That math pummeled the stock Thursday. Alphabet’s Class A shares fell 12.6% to $283.82, their worst day since they began trading in 2004. The decline wiped out about $482 billion in market value. Previously, Alphabet’s worst day was in March 2020 when the stock dropped 11.6%.

The trigger was the search business—the same juggernaut that turned Google into a verb. Search and other revenue grew 12% in the third quarter to $63.35 billion. Analysts expected 15%. That miss on growth momentum compares to 17% growth in the second quarter and 19% in the first. Meanwhile, Google Cloud’s revenue more than doubled, up 103% to $30.71 billion. But Alphabet spent $51.4 billion on capital expenditures in the quarter, more than double a year earlier, and free cash flow came in at negative $9.1 billion, according to its earnings release.

Three months ago, BofA analyst Justin Post had the whole company at about 22x his 2027 earnings estimate, which he called in line with historical averages. On Thursday, at the after-hours price of about $291, he had it at about 19x, with core search at about 10x inside that. He kept his Buy rating, cut his price target to $380 from $430, and lowered the multiple he’s willing to pay to 24 times from 27, citing the “slowdown in high-margin search growth.”

“Search AI transition will fuel the bears,” Post and co-author Nitin Bansal wrote.

“The bears will argue this is the first quarter that AI is starting to seriously hurt their search business,” Pivotal Research CEO Jeffrey Wlodarczak said, as previously reported by Yahoo Finance.

More searches, slower growth

The search slowdown comes even as Google says more people are searching. “Our year-over-year query growth rate is the highest it’s been in the last 5 years,” CEO Sundar Pichai said on Wednesday’s earnings call.

BofA estimates search growth, excluding currency moves, slowed three percentage points from the prior quarter, “despite accelerating y/y query growth.” The analysts put most of that on a comparison that was two points tougher than last quarter’s. They wrote that Google indicated the shift of traffic to AI Overviews, the AI-written summaries at the top of results, was a small headwind in the quarter. They added that it’s “likely bigger” internationally, where advertising loads in those summaries are just starting to ramp.

Google’s answer is more ads inside the summaries. “We’re now scaling high-quality ads within AI Overviews and AI Mode to more users and queries,” chief business officer Philipp Schindler said on the call. “This includes taking our monetization footprint global for the first time.”

The summaries change what users do on the page. A Pew Research Center study published in July 2025 found that users who saw an AI summary clicked a traditional search result on about 8% of visits, compared with 15% when no summary appeared. That study measured clicks to websites, not Google’s ad revenue.

Paying for the cloud

Most of the gap between Alphabet trading at 19x earnings and search’s 10x earnings comes from the boost in value from Google Cloud. Its operating margin was 36.2% in the quarter, up from 23.7% a year earlier. There’s also another revenue stream to add in to the sum-of-the-parts. BofA now models $75 billion in 2027 sales of TPUs, Google’s in-house AI chips, to outside customers.

The cloud business is also where the capex goes, and the bill keeps growing. Chief financial officer Anat Ashkenazi said in July that Alphabet expects capex “to increase significantly in 2027.” The company confirmed its full-year capital spending forecast this week and indicated that capex is expected to reach $200 billion in 2026, and then rise to $300 billion in 2027. The quarter’s earnings also took a one-time $8.7 billion mark-to-market hit on Alphabet’s SpaceX stake, which BofA said cost 55 cents a share.

The founders took the hit on paper too. Larry Page and Sergey Brin lost an estimated $60 billion combined, according to Forbes estimates.

A 2027 story

BofA’s bull case runs on a calendar. Tougher comparisons last through the second quarter of 2027, “which could make Google a 2H’27 story,” the analysts wrote. They also see “potential for a growth uptick as early as 1Q,” helped by international ads in AI Overviews.

Their model doesn’t count Alphabet’s moonshots at all. “Early-stage bets like Waymo & quantum computing offer meaningful long-term optionality,” they wrote, “not in valuation.”

Generative AI was used for research assistance and/or transcription of this article. The reporter independently reported and verified the factual claims in this article, and a human editor reviewed it before publication.