While equity markets remain bullish on mega-cap tech, the bond market is flashing a warning. The credit spreads for hyperscalers are widening as they take on massive debt for AI capex. This signals that debt investors, who are often more risk-aware, see growing financial strain that equity investors are ignoring.

Unlike equities, credit markets face a growing risk from the AI boom. As companies increasingly use debt instead of cash to finance AI and data center expansion, the rising supply of corporate bonds could pressure credit spreads to widen, even in a strong economy, echoing dynamics from the late 1990s tech bubble.

Widespread credit is the common accelerant in major financial crashes, from 1929's margin loans to 2008's subprime mortgages. This same leverage that fuels rapid growth is also the "match that lights the fire" for catastrophic downturns, with today's AI ecosystem showing similar signs.

A new risk is entering the AI capital stack: leverage. Entities are being created with high-debt financing (80% debt, 20% equity), creating 'leverage upon leverage.' This structure, combined with circular investments between major players, echoes the telecom bust of the late 90s and requires close monitoring.

The key signal for an AI bubble isn't just stock market commentary. It's the transition of data center buildouts from being funded by free cash flow to being funded by debt, particularly from private credit firms. This massive, less-visible market is the real stress test for AI's financial stability.

The AI infrastructure boom has moved beyond being funded by the free cash flow of tech giants. Now, cash-flow negative companies are taking on leverage to invest. This signals a more existential, high-stakes phase where perceived future returns justify massive upfront bets, increasing competitive intensity.

The AI arms race has pushed CapEx for top tech firms to nearly 90% of their operating cash flow. This unprecedented spending level is forcing a strategic shift from using internal cash to funding via debt issuance and reduced buybacks, introducing leverage risk to formerly fortress-like balance sheets.

Tech giants are no longer funding AI capital expenditures solely with their massive free cash flow. They are increasingly turning to debt issuance, which fundamentally alters their risk profile. This introduces default risk and requires a repricing of their credit spreads and equity valuations.

Unlike the dot-com bubble's weak issuers, the current AI debt boom is driven by investment-grade giants. However, the risk is that these stable companies are using debt to finance speculative, 'equity-like' technology ventures, a concerning trend for credit investors.