The U.S. economy has placed an unprecedented bet on the transformative power of artificial intelligence. According to Ming Lu, senior advisory partner at KKR, the current market concentration mirrors the Gilded Age of 1885, when railroad stocks accounted for 80% of trading on the New York Stock Exchange.
A Historic Concentration of Capital
Today, AI-related capital spending has surged to approximately 2% of U.S. GDP. This concentration is visible across all market segments:
- The “Magnificent Seven” boast a combined market capitalization of $25 trillion, representing 35% of the S&P 500—the highest concentration since 1929.
- In credit markets, AI-related companies' share of investment-grade bond issuance rose from 2% in 2023 to 10% in 2026.
- Venture capital saw AI capture 81% of a record $300 billion in global funding in Q1 2026, with just four firms (OpenAI, Anthropic, xAI, and Waymo) absorbing two-thirds of that total.
The Innovation Paradox and Productivity
Despite massive investment, Lu warns of the "Innovation Paradox": five decades of digital innovation have arrived alongside a decline in aggregate productivity growth. While consumers adopt new tech almost immediately, enterprises move at a glacial pace, particularly in service sectors that rely heavily on human judgment.
The Bank for International Settlements (BIS) has also flagged "circular financing" as a core vulnerability. In this model, AI firms invest in other AI firms, which then use those funds to purchase their backers' products. This suggests profits are being funded by investors rather than genuine end-customer demand.
“The U.S. growth engine now runs on a narrow set of mutually reinforcing drivers. If one stalls, the others lose power too,” Lu notes.
While the infrastructure currently being built—data centers and semiconductors—may eventually lay the foundation for prosperity, the full payoff will likely take decades, matching the historical timeline of canals, railroads, and the early internet.
