Global stocks declined as concerns over the continued surge in artificial intelligence investment overshadowed Alphabet's strong financial results. Meanwhile, Brent crude rose for a fifth straight day.

Nasdaq 100 futures fell 0.7%, and S&P 500 futures dropped 0.5%.

Alphabet shares fell more than 3% in late after-hours trading after the company raised its capital spending forecast to as much as $205 billion this year, up from its previous estimate of $190 billion and more than double its 2025 spending target.

However, expectations of increased spending by major cloud computing companies boosted chip stocks in Asia, pushing South Korea's Kospi index up 4.4%. The MSCI Asia Pacific index rose 1%.

In Europe, the Stoxx 600 index slipped 0.7% on a busy day of earnings announcements, with STMicroelectronics and Nestlé shares weighed down after disappointing results. The European Central Bank is scheduled to announce its latest interest rate decision later today.

The continued rise in oil prices also weighed on markets after the Red Sea became a new flashpoint for supply disruptions from the Middle East, pushing Brent crude above $97 a barrel.

Global bond yields continued their upward trend as traders increased their expectations for tighter monetary policy; the yield on the benchmark 10-year US Treasury note rose two basis points to 4.67%, and the yield on the UK's 10-year government bond climbed four basis points to 5.08%.

While the US dollar remained stable, spot gold fell 0.9% to $4,095 an ounce, and Bitcoin declined 0.7% to $65,418.

The justification for massive investments in artificial intelligence preoccupied markets. Alphabet's results came at a time when markets were assessing the ability of major cloud computing companies to justify further investment in AI. Despite this, chipmakers and other companies that supply components for developing AI infrastructure are reaping the benefits as demand for their products and services remains high.

Mabrouk Chitwane, director of global markets strategy at Natixis IM, told Bloomberg, "There are always doubts about whether these massive investments will deliver the desired returns, but I think that question is misplaced; technology companies don't have the luxury of not spending heavily." He added, "The momentum of capital spending has peaked, indicating that strong demand for semiconductors is continuing."

Tesla Inc. shares fell 4% after missing estimates, while International Business Machines Corp. shares dipped slightly after it lowered its full-year sales forecast.