AI Splits the Ad Duopoly: Meta's Ads Grow at Twice Google Search's Pace

Meta's advertising business grew more than twice as fast as Google's search business in the third quarter, delivering the clearest financial evidence yet that generative AI is pulling the two pillars of the internet ad market in opposite directions. Meta's ad revenue rose 26% year over year to $63.1 billion. Google's Search and other unit grew 12% to $63.4 billion. The 14-point growth gap is the widest in Meta's favor since 2021, and it puts the two ad businesses neck and neck by size — though Google collected an additional $11 billion in third-quarter revenue from YouTube.

The numbers back Mark Zuckerberg's claim that his company's artificial intelligence investments are producing better targeting tools for brands promoting goods and services across Facebook and Instagram. They also quantify Google's problem: chatbots are becoming an alternative to search, and consumers are clicking far fewer blue links, which cuts directly into search ad revenue.

What happened to Alphabet's stock?

The market delivered its verdict on Wednesday. Following its disappointing third-quarter earnings report, Alphabet suffered its worst day ever on the stock market. The shares plunged more than 12% and wiped out roughly $500 billion in market capitalization.

Meta has not escaped the pressure either. The stock fell 14% in October, its worst month since October 2022, after a 27% surge in September that marked its best month since November of that year. Investors are reacting to AI buildouts that have pushed both companies into negative free cash flow territory, with open questions about whether historic spending on AI infrastructure will generate sufficient revenue.

The stakes are enormous. Google and Facebook have dominated the internet for two decades, converting billions of eyeballs into trillions of advertising dollars. The boon in online advertising, and the hefty margins that came with it, catapulted both companies into leadership positions and lifted their market caps into the trillions.

Why is AI a 'double-edged sword' for Google?

Analysts frame the risk in blunt terms. Nate Elliott, an analyst covering AI at Emarketer, told CNBC in an email: "It's a double-edged sword, because as AI revolutionizes discovery, people might come across tools they like better than Google. If ChatGPT or Claude or Muse is better at helping them find what they're looking for, people's search habits might change for the first time in a generation. That's potentially catastrophic for Google's ad business."

The competitive set is expanding. Anthropic's Claude chatbot and Meta's recently launched Muse assistant are adding to the mix of options vying for queries that once went to Google. Meanwhile, users are spending more time scrolling Instagram, which hands Meta more advertising inventory.

UBS analysts, writing after Google's results, said the dynamic threatens the core of the business: "That's going to bring Search cannibalization fears right back to the forefront, made worse by META's ad strength this quarter and the lingering Muse/agent threat."

Wedbush analysts went further on the question of the stock itself. "GOOGL shares are unlikely to work until the search narrative changes," they wrote in a report Thursday. "And it will likely require new ad products and proof points that it can monetize in the evolving AI era as it did in the past."

How did Meta rebuild its ad engine with AI?

Meta needed AI to breathe life into its ad business after Apple's iOS privacy change in 2021 severely limited the company's ability to target users on iPhones. The following year, revenue at Meta fell for the first and only time in the company's history.

Late 2022 brought the launch of OpenAI's ChatGPT and opened the generative AI era. Meta struggled initially to find a consistent AI strategy, falling far behind OpenAI and Anthropic in developing frontier models. But the company has successfully infused AI into its ad products, giving brands advanced tools for efficiently reaching users.

A year ago, Meta unveiled the Meta AI business assistant, which advertisers can plug into the Ads Manager system to build campaigns and improve performance. CFO Susan Li said on the earnings call last week that advertisers adopting the system's recommendations "drove almost 5% more conversions" and "increased their advertising investment by 9% compared with similar non-adopters."

Li offered a concrete example: syrup producer Simply Organic Maple, using the assistant, saw a 57% increase in purchases and a 36% decrease in cost per purchase. She added that in the third quarter, almost 10 million advertisers used at least one of Meta's AI tools.

What is Google doing in response?

Google has a similar opportunity to deploy AI in ad products across its properties, including YouTube. Philipp Schindler, Google's chief business officer, said on the earnings call that the company is deploying its Gemini models "across our entire ads infrastructure," adding tools for advertisers and improving ad quality.

The harder problem sits inside search itself. Google's engine now competes directly with ChatGPT and Claude by surfacing more results through AI Overviews and AI Mode, where users primarily receive summaries rather than links to other sites. Search queries increased to a record in the quarter, Google said, but revenue growth is slowing — the core tension now driving investor anxiety.

How much are the two companies spending?

Both companies are betting so heavily on AI that they are pumping hundreds of billions of dollars into the infrastructure needed to build new models and services. Google projects up to $205 billion in capital expenditures this year. Meta expects to spend up to $145 billion.

Both are also aggressively trying to diversify revenue. Meta, which still counts on advertising for nearly all of its revenue, is pouring money into AI models and agents with the aim of building a subscription business. Google already has a large and rapidly expanding cloud computing division, which just reported over 100% growth to $31 billion in quarterly revenue, driven by demand for its infrastructure and its custom AI chips called tensor processing units, or TPUs.

The divergence in diversification is stark. Ads now account for less than two-thirds of Google's revenue. At Meta, they still account for 98% of sales.

What comes next?

Advertising remains the financial engine for both companies, but each is investing for a future that could look very different from the one that made them dominant. Google's path is further along by revenue mix; Meta's is concentrated in the one business where AI is currently working in its favor. The open question, pressed by UBS and Wedbush this week, is whether Google can prove it can monetize search in the AI era the way it did in the link-clicking one — and until it does, analysts say the stock is unlikely to recover its footing.