The news: Alphabet, Meta, Amazon, and Microsoft collectively represent roughly $15.5 trillion in market capitalization, per Business Insider, and this quarter they all pointed to the same catalyst—AI infrastructure demand is accelerating faster than anyone publicly projected. 

These four companies are now on track to spend a combined $725 billion in capex in 2026, a 77% increase YoY and a figure that would have seemed implausible two years ago. 

But that spending has financial backing. The quartet generated over $160 billion in advertising revenues in Q1, per Mumbrella, providing a cash engine that makes the capex wager look considerably less reckless. 

Meta’s ad revenues jumped 33% YoY, Alphabet's grew 15%, and Amazon’s went up 24%. Ad dominance helps bolster AI spending trends, but is it sustainable? It depends. 

• Projected capex is viable if ad revenues grow fast enough to fund AI build-out and buffer weak cloud/device demand—without eroding free cash flow.
• Each company is ostensibly making a multiyear infrastructure wager that the demand for AI compute, agents, and cloud services will justify spending at levels that would be questionable in any previous cycle. In some cases, these investments are already starting to pay off in higher AI and cloud revenue growth. 

Zooming out: Not to be left behind in Big Tech revenues and spending news, Apple is turning its attention to what it controls—hardware and software rather than joining the AI infrastructure arms race. 

AI, for Apple, arrives as a bonus: A reported multiyear deal with Google will bring Gemini Pro into a revamped Siri. That stands to unlock a new tier of AI-enhanced services and subscription revenues without requiring Apple to operate data centers at cloud hyperscaler levels.

While hyperscalers compete to control the backbone of the AI ecosystem, Apple controls the front end through its devices—which is how many consumers will access AI. 

Implications for marketers: The $725 billion capex surge and $160 billion-plus quarterly ad haul tell the same story—these platforms are simultaneously building the infrastructure layer and monetizing the attention layer, compounding their structural advantages with each cycle.

Brands should expect to pay more for ads on major platforms as AI-driven bidding pushes up their costs and less to build AI tools and experiences outside those platforms. The smartest play is investing in both.