Search warning sounds are on the rise, Google parent company Alphabet's market value evaporated by $138 billion.

For over a year, shareholders of Google's parent company, Alphabet Inc., have been concerned that artificial intelligence could pose a long-term risk to the company's "money-making machine" search business. This week, the threat has become more urgent. On Wednesday, a high-ranking executive at Apple revealed in court that the iPhone maker is exploring adding artificial intelligence services to its web browser, for which Google currently pays around $20 billion annually to be its default search engine. What is even more worrying is that, according to Apple's Senior Vice President of Services Eddy Cue, search traffic on Apple's Safari browser saw its first decrease last month. As a result, Google's Class A stock price significantly declined.