US Manufacturing PMI reached a preliminary reading of 55.3 for May 2026, indicating the most robust growth in the sector since May 2022. Any reading above 50 signifies growth, while numbers exceeding 55 indicate substantial economic expansion that catches the attention of economists.
Despite these promising figures, factory managers are expressing concerns. Even though the ISM Manufacturing PMI has been above the pivotal 50 threshold for four months in a row, stabilizing at 52.7 in both March and April 2026, those in the trenches feel uneasy about rising costs and economic headwinds. This marks the longest continuous growth period since the post-pandemic industrial resurgence in 2022.
In addition, the S&P Global PMI figure rose from April's final output of 55.1 to a preliminary 55.3 in May, contributing to this narrative of growth. However, rising input costs, reaching their highest levels in nearly four years, combined with output price increases, have negatively impacted the overall sentiment among manufacturers. Longer supplier delivery times, the worst since August 2022, create additional friction in the supply chain.
The ISM survey revealed that 42% of participants cited the ongoing Iran conflict as a substantial concern affecting their operational capacities. Tariffs also emerged as a focal issue, affecting 18% of respondents, highlighting the complexities manufacturers currently face.
Interestingly, the trade barriers introduced in 2025 have incentivized domestic production, prompting many supply chain managers to prioritize American-made products. This shift toward buying domestic not only supports U.S. factories but also presents a paradox, as the same tariffs increase the costs of imported raw materials that many American manufacturers still rely on.
So, what does this imply for investors? The ongoing expansion in manufacturing activity serves as a significant advantage for businesses engaged in U.S. industrial production. Four consecutive months of ISM index readings above the critical 50 mark signal a tangible trend rather than mere fluctuations. Supply chain interruptions, evidenced by worsening delivery times, tend to result in significant pricing changes in essential sectors like industrial metals, chemicals, and energy inputs.
As 42% of manufacturers express concern over the situation in Iran, instability in the region could influence industrial sentiment, potentially causing a swift shift in market dynamics.