Alphabet Shares Slide 13%, Erasing Nearly $490 Billion in Market Value

Alphabet shares fell as much as 13% during early U.S. trading Thursday, erasing nearly $490 billion from the market value of Google’s parent in a sharp move for a major U.S. technology stock.

The decline reached that level as trading began on U.S. markets. The estimated loss exceeded the $421 billion increase in Alphabet’s market value recorded during one session on May 1. The comparison puts Thursday’s decline above an earlier one-day gain in the same measure.

Market capitalization—the total market value of a company’s publicly traded shares—measures how investors value its equity at a given time. A drop in that figure is not an estimate of cash lost by the business. Alphabet is the publicly traded company behind Google, and the decline centered on its shares in the U.S. market.

The three major U.S. stock indexes also opened lower, marking a weaker start for the broader U.S. market.