The major averages finished lower this week as concerns surrounding the cost of the AI buildout weighed heavily on mega-cap growth stocks, overshadowing strength across semiconductor, energy, and several cyclical sectors. The Nasdaq Composite fell 2.1%, while the S&P 500 declined 0.6% and the DJIA lost 0.4%. Although earnings season produced a number of upbeat corporate results, investor attention increasingly centered on AI spending, rising oil prices, and higher Treasury yields.
The week's defining catalyst came Thursday following earnings from Alphabet and Tesla. Both companies outlined more aggressive investment plans, reinforcing expectations that hyperscalers will continue spending heavily on AI infrastructure while raising fresh questions about margins, free cash flow, and how quickly those investments will generate meaningful returns. The "Magnificent Seven" collectively shed roughly $800 billion in market capitalization during Thursday's session, driving sharp weekly declines in the communication services (-6.2%) and consumer discretionary (-6.1%) sectors.
The selling was far more concentrated among the companies funding the AI buildout than those supplying it. The information technology sector edged 0.4% higher. The contrast suggested investors remain constructive on AI infrastructure demand but are becoming more sensitive to the growing cost of that investment for the largest technology companies.
Oil prices provided another major theme throughout the week. WTI crude rose roughly 10.5% as escalating tensions involving the U.S., Iran, and Houthi forces fueled concerns about broader regional conflict and potential supply disruptions. The move pushed Treasury yields higher, increased expectations for Federal Reserve tightening, and created a more challenging backdrop for growth stocks.
Despite the weakness in mega-cap technology, leadership broadened elsewhere in the market. Energy (+3.8%) finished as the top-performing sector, while utilities (+2.5%) and industrials (+1.8%) also posted solid gains, helping limit the broader market's losses.
Overall, the week highlighted a subtle but important shift in the market's AI narrative. Demand for AI infrastructure remained robust, but investors became increasingly focused on the economics of the unprecedented capital spending required to support it. That distinction left the broader market only modestly lower while producing a much steeper decline across the Nasdaq and the largest growth stocks.
DJIA: -0.4% week-to-date
S&P 500: -0.6% week-to-date
S&P Mid Cap 400: -0.9% week-to-date
Russell 2000: -1.1% week-to-date
Nasdaq Composite: -2.1% week-to-date