The decline follows the online search giant's first-quarter results, which included sales that missed analysts' average forecast by about $1 billion.
Alphabet reported first-quarter revenue and adjusted earnings per share of $36.34 billion and $11.90, respectively. On average, analysts were expecting revenue and adjusted earnings per share of $37.33 billion and $10.61.
While Alphabet's adjusted earnings per share for the period was notable, the rare revenue miss took the Street by surprise, especially since the miss was so substantial.
"In terms of our key revenue drivers, with respect to Sites revenues as we indicated last quarter, the timing of product changes in ads at times can have an impact on year-on-year growth rates," said Alphabet CFO Ruth Porat during the first-quarter earnings call, suggesting the timing of changes to its ad products may have had an adverse impact on the quarter's revenue growth rate.
Management also noted during the call that when it comes to revenue growth, it will always prioritize the long-term interest of users and advertisers. Its efforts to make product changes by improving the advertiser and user experience, therefore, could lead to more lumpiness in revenue growth in the future. But if revenue growth decelerates meaningfully and consistently in the coming quarters, investors may need to revisit their growth expectations for the company.