Apple Inc. and Amazon.com Inc. have reported disappointing quarterly results, in a sign that the global supply-chain crisis is hobbling even the mightiest companies, erasing hundreds of billions of dollars from their combined market valuations.

Amazon, the world’s largest e-commerce company, is suffering because of a surge in the cost of labor and fulfillment. Apple, meanwhile, is taking a hit because it can’t meet demand for its products.

But added together, the tech giants delivered a clear message to investors: This holiday season is going to be difficult. As the economy emerges from the worst pandemic in a century, getting enough products to consumers is a daunting challenge for nearly everyone.