Noble Says AI Boom Combines Dot-Com Excess With Credit Risk

Former Fidelity portfolio manager George Noble warned that the AI boom combines the excesses of the dot-com era with risks resembling the subprime crisis. “Show me the ROI,” he told investor Steve Eisman in an episode released September 21.

Noble argued that a technology can transform the economy without rewarding every company that builds it. During the internet boom, traffic grew as expected, he noted, but infrastructure companies such as Global Crossing still went bankrupt.

Eisman’s episode notes point to another vulnerability: they estimate that OpenAI and Anthropic account for about 70% of hyperscalers’ AI revenue. Those cloud-computing giants are investing heavily in the infrastructure that supports AI services.

That spending increasingly involves borrowing. Goldman Sachs data cited by Reuters put hyperscaler debt issuance at a projected record $420 billion in 2027, up 60% from its 2026 estimate.

Bond investors are already asking for more compensation to hold AI-related debt. Reuters reported that spreads on AI-linked issuers stood around 115 basis points, compared with 78 basis points for the broader investment-grade market. The gap reflects heavy borrowing needs and uncertainty about returns, not a forecast of default.

Investor enthusiasm remains visible in chip stocks. Advanced Micro Devices crossed a $1 trillion market value for the first time on September 21, as shares rallied on expectations for growing AI-chip demand, Reuters reported.

For Noble, the key question is whether revenue and profits catch up with the capital flowing into data centers and chips. Investors will be watching AI customer demand, cloud-provider spending plans and whether the private labs at the center of the business can turn usage into durable income.