U.S. stocks opened the week lower, with the S&P 500 down 0.52% to 7,623.68 and the Nasdaq Composite off 0.21% to 25,955.34, as a packed week of earnings from the largest technology companies collided with fresh political uncertainty in Brazil and Serbia.
Monday's session carried the theme that has dominated 2026's rally and its occasional wobbles alike: a handful of AI-linked companies accounting for an outsized share of the market's direction. The Wall Street Journal's live markets coverage described the mood as "AI jitters," with investors parsing whether this earnings season's results can keep justifying the sector's valuations.
A busy week ahead
Traders are bracing for a run of major technology earnings reports this week, against a backdrop of a Federal Reserve that has stayed cautious on further rate cuts. Treasury yields were little changed in early trading, and the dollar firmed slightly against the euro, with EUR/USD at 1.1215.
Overseas developments added to the uncertainty. Brazil's stock market was expected to see volatility after Luiz Inácio Lula da Silva's come-from-behind election win over Flávio Bolsonaro, a result some investors worry could slow the pace of market-friendly reforms pursued ahead of the vote. Separately, the fall of Serbia's long-ruling party added to a sense that Monday's trading floor had more than earnings to digest.
What to watch
Analysts said the market's reaction to this week's technology earnings would be the more durable signal for where stocks head into year-end, with the concentration of gains in a small number of AI-linked names leaving the broader index vulnerable to any disappointment from that group.