The writer, head of macro credit and global investment strategist at Nuveen, notes that concentration risk in AI is not limited to equities. Over 35% of the S&P 500 is represented by large‑cap firms riding the AI cycle, crowding positions. The same thesis spills into credit, infrastructure, real estate and equities, giving a false sense of diversification. Financing has evolved from internal cash flow to a massive capital‑market push, with industry estimates of several trillion dollars in AI build‑out and unprecedented data‑centre investment.

An estimated $2tn of AI financing comes from the investment‑grade market, meaning hyperscalers could capture nearly 25% of the $7‑8tn US high‑grade market versus 5% now. High‑yield AI issuance has leapt to about $40bn, a 3% slice of the US high‑yield index. Hyperscalers have issued over $220bn in bonds this year, doubling their IG share. Demand remains strong, keeping spreads tight, but oversubscription has fallen from 5× to under 2×, and recent bonds underperform the broader IG market.

Investors are betting on AI longevity, covering six presidential terms and multiple rate cycles, yet the boom may end when expectations outrun reality. Mispriced AI bets reinforce each other, compressing spreads and pressuring balance sheets. The solution is greater selectivity, favoring cash‑generative infrastructure over incumbents priced for flawless AI execution.