Alphabet reported strong growth in the September quarter, but the results also highlighted the cost of keeping pace with the artificial intelligence (AI) race. The company is investing heavily in computing infrastructure to develop and run AI models and services. At the same time, AI is changing how people use Google Search, raising questions about how the company will continue to earn money from its biggest advertising business.

The concerns are not about whether the Alphabet is growing. They are about how much it will have to spend to sustain that growth, and whether its AI investments will generate enough returns.