Quote of the day by investor Warren Buffett on AI capex: "That's real money... That kind of money wasn't even put in the railroad business" — outlining his bullish long-term thesis on AI

AI demands a huge amount of energy, water, compute, and, of course, money. Big tech companies, including Google and Meta, have pledged huge sums of money toward the capital expenditure (capex) to continue the push to more powerful AI. But many inventors feel increasingly wary that this spending is simply swelling an already inflated bubble.

Laying the tracks

Speaking with CNBC in July 2026, the legendary investor Warren Buffett, who recently retired, weighed in on the capex debate.

Big tech companies are pledging a huge sum to the AI infrastructure buildout, which may reach up to $750 billion over 2026 and up to $4.5 trillion by 2030 among the four largest hyperscalers, including Meta, Microsoft, Amazon, and Alphabet. Many suggest this is further evidence of a bubble being fuelled aggressively by big tech companies doubling down on a technology that hasn't demonstrated meaningful returns.

But explaining his firm Berkshire Hathaway's 17.85 million-share purchase of Alphabet stock, disclosed in November 2025, Warren Buffett drew parallels between this level of spending and that during the 1800s to build the railroad system.

From digital to physical

As an investor, Buffett famously avoided software giants, suggesting they were asset-light businesses and didn't see the value in the investment propositions. This is a point he's since conceded he was wrong about. The firm he led made an additional $10 billion investment in Alphabet in June 2026.

The rationale is that there's currently a pivot underway in which these companies are shifting from the purveyors of digital products, namely applications and software, toward the physical infrastructure and compute to power AI.

Although the hyperscalers have been investing heavily in cloud infrastructure to power their software as a service (SaaS) propositions, the spending that AI commands is on a completely different level, as the figures show. That's why, in the end, Buffett believes that Alphabet proved a sound investment – given he believes that they have the cash flow to sustain the ongoing physical infrastructure buildout.