Wells Fargo & Co. joins JPMorgan in adopting a cautious stance on US stocks as September begins. Led by chief equity strategist Ohsung Kwon, the firm's analysts warn of "broad cautiousness" heading into what is historically the worst month for equities. Investors are increasingly anxious about the sustainability of the AI investment boom, with capital expenditure fears expected to peak.

Despite a mid-August selloff, the bank's sentiment indicator remains more positive than negative. The caution comes amid uncertainty surrounding the artificial-intelligence trade and upcoming midterm elections, marking the second bank this week to shift to a bearish outlook on the US equity market.