Tech giants' AI boom faces a rising cash-flow test

The latest results from Nvidia, Microsoft and Micron show that the AI boom is continuing to translate an increasingly capital-intensive business model into extraordinary financial growth. But which way will this proportionality swing going ahead?

Nvidia reported fiscal second-quarter revenue of $96.2 billion, up 106% year-on-year, with data center revenue reaching a record $89.0 billion, up 117%, according to the company.

Microsoft, meanwhile, reported $90.0 billion in revenue for its fiscal fourth quarter ended June 30, up 18% year-on-year. Azure and other cloud services revenue rose 43%, while Microsoft said its annual Azure revenue surpassed $100 billion for the first time.

Micron provided another striking example of the AI-driven surge. Its fiscal fourth-quarter revenue reached $54.23 billion, up from $11.32 billion a year earlier, while GAAP net income jumped to $37.70 billion from $3.20 billion. That translates into year-on-year increases of about 379% in revenue and 1,077% in net income.

The rally has also extended to the stock market. Nvidia shares were up more than 20% in 2026 through September 25, according to Reuters, while Micron's stock had more than tripled by September 30. Microsoft shares gained 36.4% in the third quarter, according to MarketWatch, their strongest quarterly performance in nearly three decades.

Yet the other side of the AI boom is also keeping pace: the amount of capital required to sustain it.

Microsoft spent $115.9 billion on additions to property and equipment in fiscal 2026, up from $64.6 billion a year earlier. Its operating cash flow rose to $182.9 billion from $136.2 billion. In other words, capital spending grew much faster than operating cash flow over the year.

Nvidia showed a similar pattern. Its fiscal 2026 purchases of property, equipment and intangible assets totaled $6.04 billion, up from $3.24 billion a year earlier, while operating cash flow rose to $102.7 billion from $64.1 billion.

Micron's numbers were different. Its net capital expenditures rose to $27.37 billion in fiscal 2026 from $13.80 billion, while operating cash flow surged to $89.68 billion from $17.53 billion. The company nevertheless signaled that spending will remain elevated as it expands manufacturing capacity to meet AI-related memory demand.

The distinction matters. The data does not show these companies are running out of cash — far from it. Rather, it shows that AI is changing the scale of investment required to support future growth.

Microsoft said its fiscal fourth-quarter capital expenditures reached $41 billion, while operating cash flow was $55.4 billion. About two-thirds of its quarterly capital spending went toward short-lived assets, primarily CPUs and GPUs, as customers expand AI and other computing infrastructure.

For investors, the question is therefore shifting from whether AI can generate revenue to whether that revenue can continue to justify the enormous infrastructure spending behind it.

That pressure is particularly visible in Microsoft's longer-term plans. The company said its calendar 2026 capital investment expectation is approximately $175 billion after accounting for changes in its data center leasing structure.

At the same time, demand remains strong. Microsoft reported $678 billion in commercial remaining performance obligations at the end of fiscal 2026, while Micron said customer commitments under long-term supply agreements had risen to $32 billion.

The AI boom is thus entering a new phase. Record sales and powerful cash generation are providing the financial fuel for another wave of investment, but the scale of that investment is also raising the bar for future returns.