Alphabet’s stock experienced a historic decline Thursday, pulling the U.S. stock market lower despite widespread gains among other companies. The S&P 500 slipped 0.3 percent, ending a four-day streak of gains, while the Nasdaq composite fell 1.4 percent and the Dow Jones Industrial Average dropped 132 points, or 0.3 percent. Alphabet, the parent company of Google and YouTube, recorded its worst single-day drop since its Class A shares began trading over two decades ago, falling 12.6 percent.

The decline followed Alphabet’s release of quarterly results that showed weaker growth over the summer than analysts had anticipated. The report heightened concerns about whether the company’s significant investments in artificial intelligence (AI) technology will yield the anticipated returns. Alphabet disclosed that it burned through more cash in the latest quarter, with capital expenditures surpassing $51 billion, reflecting heavy spending on property, equipment, and AI infrastructure.

These developments have fueled broader unease within the AI industry, where a rapid expansion of data centers and AI chip inventories has raised doubts about profitability and productivity improvements. Additionally, the rising costs of borrowing have intensified pressure on future spending for data center construction and chip purchases.

Without Alphabet’s decline, the S&P 500 would have posted gains, as four out of every five stocks in the index rose Thursday. Several companies reported better-than-expected summer earnings, contributing to gains in their stock prices. KLA Corp., a semiconductor equipment supplier, increased 5.5 percent. Pharmaceutical companies also saw notable gains, with Eli Lilly climbing 6.6 percent and Merck rising 3.8 percent. Mastercard added 4.2 percent following positive earnings reports.

DoorDash’s stock rose 5.6 percent after announcing an agreement to acquire Instacart in a deal valued at $17 billion and reporting stronger quarterly profit and revenue than projected. Norwegian Cruise Line Holdings jumped 13.4 percent after surpassing earnings and revenue expectations, buoyed by increased onboard spending by passengers.

In the bond market, Treasury yields declined amid mixed economic reports. A preliminary assessment suggested that U.S. economic growth may have accelerated more than expected during the summer, supported by consumer spending and business investments in AI. However, income growth slowed in September, and inflation measures worsened. Initial unemployment benefit claims dropped, potentially indicating fewer layoffs nationwide. The yield on the 10-year Treasury note decreased to 4.98 percent from 5.05 percent, continuing its retreat from recent highs above 5.3 percent.

Oil prices also fell, with Brent crude dropping 0.8 percent to $110.80 per barrel. International equity markets saw mixed results; European indexes rose following the European Central Bank’s decision to hold interest rates steady, while South Korea’s Kospi declined 1.2 percent due in part to a 4.1 percent drop in Samsung Electronics shares, despite the company’s stronger profit report.