February 5 (Reuters) - Wall Street ended trading sharply lower on Thursday, with the Nasdaq index falling to its lowest level since November due to losses in shares of Microsoft, Amazon and other major technology companies.

These losses came after Alphabet, Google's parent company, announced it might double its capital spending on artificial intelligence in its race to dominate this emerging technology.

Alphabet shares fell 0.55 percent after it announced plans to inject up to $185 billion in capital expenditures in 2026. It and its Big Tech rivals are expected to collectively spend more than $500 billion on artificial intelligence this year.

Adding to the latest losses, shares of Microsoft fell 5 percent, Palantir 6.8 percent, and Oracle 7 percent.

Amazon's stock fell 4.4 percent during trading and then another 10 percent after the market closed, as it joined its peers among major technology companies in anticipating massive capital expenditures in 2026.

Shares of chipmaker Nvidia, which stands to benefit from increased industry spending on artificial intelligence, fell 1.4 percent.

"This is the first time we've seen the big technology companies, Microsoft, Alphabet and Amazon, go through a really big capital spending cycle," said Tom Heinlein, investment analyst in the wealth management division at U.S. Bank in Minneapolis.

Investors this week also expressed concern that the rapid improvement in artificial intelligence tools could negatively impact demand for traditional software, putting pressure on profit margins in the sector.

The S&P 500 fell 1.23 percent to close at 6,798.40, the Nasdaq Composite dropped 1.59 percent to 22,540.59, and the Dow Jones Industrial Average declined 1.20 percent to 48,908.72.